A Publication of the Memphis Shelby Crime Commission
Volume 4, Number 1, April 2001

This study, The Role of Technology in Supporting Police Pursuits, is the fifth in a series of White Papers on issues related to public safety. While the primary method of research for the Memphis Shelby Crime Commission (hereafter, the Crime Commission) is best practice investigations, not all topics lend themselves to this format. The purpose of the White Paper is to cover special issues, policies and concerns not specifically addressed by the Crime Commission's Best Practice Studies.

A White Paper is usually defined as a statement of proposed government policy on a particular subject. In government departments, White Papers are drafted by civil servants, but the final decision concerning their content is at the discretion of the agency head in line with stated administration policies. A common procedure after the publication of a White Paper is for the governmental organization to initiate legislation or policy construction embodying the position proposed. As an aid to this task, a White Paper serves as a form of public scrutiny of the proposed policy. It is often the case that governmental agencies accept comments from interested bodies, as well as the general public, on the content of White Papers. Such comments have varying degrees of influence upon the legislation that follows.

While the Crime Commission is an independent, non-governmental, nonprofit organization, the purpose of its White Papers closely mirrors that of governmental agencies. In some instances, the content of these White Papers may serve as statements of position by the Board of Directors or staff of the Crime Commission. However, the primary goal is to formulate an assessment of an issue for public comment and review. Upon publication, an outcome of the Crime Commission's White Paper may be the ratification of the stated position as the accepted standard of practice, but the success of the White Paper will not be measured by whether or not the stated position becomes standardized.

In articulating the positions of this White Paper, the Crime Commission is not rendering legal advice as to the legal ramifications of adopting the recommended positions. The recipient of this paper is therefore advised to seek legal opinion and the recipient should not rely on the positions contained within this document as legal opinion.

Other than physical arrest, vehicle pursuit is the most common high-liability area of law enforcement. In the past, the dominant question for law enforcement has been whether to pursue or not to pursue, and until recently, few viable options have existed for law enforcement to stop fleeing vehicles safely. To improve the ability of local law enforcement officers to halt fleeing vehicles and to enhance the safety of both officers and the public in Memphis and Shelby County, the Crime Commission examined a number of alternative approaches that use technological devices to mitigate the negative outcomes of police pursuits.

For analytical purposes, scholars have defined police pursuit as "an active attempt by a law enforcement (police) officer on duty in a patrol car to apprehend one or more occupants of a moving vehicle, providing the driver of such vehicle is aware of the attempt and is resisting apprehension by maintaining or increasing his/her speed or by ignoring the law enforcement officer's attempt to stop him/her."

The study makes several recommendations, including the need to create and maintain a model data collection system for pursuit driving and the need to review and update pursuit policies so that they include the specific manner, circumstances, and authorization required for the deployment of technology, as well the need for pursuit-specific training and supervision. The Crime Commission cautions against a quixotic search for a single, ideal technology, and suggests concentrating on a number of potentially effective technological options from which to choose. Of the technology currently available, the Crime Commission recommends that mechanical devices, such as tire deflation devices, be strongly considered for immediate local use. In the category of emerging technologies, the investigation indicates that electrical systems, cooperative systems with law enforcement activation, and sensory enhancements (improved warning devices) all appear to be high priority devices.

Technological developments in the next decade may help to facilitate major changes in law enforcement responses to police pursuits. Joint ventures now occurring between law enforcement and industry are indicative of future markets for advanced technology. Continued improvements in technology to slow or stop a vehicle may reduce risks in pursuits.

One hundred fifty years ago, when Memphis was the burgeoning capital of the of the Old Southwest, filled with freshly minted cotton fortunes and mischief of one kind or another, lawbreakers would flee from justice by mounting a horse or a mule and galloping out of town.

At the dawn of a new millennium, times have changed in what is now called the capital of the Mid-South, but the criminal propensity to avoid detection and, when discovered, to occasionally avoid apprehension by fleeing pursuing officers, certainly has not.

At the request of Memphis City Council Member Brent Taylor and the urging of several local municipalities, the Memphis Shelby Crime Commission agreed to review the ways in which technology can be used to reduce the frequency and severity of police vehicle pursuits. Specifically, the Crime Commission was asked to investigate how technology can mitigate dangers to law enforcement officers and the public in the instances where a police pursuit is warranted. The discussion that follows will analyze police pursuits from a rational perspective that only well-regulated pursuits should be allowed when the danger to the public of the violator remaining at large outweighs the danger to the public created by the pursuit.

For analytical purposes, scholars have defined police pursuit as "an active attempt by a law enforcement (police) officer on duty in a patrol car to apprehend one or more occupants of a moving vehicle, providing the driver of such vehicle is aware of the attempt and is resisting apprehension by maintaining or increasing his/her speed or by ignoring the law enforcement officer's attempt to stop him/her".¹

The U.S. Supreme Court has determined police vehicular pursuits that result in a collision not intended by the pursuing police officer do not violate an injured party's fourth amendment rights. In the absence of an argument on fourth amendment grounds, victims of high-speed police chases must argue that their substantive due process rights have been violated in order to assert a constitutional claim.²   Recent court decisions have also indicated the need for explicit formal policies to regulate pursuit behaviors and tactics, a topic to be discussed shortly.

It cannot be emphasized enough, however, that arguably the most important legal issue for public officials is that pursuits are a discretionary activity that involves substantial risks to police officers, bystanders, and communities, as well as substantial liabilities for police agencies.³ To counter these liabilities, a number of state legislatures have gone so far as to enact laws granting immunity to officers when pursuing a fleeing suspect in vehicles when that suspect represents a threat to public safety. An alternative to this approach, one recommended by the National Institute of Justice’s Pursuit Management Task Force, is legislation that ensures that fleeing from a lawful attempt at detention/arrest in a motor vehicle is a serious crime.

Police pursuits are receiving increasing public attention and critical media coverage. The basic dilemma associated with police pursuit of fleeing suspects is deciding whether the benefits of potential apprehension outweigh the risks of endangering police officers, the public, and suspects in the chase. The issues addressed in the study and research of police pursuit echo those discussed in research on police use of deadly force, and the general trend in dealing with high-speed police pursuits is to subject them to the same scrutiny applied to the use of deadly force.⁴ On the one hand, too many restrictions placed on police use of pursuit could place the public at risk from dangerous individuals escaping apprehension. On the other hand, insufficient controls on police pursuit could result in needless accidents and injuries.

