“Perhaps the most compelling, ongoing, and logical reason for law enforcement’s continued interest in high-speed vehicle pursuits has been its concern in balancing the values of crime control and offender apprehension with ensuring the safety of all parties who potentially might be involved—police officers, suspects, victims, bystanders, and the community.”¹ This balancing test has formed the cornerstone of pursuit policies, training, and practice for the past several decades.

Police pursuit records provide some frightening statistics. First, the majority of police pursuits involve a stop for a traffic violation. Second, one person dies every day as a result of a police pursuit. On average, from 1994 through 1998, one law enforcement officer was killed every 11 weeks in a pursuit, and 1 percent of all U.S. law enforcement officers who died in the line of duty lost their lives in vehicle pursuits. Innocent third parties who just happened to be in the way constitute 42 percent of persons killed or injured in police pursuits. Further, 1 out of every 100 high-speed pursuits results in a fatality.²

Within the context of these horrific statistics, officers are charged with protecting public safety, which often requires serious personal and social risks. Although empirical evidence is scant, each study conducted on police pursuits enhances the available knowledge. That is the main purpose of the authors’ research, along with providing policy makers and trainers another tool to assist them in formulating evidence-based decisions.³

Dynamics of Pursuits

Obviously, the goal of the officer is to apprehend and arrest the suspect. While the officer originates an enforcement stop, the suspect, if he flees, initiates a pursuit.⁴ When this occurs, the officer must respond to the suspect—who has no rules—with a balanced and reasonable approach to apprehend him. Accordingly, the officer must become aware of personal capabilities and take into account environmental conditions that may affect his ability to accomplish the overall mission of the police, to protect lives. The officer must factor into the decision-making process the risk created by the suspect’s driving, the potential actions of innocent bystanders and others who may become involved, and the influence of his actions on the suspect’s driving. In addition, the officer must consider the likelihood of apprehension in the decision to continue a chase. In other words, the officer must balance the goals of law enforcement with the public’s safety.

The officer must understand that when a suspect refuses to stop for the emergency lights and siren, a common encounter turns quickly into a high-risk and dangerous event where the “show of authority” may negatively affect the suspect’s driving. If the suspect continues or increases his reckless operation of the vehicle, the officer, basing his reaction on policy and training, must respond to the potential benefit and risk of the pursuit and also understand the influence of the chase on the participants. The need to “win” and make that arrest can be influenced by the adrenaline rush felt by the officer who also must recognize that the fleeing suspect will have the same experience. Because research has demonstrated the impact of this on an officer’s vision, hearing, motor skills, and decision making, it would appear necessary to prepare for the same adverse affect it could have on fleeing suspects.⁵ Clearly, a pursuit is an exciting event and involves one person running to escape and another chasing to catch. One important challenge for the officer is that there are only limited ways to get the suspect to stop, including a tire deflation devise, a precision immobilization technique (PIT) maneuver at proper speeds and locations, or an application of deadly force.⁶

The dynamics of most pursuits include the fleeing suspect raising risks to the welfare of the officer, the public, and himself by not stopping and then driving recklessly. The fleeing suspect is attempting to escape the consequences of his actions and avoid being taken into custody. Most pursuits are for minor offenses, and whether those fleeing suspects have committed a serious crime is pure speculation.⁷ In addition, research has shown that if the police refrain from chasing all offenders or terminate their pursuits, no significant increase in the number of suspects who flee would occur.⁸

One of the dilemmas faced by law enforcement is whether or not to continue a chase. Stated differently, the question is, What are the consequences of continuing or terminating a dangerous pursuit? Most policies include the balanced and reasonable approach and require officers to terminate when the risks created by the chase outweigh the need to immediately apprehend. It is understood that when an officer terminates his active involvement in a pursuit, the suspect likely will escape apprehension at that time. Many progressive policies instruct officers who terminate a chase to stop, pull over, radio their position, and drive away from the suspect to signal that the officer has given up and the suspect has “won.” The point of this tactic is to notify dispatch of the termination and to inform the suspect that he can slow down and drive safely without constantly looking in his mirrors. The question is, When will the suspect slow and his driving become safe? Without a doubt, the reckless actions of the fleeing suspect can create a dangerous situation for all concerned. The question of when the suspect will slow down and return to reasonable and safe driving, however, remains.