In the ethical framework known as utilitarianism, the utility of an action can be determined based on the actual or potential outcome for maximizing the greatest good for the greatest number of people. This paper proposes three basic principles for evaluating from a utilitarian perspective the value of police pursuit technology: the value of all human life; the avoidance of physical injury, and the use of police force only to prevent physical harm to others. Any cost-benefit analysis for police pursuits can be reached by viewing pursuits through these principles and by answering three questions that should guide every pursuit: when to pursue, what to do during a pursuit, and when to abandon a pursuit.⁵ Following from these questions, further criteria with which to calculate the hazards versus benefits of continuing the pursuit include the time of day, weather conditions, traffic congestion, and presence of pedestrians. Police must consider a number of factors, including: the suspect’s violence or threatened violence, the nature of the crime involved, the immediate threat posed by the suspect should apprehension be delayed, severity of the suspect’s active resistance and attempts to evade, whether citizens are involved in the pursuit, and the supervision and management of the pursuit as it unfolds. These criteria must also be weighed when determining the appropriateness and effectiveness of pursuit technology.

More than a decade of research findings confirms that collisions are a predictable outcome of police pursuits. As an example, Auten (1994) studied seven hundred police pursuits in 129 Illinois police agencies to determine the risks of accidents, property damage, personal injuries, and fatalities. Results revealed that 271 pursuits (38.7 percent) resulted in an accident, for a rate of 1 accident for every 2.6 pursuits. Among the 700 pursuits, 26.1 percent resulted in property damage, 10.9 percent resulted in a personal injury, and 1.7 percent (12 pursuits) resulted in a fatality. The property damage averaged $1,425 per accident. Using estimates from the National Safety Council for injury and fatality accidents, Auten estimated the economic loss from Illinois pursuits he studied to be $8,563 per pursuit initiated and $22,118 per pursuit-related accident. It is important to note that no estimates for legal costs or costs of agency time spent investigating the accident or possible policy violations were included in this figure.

Further analysis revealed that 45.8 percent of the accidents involved only the fleeing suspect's vehicle, while 24.4 percent involved the suspect's vehicle and a citizen.⁶  Such research underscores the importance of law enforcement objectively assessing the risks of a collision before initiating a pursuit, as well as pointing to the potential of technology to mitigate some these risks.

While the Crime Commission was asked to inform a dialogue on pursuits by investigating the application of technology to mitigate pursuit risks, it merits discussing police pursuits and pursuit driving in a fuller context, lest we repeat the mistake of so many other communities by deliberating on important law enforcement issues in an information vacuum. So before fully exploring the deployment of pursuit technology, let us briefly discuss four subjects that should undergird any pursuit technological initiative. These subjects are policy, training, public opinion and research.

Departmental policies regarding high-speed pursuit are important for several reasons:

• to reduce the number of injuries and deaths;

• to guide officers in knowing when and how to pursue;

• to maintain the basic law enforcement mission to enforce the laws and to protect life and property; and

• to minimize agency liability.

While this study is not ultimately concerned with pursuit policies, nor have local policies been comparatively analyzed, the relevance of such policies to the issue of pursuit technology does merit discussion. Given the dangers of police pursuits to the general public, police officers and suspects, police agencies across the United States have adopted a variety of approaches to vehicular pursuits, ranging from banning them altogether to allowing wide officer discretion. In the policy pronouncements made by the International Association of Chiefs of Police (IACP) in the 1990s, officer discretion is dependent on local laws, geographic and traffic conditions, availability of backup, field supervision, pursuit termination devices, and departmental philosophies. While the IACP concluded that it would be impractical to impose a single, standardized policy on law enforcement agencies worldwide, they determined that policy agencies should develop, adopt and enforce formal written directives tailored to the needs of the jurisdiction, with an emphasis on public safety concerns. Such directives should specify the procedures and tactics to be used for initiating, continuing and ending vehicular pursuits. These directives should also address the training of the agency’s officers, supervisors, and communications personnel on pursuit-related issues.⁷

A number of studies have explored the relationship between the restrictiveness of police policies and police pursuit outcomes. Using data from the Aurora, Colorado, Police Department Crew et al. found that policy changes such as those recommended by IACP had no significant effect on the proportion of accidents to the number of pursuits. Crew’s study suggested that police officers generally complied with policies and were not evading policies through nonreporting, and that more restrictive policies do not increase noncompliance with pursuit reporting requirements.⁸ The study also concludes that police vehicle pursuit policies that are the most comprehensive are generally not the most restrictive, since they do not simply prohibit or permit vehicle pursuits, but comprehensively specify those circumstances under which pursuits should be undertaken and the parameters under which they should be conducted, continued, and terminated.

More recently, a nationwide survey of 436 police agencies conducted by the Police Executive Research Forum (PERF) showed that, as the level of policy restrictiveness increased, pursuits did decrease, albeit slightly.⁹ Policy restrictions were usually accompanied by other changes that mitigated negative outcomes to pursuits. When policies became more restrictive, more thorough training was provided to police recruits and in-service police officers. Similarly, when more systematic evaluations of all pursuits were conducted, pursuits typically decreased. As policies and overall pursuit restrictiveness became clearer and there was tighter control over police officers, police officers were less likely to use excessive force in the apprehension of fleeing suspects. Other studies, such as the comprehensive police pursuit study by the National Institute of Justice, have shown an even stronger relationship between policy changes and the number of pursuits conducted by an agency. When one of the case study sites, Metro-Dade, adopted a "violent felony only" pursuit policy in 1992, the number of pursuits decreased 82 percent the following year. In 1993 Omaha, another case study site, changed to a more permissive policy, permitting pursuits for offenses that had previously been prohibited; the following year, the number of pursuits increased more than 600 percent.

Implementation of restrictive pursuit policies may or may not affect accident rates in proportion to the number of pursuits- the research to date is not conclusive in this regard. Nonetheless, pursuit technology deployment does presuppose a pursuit policy that both allows for and prescribes the circumstances in which such technology can be appropriately deployed as a forcible stop technique. According to the 1995 survey by McGue and Barker of pursuit policies in 188 Alabama law enforcement agencies, fewer than half had policies allowing the use of forcible stop techniques in pursuit situations.¹⁰ The authors also found that the amount of training in forcible stops was not related to agency size. A preliminary examination of the Memphis Police Department pursuit policy suggests that the policy may need to be revised to include the appropriate deployment of technology, if the use of technology in pursuits were to become a standardized departmental practice.¹¹

In its guidelines for operational policies, the Commission on Law Enforcement Accreditation (CALEA) recommends that written directives governing pursuit of motor vehicles include the following:

1. evaluating the circumstances;
2. initiating officer’s responsibilities;
3. designating secondary unit’s responsibilities;
4. specifying roles and restrictions pertinent to marked, unmarked, or other types of police vehicle involvement in the pursuit;
5. assigning dispatcher’s responsibilities;
6. describing supervisor’s responsibilities;
7. using forcible stopping/roadblocks;
8. specifying when to terminate pursuit;
9. engaging in inter and intra-jurisdictional pursuits; and
10. detailing a procedure for reporting and an administrative review of the pursuit.¹²

The CALEA guidelines governing pursuit emphasizes two key points. First, a pursuit policy should be cross-referenced with an agency’s deadly force policy. The equation of pursuits with deadly force is justified by the data, which will be presented shortly. Pursuits can also serve as a prelude to the use of physical force; sometimes the use of force is justified, as with the apprehension of a serious felon, and sometimes it is excessive, as in the videotaped and much-publicized beating of motorist Rodney King. Second, the approach to pursuits should be holistic in scope, taking into consideration the responsibility of all personnel involved, as well as all contingencies, including the use of forcible stop techniques.¹³

Training is another important non-technological solution that can mitigate, or in its absence, exacerbate, the risks inherent in police pursuits. In its national study of police pursuits, NIJ found that many departments acknowledged taking only limited steps to train their officers on skills and procedures regarding pursuits. For example, although 60 percent of the agencies reported providing entry-level driving training at their academies, the average time devoted to these skills was estimated at less than 14 hours. Once in service, the amount of additional training offered averaged only slightly more than 3 hours per year and focused on the mechanics of defensive and/or pursuit driving rather than on issues that should be considered when deciding to continue or terminate pursuits. Respondent agencies may have spent at least some time teaching officers how to pursue, but training devoted to when--or why-- to pursue appears to have been minimal or nonexistent.¹⁴

While common sense dictates that public streets are inappropriate areas for pursuit driver training, on the job and in the field are the places where most pursuit training takes place. Clearly, many police officers and supervisors recognize the inherent dangers of pursuits and are making efforts to control them. However, the NIJ pursuit study did reveal a lack of initial and continuing training on the issues involved. According to the study’s authors, a critical component of police training should be an analysis of the specific risk factors as well as the benefits of pursuit driving. This education requires careful training in departmental policies and the reasoning that underlies the more recent, restrained philosophies and policies. Echoing this sentiment, CALEA suggests that in-service training should include not only the review of pursuit policies/procedures, but also training in forcible-stop techniques, particularly roadblocks.¹⁵

There are a number of training opportunities that can help officers to learn from their mistakes in a more controlled environment than the field. One obvious need, often cited in earlier literature on pursuits is for training in high-speed driving and cornering during police pursuits, because driving fast is dangerous and is a skill that needs to be learned and is perishable.¹⁶ The application of basic defensive driving tenets to emergency response situations is a similar need.¹⁷ Some municipalities have a strong emphasis on defensive driving training. For example, Nassau County (New York) trains recruits in maneuvering for three days at a former airfield set up with cones and tires, including a lane change, stop sign, and emergency stop. The 25- to 30-person class is divided into half so the instructors can work with a small number at a time. Recruits are lectured in the morning before going to the course for hands-on training, including an aided case with an ambulance, in which the officer drives the ambulance while the ambulance driver is in the back with the patient. Nassau County’s pursuit policy is restrictive about who can chase— roadblocks and chases with unmarked cars are prohibited, and the number of cars that can chase is limited. Similarly, Suffolk County’s (New York) training course is a former missile base with streets laid out with stop signs, traffic lights, and a sprinkler system that can make curves slippery. The recruits have classroom training first, which deals with the county policies, pursuit policy, civil liability and the physical principles of driving the car. Civil liability has been the motivation behind the standardization of training in both of these communities.¹⁸

Although this report does not specifically address training technologies, a number are designed to enhance pursuit driving capabilities. Two examples are driving simulators and the Skid Car. A simulator uses sights and sounds to provide the feeling of an actual situation – a capability that can be used to train people from many different disciplines, including law enforcement. Law enforcement agencies are using simulation technology to train personnel in the use of firearms and in emergency vehicle operations -- training that allows officers to hone skills while reducing risk. The Skid Car, which was designed in Sweden, provides actual skid control experience in real-time situations. The Skid Car is a frame and hydraulic dolly that attaches to the test vehicle. Instructors then have the ability to lift the car off the ground, thus inducing controlled skid conditions. These maneuvers are performed at speeds of less than 25 mph, thereby reducing the dangers of high-speed skids.

C. Public Opinion

Police vehicular pursuits are attracting increased interest by police scholars, government officials, the public and the media. Because of the intense scrutiny, it is important to frame a discussion of pursuit technology within the context of the attitudes held by key stakeholders.

The recent comprehensive NIJ study of pursuits conducted by Alpert includes extensive research on both police attitudes toward pursuits as well as public perceptions of police pursuit driving. Results of the study indicate that law enforcement personnel and members of the public focused on the severity of the offense committed by the suspect when supporting a pursuit. The second most important factor was the risk to the public (as defined by traffic, road conditions, and the weather). A concise review of this work will help to provide some perspective on the recommendations that will follow.¹⁹

• Police Officer and Supervisor Opinions

In surveys of 779 police officers and 175 supervisors in four police departments (Metro-Dade; Omaha; Aiken County, South Carolina; and Mesa, Arizona), respondents were asked whether they would engage in or approve a pursuit under low- and high-risk conditions. The major finding is that the percentage of all officers willing to engage in a pursuit, and of all supervisors willing to approve a pursuit, increases as the severity of the crime increases. In other words, the need to immediately apprehend a dangerous suspect is the most important concern for law enforcement personnel. Police said that the most important risk factors to consider during a pursuit were traffic conditions and weather. This emphasis on risk factors is important for the Crime Commission’s pursuit technology inquiry, in that advances in technology could lead to changes in risk factors. While the data indicated widespread agreement about officers' willingness to pursue when a fellow officer has been shot or when violent felons have committed murder, there was wide variation within and among agencies regarding other situations. For example, the more experienced officers in Omaha and Aiken County were more likely to engage in pursuit of misdemeanor property crime suspects under high-risk conditions than their less experienced counterparts. Officers in Mesa, Arizona, with more than 5 years of experience were nearly twice as likely to pursue suspects of traffic violations under low-risk conditions than the less experienced officers. These somewhat counter-intuitive findings suggest that some officers, especially veterans, may need retraining on the dangers of pursuit.

• Recruit’s Opinions

The NIJ study also surveys of police recruits in South Carolina and Miami, Florida before training and after training. Similar to the results obtained from the officers and the supervisors, the percentage of recruits who were willing to engage in a pursuit increased as the severity of the crime increased. The importance of the risk factors also decreased as the seriousness of the offense increased. Data collected from recruit classes both before and after training at four locations show that the training had an effect on altering some opinions reported by the recruits. For example, prior to the training course, 77, 79, and 86 percent of recruits at each of three locations (St. Petersburg, South Carolina Highway Patrol, and Metro-Dade) were willing to engage in pursuit for a stolen vehicle under low-risk conditions. After the training, the percentage decreased to 59, 70, and 73 percent respectively. At Metro-Dade, before training, 100 percent said they would pursue a DUI suspect under low-risk conditions; after training, 73 percent said they would. These results indicate that training programs can be designed to support policy objectives and that jurisdictions could assess whether or not training programs are meeting stated goals.

• Public opinion

Interviews with 555 residents of Aiken County and Omaha indicate support for police in apprehending individuals suspected of violating the law. The public agreed with law enforcement personnel that the seriousness of the offense increases the need to pursue suspects, but the level of risk to the public decreases that need. Although some differences in opinion were found between races and socioeconomic levels for some law violations, no differences were found for serious felony offenses. While the study does indicate that citizens support the police in their attempt to apprehend suspects for serious crimes, this support diminished, however, when the nature of the offense was not as serious. In addition, findings suggested that public support decreased when information about the dangers of pursuit was presented. Support for pursuit was strong and criticism was minimal when a police officer was shot or a felony was committed. Support for pursuit was minimal, especially under high-risk conditions, when a traffic violator was pursued. Media coverage of pursuit-related issues may also have an effect on public perceptions. In Omaha, the print and electronic media covered pursuit driving regularly, with stories that included changes in policy, accidents, injuries, and proposed legislation. In Aiken, only minimal coverage was reported on a few tragedies.

• Suspects' opinions

D. Research on Police Pursuits

While collecting valid and reliable data on policing activities is a perennial problem for police research, this problem is particularly relevant when studying activities such as police vehicle pursuits, an activity that is both organizationally sensitive and controversial. In his national survey on pursuit and use of force from police agencies throughout the United States, Alpert found that only 31 percent of the 737 responding police agencies systematically maintained pursuit statistics, 71 percent. According to Wells and Falcone (1996), the absence of a systematic database of all police pursuits is a fundamental problem common to most municipal police departments. On the other hand, officer surveys from the Michigan State Police indicated that slightly more than half of 1,180 respondents opposed police agency collection of monthly data on pursuit activities.²⁰ The lack of officer support for the collection of data is a significant impediment to the implementation of technology, because, as we will see shortly, a cookie cutter approach to pursuit technology is ill-advised for a variety of reasons, and one cannot implement technology in a community without collecting data on the precise circumstances in which police pursuits are occurring.

Because of the lack of available data, and the limited resources available to independently collect and evaluate such data, the Crime Commission will assume that a hypothetical data set of local pursuits would conform to the general characteristics of previously published data on pursuits. That is, this paper will consider Memphis as a fairly typical large municipality in terms of incidents that precipitate pursuits, length of time of pursuits, and outcomes. Fortunately, the high degree of convergence among the various studies and data sources makes such an assumption at least somewhat reasonable.

If a more comprehensive approach to the analysis and reduction of police pursuits is desired, local law enforcement agencies should consider requiring the production, maintenance and evaluation of police pursuit data as a routine outcome of the day-to-day activities of those police agencies.²¹ The collection of pursuit data can be done in several ways. A number of prominent police departments place the collection of pursuit data within the context of a departmental pursuit review board. For pursuit data collection strategies, separate police pursuit recording forms are clearly preferable to reliance on official police records, since they tend to yield more systematic and detailed data. An intriguing alternative to both official reports and separate pursuit forms involves the police recordings of radio transmissions. Police radio transmissions are appealing as an alternative or supplemental data source for police vehicle pursuit forms for three reasons: 1) they avoid conventional biases, 2) they are immune to problems of retrospective editing since data are reported and recorded in process, and 3) they avoid the problem of recall because data are recorded as they occur.²² They can also be extremely useful learning devices for law enforcement departments interested in continuously improving the pursuit responses of officers, supervisors and dispatchers.

There has been a substantial increase in research on the risks and benefits of high-speed pursuit since the 1983 California Highway Patrol study, one of the early research studies of pursuits. Two important findings of that study were that 77 percent of the suspects were apprehended, and 70 percent of the pursuits ended without an accident. A number of comprehensive studies applying scientific controls have been conducted since 1983, addressing causation factors and outcomes of police pursuits. Notwithstanding dissimilar data collection procedures and levels of data, the data are presented as representative of the current knowledge base of pursuit driving. When the data are combined and the results analyzed, the studies, most of which are presented in Tables I and II (located in the appendix) show striking similarities.

The general data on police pursuits germane to this investigation can be divided into five categories: length of pursuit, light conditions of pursuit, percentage initiated for felonies, outcomes of pursuits, and geography. Each category is briefly discussed below, with quick facts on police pursuits concluding this section.

1. Length of Pursuit

The relatively short length of pursuits suggests that most police pursuits develop randomly and extemporaneously. The length of police pursuits has very important consequences when considering technological applications. This issue will be discussed further in the technology section of this report.

Payne and Fenske (1997) analyzed the rates of police pursuit accidents, injuries and fatalities of the Michigan State Police personnel between 1988 and 1990. Comparative data revealed pursuit accidents were significantly more likely to occur during darkness and less likely to occur during daylight hours. Injuries, however, were more likely to occur in daylight and darkness than during dawn or dusk light conditions, while fatalities were found to occur more during darkness than during daylight, or dawn and dusk.²³ Light conditions are also an important factor in determining the effectiveness of pursuit technology.

3. Factors of Engagement

Interestingly, Table I suggests that most pursuits are not in response to serious and violent felonies, but rather to other types of incidents, usually traffic violations and misdemeanor offenses. The felony pursuit estimates from the data sources presented in Table I indicate a range from a low of 11 percent to a high of 30 percent. In the Illinois police radio transmission dataset, 27 percent of the pursuits were initiated in response to suspected felonies or to apprehend persons wanted on felony warrants.

One must be cautious, however, when looking exclusively at the initial violation. It would appear that a more valid approach is to examine the relationship between the initial violation with which a police pursuit began and the final charge. In California, data were collected from a statewide pursuit information database and through a police agency survey. Survey responses were received from 94 California Highway Patrol offices, 113 police departments, and 12 county sheriff offices. In 1994, 5,339 police pursuits were initiated in California— 52 percent began when a police officer attempted to make an enforcement stop for a minor violation and the violator fled. Of these pursuits, 73 percent of those apprehended in police pursuits were charged with felony violations and about two-thirds of felony arrests were for charges other than evading a police officer.²⁵ These data suggest a number of explanations, including an undisclosed felony had already been perpetrated or was in progress; a felony act was committed in the course of pursuit, such as a hit and run with injuries or the discharge of a weapon at officers; a felony warrant for the suspect driver was outstanding; or felony contraband was secreted in the vehicle.

4. Outcomes of Pursuits

The National Institute for Justice study included case studies of three departments that include an in-depth analysis of pursuit outcomes Researchers reviewed case records of more than 1,000 pursuits conducted by Metro-Dade (Miami), Florida, officers between 1990 and 1994; 229 pursuits conducted by officers in Omaha, Nebraska, between 1992 and 1994; and 17 pursuits conducted in Aiken, South Carolina, between 1993 and 1994. Researchers found that pursuit-related accidents occurred more frequently when pursuits were conducted for felonies than for non-felonies, when they occurred on surface streets rather than on highways or freeways, and when they happened in urban and suburban areas rather than in rural areas. Also, increasing the number of vehicles involved in police pursuits not only increased the likelihood of apprehension, but the chance of accidents, injuries, and property damage increased as well.

The prediction of personal injury resulting from a police pursuit depended primarily on four variables in Metro-Dade: the greater the number of police cars the greater the likelihood of injury. Involvement of other police agencies also increased the likelihood of injury. High-speed chases resulted in more injuries than low-speed pursuits, and chases in residential areas resulted in more injuries than those conducted in nonresidential areas.

In Omaha, pursuit-related property damage occurred in 40 percent of pursuits. In Omaha also, the pursuits most likely to end in an accident were those initiated because of traffic violations or felonies. The pursuits least likely to end in an accident were those initiated because of vehicles being identified as "suspicious."

In Metro-Dade, the likelihood of the suspect's escape was found to depend on the number of police vehicles and police departments involved in pursuit (increasing the number of vehicles decreased the likelihood of escape), the location of the pursuit (fewer suspects escaped in business districts than in residential or rural areas), and the time of day (fewer suspects escaped during daytime hours than at night). In Omaha, the likelihood of escape was related to supervisory assistance (the lack of supervisory assistance increased the likelihood of escape), the number of police cars involved in the chase (pursuits with one police car resulted in more escapes than chases with more than one police car), the speed of the chase (chases conducted at higher speeds resulted in more escapes than those at lower speeds), the location of the pursuit (chases in residential areas resulted in more escapes than those in rural areas), and the level of traffic congestion (chases in light traffic resulted in more escapes than those in heavy traffic).

In Omaha, pursuits initiated for reckless driving or driving under the influence (DUI) were the most likely to end in an arrest (75 percent), while pursuits initiated because a vehicle was "suspect" resulted in the smallest proportion of arrests (43 percent). Officers were most likely to terminate the pursuit voluntarily when it was initiated for suspect vehicles (29 percent), and least likely in chases initiated for felonies (16 percent).

The data from the national survey revealed that the more police cars involved in a pursuit, the more likely a collision will result. However, data also showed that the more police cars involved in a pursuit, the more likely an apprehension will be made. One implication could be that in violent felony situations, it may be reasonable to take the risk of causing traffic accidents by increasing the number of police vehicles in the chase in order to improve the likelihood of apprehension. On the other hand, one of the more important statements that can be made of pursuit outcomes can be found below:

Data from the studies reviewed show that a suspect who does not know he or she is being pursued will drive in a reasonably safe manner, and suspects who know they are being pursued and drive dangerously will slow down after the police terminate their ground pursuit. The above finding has key policy implications when the discussion turns to two pursuit technology strategies— the employment of sensory systems and the use of helicopters.

5. Geographical Distribution of Pursuits

The National Survey of Police Pursuits, conducted between October 1994 and May 1995, reported that municipal police agencies were significantly more likely than county police agencies to restrict pursuits to felony incident. Municipal agencies also tend to restrict pursuits to marked vehicles and impose supervisory responsibility more often than county police agencies.²⁷ However, Table II suggests that rate of pursuits ending in collisions appears higher for municipal than for county law enforcement agencies. Higher population density as other variables such as terrain and traffic congestion could explain the higher rate found in municipal areas.

II. Technology

The Crime Commission derived most of the information on technological applications to police contained in this report from the National Law Enforcement and Corrections Technology Center (NLECTC). The Western Center of NLECTC, located in El Segundo California, authored in 1998 what is arguably the most comprehensive published study of pursuit technology to date. The Vehicle Stopping Technologies Committee for the pursuit study report included members of municipal law enforcement, federal law enforcement, the Army Research Laboratory, and NLECTC staff. The Crime Commission is greatly indebted to the authors of the report for making members of the technology research team available for perspective and guidance, and for permission to liberally reference the perspectives on technology contained in the final document.²⁸

In the statewide survey research conducted for its report, The Pursuit Management Task Force (PTMF) found that more than 50 percent of all pursuit collisions occurred during the first 2 minutes of a pursuit, and more than 70 percent of all collisions occurred before the 6th minute of a pursuit. This information is consistent with the research presented earlier in this paper and significant in that it illustrates that a pursuit technology must be able to be very rapidly deployed and used in order to have a significant impact in preventing pursuit-related collisions. Large, complex, or stationary devices, unless used in preemptive mode, appear then to have little potential effect on pursuit collisions because of the delay required to set them up.

The PTMF grouped technologies into five categories— mechanical, electrical, chemical, cooperative, and sensory. The Crime Commission maintained this grouping strategy and updated some of the material where technological advances had occurred after the publication of the PTMF final report. Vehicle-stopping technologies in each category are reviewed for their usefulness in law enforcement pursuit applications, and include technologies either currently available, under development, or potentially available.

The PTMF report finds that no single technology offers a universal solution to pursuits.

While many different technological applications were reviewed, it is important to note that no single device is currently available or even on the horizon that would provide a "silver bullet" that eliminates pursuit risks and ensures that fleeing suspects will be apprehended. The PMTF study finds that there is currently no single technology on the horizon that affords a "universal" solution to pursuits.

Of the various technologies reviewed, spiked strips were found to be the most frequently used, and currently, the most effective technology readily available. Most of the other reviewed technologies were in the conceptual or pre-commercial phases and require substantial testing and development. In light of the need for additional research, the task force recommended the continued allocation of resources for pursuit technology research, development, and commercialization as well as resource assistance in the transfer of defense-related technologies to civilian law enforcement for their use. The PMTF also noted the importance of cooperation among law enforcement officials, technologists, and administrators in the testing and development of these technologies.

Each category, beginning with mechanical systems, will be presented separately and discussed briefly. While the list of pursuit technologies presented in this report is not necessarily exhaustive, the most important concepts and devices that appear to have merit for use in present and near-future vehicles-stopping applications have been included. This discussion on the five classification systems for pursuit technology will be followed by a brief overview of technology deployment platforms. A series of recommendations and summary observations will follow.

1. Mechanical Systems

In current use, the most common types of vehicle stopping technologies are mechanical in nature. While there are a plethora of mechanical systems, the most important of which are presented in Table III, many consist of pre-emplaced tire deflation or barrier systems. However, mechanical system also includes nets/entanglers as well as tagging systems (signaling devices or other identifiers placed on a fleeing vehicle to allow it to be tracked by law enforcement without having to engage in pursuit). Helicopters, both a deployment platform and a pursuit termination technology, will be discussed at the end of this section.²⁹

Many progressive police agencies have chosen to stick with time-proven methods, such as tire-deflation devices, until alternative technologies become more affordable and reliable. The most successful tire deflation systems in current use appear to be "spiked strips" that consist of sharpened, hollow steel spikes that are press-fitted into expandable plastic strips of various lengths. When a pursued vehicle runs over a strip, the spikes are embedded in the tires and pull loose from the strip, remaining in the tires and allowing air to escape at a controlled rate for a safe deflation. This prevents blowouts and allows safe steering to continue until the tires are flat and the vehicle slows to a manageable speed. Two products in particular, the Stinger Spike Strip and Stop Stick, are known to be widely available for police agency purchase.³⁰ A vehicle passing over this common tire-deflation device has its tires punctured so that it is safely disabled within 20 to 30 seconds. This device ensures officer safety and can be easily and quickly deployed and removed from the road after the targeted vehicle has passed over it.³¹ According to the PMTF, spiked-strip technology appears to be the most widely used pursuit termination technology available today.

Unlike commercially available barrier strips, the prototype technology of retractable spiked barrier strips can be deployed on a roadway with the spikes retracted. Then, from a safe and strategic location, the spikes can be activated to extend and retract to target specific fleeing vehicles. Also, this unobtrusive strip can be placed across the road far in advance of the fleeing vehicle, with passing vehicles incurring no damage. Once the fleeing vehicle approaches and the hollow spikes are extended, puncturing and becoming embedded in the tires, the escape of air is rapid but uniform, so that the vehicle can come to a controlled stop. The barrier strip, which is designed to be comparably priced with current non-retractable spiked barrier strips, could perhaps be routinely installed along favored pursuit routes.³²

Similarly, the checkpoint barrier strip is a lightweight tire deflator that, when deployed and activated remotely at a checkpoint prior to being driven over, will rapidly deflate a vehicle's tires, rendering an offender's vehicle incapable of high speed as the offender begins to accelerate away from the checkpoint. This technology would be particularly useful in rendering large trucks incapable of attaining high speed in order to evade border patrol checkpoints. The deflator consists of an array of 1/2-inch hardened, hollow steel spikes and support blocks magnetically retained in a 6-foot deflator bar. When run over, the spikes separate from the bar and are retained in the tire, providing an unobstructed air passage for deflation. The deflators are lightweight, quickly deployable, reusable, and leave no roadway debris after use.³³

One of the oldest tire deflation devices still in use is the caltrop, which usually takes the form of a four-pointed metal star that is arranged in such a manner that when it is thrown on the ground, three points form a base on the ground and the fourth points up for puncturing. Caltrops can be dispersed easily from any ground or air platform. Exceptionally strong caltrops with spike lengths of 4 inches or more are required for large trucks or heavy-duty tires on off-road vehicles to avoid simply crushing them. As a tool for civilian law enforcement, caltrops generally are not recommended.

Mechanical barriers of various types have also been used in some form or another for a long time to stop moving vehicles, as well as for their most common use as fixed or moveable roadblocks. Although some inflatable or quick reaction barriers exist, newer varieties include large-area "arrestor" types that operate like the cable arresting systems designed to stop high-speed aircraft, such as those used on aircraft carriers, at civilian airports to keep aircraft from overrunning the runway in emergency landings, or to reduce the peril of aborted takeoffs. In the PTMF surveys of line officers and citizens, both groups ranked barriers as the most risky and least effective of the technologies listed. Their limitations include pre-emplacement, the injury and liability potential of vehicle crashing through an immovable barrier, and the possible that barrier systems may fail to cause a vehicle to come to a stop.

Yet another type of mechanical vehicle stopper concept that may come into widespread use in the future is the net or entangler system. Nets/entanglers use high strength mesh materials, such as Kevlar, coupled with a launching system to ensnare the drive wheels and axles of the vehicle or to encapsulate the entire vehicle. Such a system is being developed and tested under U.S. Armament Research, Development and Engineering Center (ARDEC) Nonlethal Technology (NLT) program sponsorship by Primex Aerospace Company. The technology, known as the Speed Bump system, consists of a pop-up net placed inside a "speed bump" that crosses the roadway. The target vehicle drives into the net and is brought to a stop by a braking system attached to the net. Claims of stopping capability up to 60 mph have been cited, even for large trucks. Net or entanglers appear to be simple to set up and operate, and are designed to stop more common types of vehicles without leaving debris on the road surface. Deceleration, though swift, appears to be less forceful than slamming on one’s brakes for a panic stop. While the systems have strong potential at fixed points, such as border crossings or checkpoints, their lack of portability, bulk, requirements of two persons for setup as well the time required for setup³⁴ all diminish the potential of entanglers for typical police pursuits. However, as a site security system, they may be less lethal then fixed barricades.

Rather than trying to bring a vehicle to a stop, vehicle taggers are a mechanical technology that is designed to track vehicle movement without having to actually engage in a pursuit. Once a vehicle is tagged, pursuing officers may disengage and track the vehicle’s movements until it comes to a stop. The fleeing vehicle tagging system concept can consist of a launcher; a projectile that is less than lethal to bystanders if it should miss its intended target; a radio frequency transmitter tag embedded in the projectile; a polymer adhesive within the projectile to secure the tag to the fleeing vehicle; and a receiver-tracker.³⁵ Alternative means by which a vehicle could be tagged include placing it by hand on a vehicle that may be used to flee, and firing or otherwise placing it on a pursued vehicle from the primary pursuit vehicle. Other potential technologies under consideration by the National Institute for Justice for tagging and/or tracking vehicles are sensors installed along the highway for identifying stolen cars as they drive by, paint darts for marking vehicles for later interception, or radio transmitters attached to cars that would allow for pre-deploying of cruisers.

Tagging systems have limited potential for significantly impacting typical police pursuits, according to the PTMF. On the one hand, the impact of tagging systems is optimized if aided by air support, so that suspects cannot elude capture. On the other hand, the need for tagging or tracking technology is significantly mitigated if air support is readily available. The deployment of tagging systems would in all likelihood require a high degree of accuracy, and the launching of a projectile at a moving object involves some degree of hazard. Finally, these systems by design do not cause a fleeing vehicle to stop, so that the dangerous acts of a driver can continue unabated until the driver decides to stop or the vehicle

In summary, many of the mechanical stopping technologies have inherent weaknesses in their application, the most significant of which is that they must be pre-emplaced. Another drawback to most pre-emplaced mechanical devices is the possibility of their acting upon chase vehicles as well as civilian vehicles that are either following too closely for the device’s operator to disengage the device or that just happen to be in adjacent traffic. While these drawbacks are indeed formidable, they should not detract a department from purchasing such devices. With increased training and continuing product improvements, mechanical devices such as spiked strips are one of the few current technologies capable of bringing a pursuit to a safe conclusion.

Advancements in helicopters and onboard auxiliary equipment have improved the ability of police departments to conduct pursuits more successfully. According to available data, helicopters can decrease the use of high-speed pursuits and increase apprehension rates.³⁶ Alpert (1998) collected data from Baltimore from July 1995 through June 1996 and from Miami-Dade for the calendar year 1996 to determine the effectiveness of helicopters in pursuit activities. Both Baltimore's and Miami-Dade's helicopters are equipped with a combination of crime-fighting tools— the radio, searchlight, infrared heat sensing system, and camera--that together are effective tactical resources available to police during patrol and response activity.

Miami-Dade helicopters were involved in 43 pursuits during this period, with 39 suspects arrested, while Baltimore helicopters were involved in 89 pursuits, with 74 suspects arrested. These arrests rates, 91 and 83 percent respectively, compare very favorably the 72 percent apprehension rate for ground pursuits cited in previous research.

The data presented above suggest that helicopters can provide a valuable service to law enforcement during a pursuit. In pursuits, helicopters can provide important assistance without being noticed, especially by tracking pursued vehicles and alerting ground units to the direction, location, and any activities that are going on in their view. This critical function allows the ground units to turn off emergency equipment and slow down to protect public safety while maintaining visual contact with the fleeing vehicle. This tactical advantage has proven to be very successful in the apprehension of fleeing suspects and the reduction of risk to the public, especially when one recognizes, as well pointed out previously, that the most frequent reason for the conclusion of a pursuit is the suspect driver voluntarily stopping.

There are two obvious disadvantages to the use of helicopters. Their cost can be prohibitive, particularly for small to mid-sized departments. Also, given that the average length of pursuit is under five minutes, opportunities to play a major role in assisting ground units are dependent on the air unit’s ability to become quickly involved in the pursuit prior to its termination. The easiest way to reduce the second concern is to maintain frequent air patrol during times of day when pursuit activity is heaviest; in Baltimore and Miami-Dade the heaviest period for pursuits was at night. On the other hand, the more amount of time is spent in air, the higher the operational costs for the unit will be.

Helicopters can be a credible component of mitigating the inherent risks to police pursuits. However, if the role of helicopters were to increase, it becomes important to develop policies guiding their activities, including specific circumstances when a ground unit supervisor authorizes his or her officers to continue ground pursuit. As part of these policy determinations, use of the spotlight during pursuits will require structured guidelines to maintain it as an important crime-fighting tool. Guidelines need to be based on the spotlight's effect on the fleeing suspect and environment, to ensure that it is used effectively, for its intended and appropriate goal, in a manner that does not encourage a suspect to take more risks or continue dangerous actions.

Table III. Analysis of Mechanical Systems.

Electrical systems are technologies that use either direct injection or radiative energy to upset or destroy a fleeing vehicle’s electrical components, resulting in loss of power.³⁷  Since the direct injection and radiative systems are quite different in terms of their deployment, each will be discussed separately. Table IV presents a quick summary of the strengths and limitations of electrical systems.

1. Direct Injection

According to experts at the National Law Enforcement and Corrections Technology Center, direct injection requires direct electrical contact with the targeted vehicle. Electrical contact can come either from an electrical storage source³⁸ or an explosively driven power source.³⁹ Electrical energy from a stored source can then be automatically or command discharged through connecting wires by a set of two wire contacts protruding from a strip on the ground or a single wire-to-ground connection, causing current to pass through the frame and engine ground paths. The current that is passed from the stored source through the wires would burn out or otherwise disrupt the engine (if the engine controls were electronic), ignition, or other critical electronic modules of the fleeing vehicle without disrupting the occupants. While a pre-emplaced contact set for the discharged energy is the more obvious deployment strategy, an alternative is to launch a set of wire contacts from a chase platform to the pursued vehicle, with the voltage or current source either on the chase platform or contained in the package launched at the pursued vehicle.

The general consensus on direct injection systems from the PTMF is that they show greater promise for fixed positions, such as site security or checkpoints than they do for typical police pursuits. They may also have greater utility in rural areas where potential escape routes are rather limited. Below is a description of a direct injection product that is currently being marketed to law enforcement agencies.

 

2. Radiative Systems

Radiative electrical vehicle stoppers differ from direct injection in that there is no actual contact required between the vehicle and the energy source. Theoretically, this eliminates the need to place objects on the roadway in the path of the fleeing vehicle or to launch a projectile at it. Thus, radiative systems would have the same impact as their direct injection counterparts, but with a significantly different delivery system.

Chemical systems describe those technologies that interfere with a fleeing vehicle’s internal combustion by inserting one or more nonhazardous chemicals into the combustion equation, upsetting the balance among fuel, heat, and oxygen. Chemicals are introduced into a vehicle’s engine through its air intake system in either gaseous, liquid, or powder forms. The chemical(s) introduced can stop the engine in one of two ways— either by negatively altering the fuel-to-air ratio necessary to continue internal combustion, or by enhancing the combustion process to the extent that it causes a "knocking" process that can cause the engine to seize or be destroyed.

Chemical systems pose four significant problems as a forcible stop method. First, from technical standpoint, finding a suitable deployment platform is a major obstacle, especially when considering the high-speed nature of most police pursuits. Secondly, also from a technical standpoint, one must ensure that the engine of the pursued vehicle cannot be started after clearing itself of the injected chemicals. Third, the anticipated public concern raised by the notion of shooting chemicals at occupied vehicles makes the prospects for chemical stoppers highly unlikely for civilian law enforcement purposes. Finally, the potential loss of driver control must also be considered.

Most pursuit technology experts have concluded that the current presentations of chemical systems do not appear to have significant potential for widespread law enforcement use.

4. Cooperative Systems

Cooperative systems are sometimes considered a subset of the electrical technologies, and describe systems that are pre-emplaced by a vehicle’s owner or manufacturer as a theft-deterrent or vehicle recovery system and which may or may not be activated by law enforcement to cause a fleeing vehicle to come to a stop.⁴²

At least in theory, cooperative systems hold tremendous promise as a pursuit termination technology, provided that they were universally installed and law enforcement could activate them. Cooperative systems can, through the tracking of vehicles, provide one of the safest and most cost effective ways to terminate pursuits. There are several options for activating such a system, including owner activation, telephone or pager activation, and laser activation. However, the options that provide law enforcement with the discretion to activate such systems create several concerns about privacy as well as requisite enabling legislation. One solution to these concerns would be incorporate authorization for law enforcement to activate cooperative systems into the annual registration renewal process. This could be accomplished by permitting and facilitating voluntary input on state motor vehicle registration that a car is equipped with such a system, and that the owner has approved law enforcement activating the system in prescribed situations.

The continued examination of cooperative systems is worthy of ongoing research, and recommendations for legislation to enhance the utility of these systems seem reasonable and timely.

Sensory technologies are those devices that impair or irritate a driver’s optical, auditory, or other senses non-chemically, as well as those that enhance the public’s visibility or recognition of an approaching emergency vehicle. Of the five pursuit technology classification systems, sensory devices are unique, in that no sensory systems are a forcible stop technique in the true sense of the term. However, recalling that research indicates that the most frequent reason for the conclusion of a pursuit is the suspect driver voluntarily stopping, one can immediately recognize that the psychological aspects of suspects choosing to stop and the devices that could induce such behavior are worthy of exploration.

For example, enhancements to emergency vehicle warning devices could influence pursued vehicles to voluntarily stop. The typical combination of overhead lights and electronic sirens have several shortcomings. They were designed for emergency response situations, generally at lower speeds than most pursuits. They were also designed to bring attention to the approaching emergency vehicle and not a vehicle being pursued, as they do not provide much advance notice of an oncoming vehicle during high-speed pursuit situations. The effectiveness of audio devices in particular is diminished when the source vehicle is approaching at high speeds.

Several of the sensory technologies that are currently being researched include bright lights, sonic or shock waves and similar methods to create sufficient discomfort for the driver to cause him or her to choose to stop. The technology must be able to be focused on the suspect vehicle, with measures to ensure that the discomfort of the driver does not compromise his or her ability to properly control the moving vehicle.

Each technology used to terminate or prevent a pursuit requires a platform for its deployment. Without belaboring this topic, a platform is defined by the Pursuit Management Task Force as "the means by which the technology is taken to the location of a pursuit, or the location at which or device to which the technology’s hardware is secured during its deployment."⁴³ Sometimes, as in a device deployment directly from a pursuit vehicle, these components would be the same. Other times, such as with spiked strips, the transporting vehicle would not be the same as the deployment device (i.e., the pursuit car does not "launch" spiked strips).

Technology experts employed by the PMTF reviewed various technology deployment platforms such as helicopters, ground chase vehicles, other police units, fixed placements, and specialized vehicles. In view of the high percentage of ground collisions that occur during the first few minutes of a pursuit, standard police vehicles were strongly preferred as deployment platforms for general law enforcement operations. Obviously, any technology that would not be suitable for use in congested environments would be probably not benefit deployment from a helicopter platform. Other deployment platforms were also found to be feasible for applications involving fixed-point security or checkpoint operations such as border and toll crossings, immigration checkpoints, and site operations.

This investigation by the Memphis Shelby Crime Commision points to several issues for consideration by those local and state leaders that assist in the development and implementation of public policy for law enforcement. First, the need to create and maintain a model data collection system for pursuit driving cannot be overemphasized. Without this information, the impact of local policies on police pursuit cannot be determined, and the specific technological devices that would mitigate safety concerns for police pursuits cannot be identified.

Flowing naturally from the need for data collection and analysis is the need to review and update pursuit policies so that they include the specific manner, circumstances, and authorization required for the deployment of technology. Third, assuming changes in policy are made, local law enforcement leaders should evaluate the need for pursuit-specific training and supervision, recognizing that officers cannot make proper and appropriate decisions with minimal or no training. Changes in written policy may require careful training to implement the changes and to be held accountable for abiding by any new provisions. If technology changes are embraced and policy and training modifications made, law enforcement executives should consider reviewing all pursuits through the production and evaluation of after-action reports. Departments should also consider developing an internal pursuit review board to review all police vehicle pursuits engaged in by their officers.

Of the technology currently available, the Crime Commission recommends that mechanical devices, such as tire deflation devices, be strongly considered for immediate local use. The Crime Commission also recommends that the expanded use of helicopters be considered, and that cost-sharing of helicopter services among metropolitan law enforcement agencies be explored. In the category of emerging technologies, the Crime Commission recommends that local and regional law enforcement leaders continue their advocacy of adequate resources being allocated to continue, expand, and accelerate research, development, testing, and commercialization of viable pursuit technologies, and to support continued technology transfers from defense to civilian law enforcement. In particular, electrical systems (both retractable direct injection electrical systems and radiative electrical systems, including high-power microwave), cooperative systems with law enforcement activation, and sensory enhancements (improved warning devices) all appear to be high priority devices. Local governments alone will not be able to finance the research and development necessary to bring some of these exciting technological possibilities online.

While the list of action items for local and state officials is significant, the Pursuit Management Task Force draws a parallel between the development of pursuit-related technologies and lunar exploration. Local and state government never put a man on the moon- it took a concentrated and costly effort by the federal government for Neil Armstrong to take his "giant leap for mankind." Similarly, it will require a continued investment by the Federal government to actuate the potential of some the most promising pursuit technologies.

The Crime Commission also cautions readers to avoid the quixotic search for a single, ideal technology. Instead, interested parties should consider a variety of technologies that can be used as circumstances dictate. Since our research indicates that there is no silver bullet, it seems prudent to concentrate on a number of potentially effective technological options from which to choose.

Local leaders may also wish to consider legislation that ensures that fleeing from a lawful attempt at detention/arrest in a motor vehicle is a serious crime with significant penalties. In addition, the advance of cooperative technology makes the opportunity for law enforcement activation a legitimate possibility; therefore, it seems reasonable to conclude that such activation would require enabling legislation, and this probability strongly merits further investigation. Finally, concerned leaders should also think about creating opportunities to further public education about pursuits, both their inherent danger and the greater public good served by pursuing violent offenders.

Police vehicle pursuits are fraught with peril for police, suspects and innocent bystanders. Other than physical arrest, vehicle pursuit is the most common high-liability area of law enforcement. In the past, the dominant question for law enforcement has been whether to pursue or not to pursue, and until recently, few viable options have existed for law enforcement to stop fleeing vehicles safely. To improve the ability of local law enforcement officers to halt fleeing vehicles and to enhance the safety of both officers and the public in Memphis and Shelby County, the Crime Commission has examined a number of alternative approaches that use technological devices to mitigate the negative outcomes of police pursuits.

Technological developments in the next decade may help to facilitate major changes in law enforcement responses to police pursuits. Joint ventures now occurring between law enforcement and industry are indicative of future markets for advanced technology. Continued improvements in technology to slow or stop a vehicle may reduce risks in pursuits. The use of helicopters, while expensive, already can allow law enforcement to monitor a fleeing suspect unobtrusively and alert ground units when he or she stops. Spike strips, devices that slowly deflate a vehicle's tires when run over, have been available for several years, and enhancements suggest that the utility of these devices are likely to increase. Nets and high-tech barricades are being developed to bring vehicles to a stop. Emerging technology promises remote-control devices that can allow police to shut down a car's electrical system.

While no simple solution exists for the complex problem of police pursuits, technological advances this decade promise efficient, non-lethal methods for law enforcement to stop fleeing vehicles that will minimize risk of death, injury, property damage, and liability to the agency, yet at the same time will provide a high probability of making an arrest and recovering the vehicle.