Insight from Suspects

Because knowledge of suspects’ behavior is limited to anecdotal information from officers and empirical data from the suspects themselves, four researchers conducted a study as part of a grant from the National Institute of Justice wherein they interviewed suspects who had fled from the police.⁹ Their effort, the first systematic study to quantify the perceptions of suspects involved in pursuits, provided information on a variety of topics, including the demographics of those who fled from the police (their average age was 26, and 94 percent were male), as well as what happened (30 percent of the suspects crashed, 30 percent stopped, and 25 percent outran the police) and why they fled (32 percent were driving a stolen car, 27 percent had a suspended driver’s license, 27 percent wanted to avoid arrest, and 21 percent were driving under the influence).¹⁰ One of the more interesting findings from the suspects concerned their willingness to slow down when the police stopped chasing them. Approximately 75 percent reported that they would slow down when they felt safe. They explained that on average, they would have “to be free from the police show of authority by emergency lights or siren for approximately two blocks in town...and 2.5 miles on a freeway.”¹¹ In other words, suspects who have fled from the police report that once the officer terminates the pursuit, they will slow down within a reasonable period.

In addition to the suspects’ data on pursuit termination, a researcher surveyed members of the Airborne Law Enforcement Association to determine their experiences with pursuits. The data revealed that after ground units terminated their pursuit, “on average, suspects continued driving dangerously for 90 seconds before slowing.”¹² The researcher concluded that “results from this pilot study, other prior research, and anecdotal evidence suggest most fleeing suspects will return to safe driving behavior within a relatively short period of time after ground pursuits are terminated. However, there will be those cases where despite law enforcement efforts to pursue less frequently and to terminate more pursuits as quickly as possible, fleeing suspects will create tragedies.”¹³

During years of training officers in decision making, instructors have heard a wide array of responses concerning the behavior of fleeing suspects during pursuits. The anecdotal information has indicated that officers realize suspects will not continue their recklessness forever and at some point will slow down. Conventional wisdom has suspects reducing speed quickly in town and after a longer period on a highway or freeway. Discussions of officers’ beliefs about the behavior of fleeing suspects have been neither extensive nor systematic; they have occurred during training, debriefings, and in other informal situations.

While the research has been scant, the opinions about suspect behavior have been widespread. Discussions held in training sessions point to a wide variety of opinions concerning pursuits, the proper police response, and suspect behavior. What is known is that pursuits are dangerous and place officers, citizens, and suspects at risk. What is not known is how to make them safer for all concerned. Some policies mandate the termination of a pursuit when the risks outweigh the benefits. The thinking behind this approach is to have the police not be part of the problem but part of the solution. If possible, a safe and proper PIT maneuver can bring an end to some chases. In many other cases, it is more appropriate for the officer in a pursuit to turn off his lights and siren and stop or turn around. This behavior is designed to signal to the suspect that he is safe and can slow down and remove the risk to the public. Once the suspect receives this signal, it is anticipated that he will slow down. As in any aspect of law enforcement, defensible decisions should be based on empirical evidence. In pursuit matters, however, suspects have claimed that they will slow down and become safer relatively quickly after a pursuit is terminated. But, what do officers have to say about these issues?

No attempt has occurred to quantify officers’ experiences or perceptions about the behavior of fleeing suspects. The authors’ study, therefore, complements the research conducted with suspects by asking police officers many of the same questions.

Perceptions of Officers

Starting in July 2007 and ending in June 2008, the lead author surveyed participants in the Law Enforcement In-Service Training in Emergency Vehicle Operations and Police Pursuits course at the Minnesota Highway Safety and Research Center in St. Cloud. He collected data from 1,015 officers, representing 10,968 years of experience. Agency size ranged from two to 1,624 sworn officers, with the average being 40. Data also were collected from 362 preservice recruits who attended training during the same period. Obviously, this method of data collection relies on memory and perception. It is important to recognize that any self-reported data may have errors of memory and maturation. However, when requesting information that is neither sensitive nor consequential, it is likely that respondents will provide honest answers. The researchers gave the officers and recruits sufficient time and instructed them to report their information as accurately as possible. A few officers and recruits did not answer some questions, but the missing answers were minimal.

The officers reported being involved in a total of 10,384 pursuits of which 959 (9 percent) resulted in a collision involving a police vehicle and 3,571 (34 percent) ended with the suspect crashing. While some involved multiple objects, the authors estimated that 35 to 40 percent of all of the pursuits resulted in a crash. These officers terminated 1,133 (11 percent) of their pursuits with 447 of those involving motorcycles. The officers advised that they believed 227 (20 percent) of the pursuits they terminated resulted in a crash. In addition to halting pursuits by turning off the emergency lights and siren, they used the PIT maneuver 1,018 times that resulted in 35 (.03 percent) injuries and no deaths, demonstrating that the PIT can be effective and efficient when used properly.

The preservice recruits reported that they believed that 61 percent of the pursuits would end in a crash and that if they terminated a pursuit, 39 percent of those would crash anyway. In other words, these young recruits believed that by terminating the pursuit, 22 percent fewer crashes would occur.

Table 1. Officers’ Perceptions of Fleeing Suspects’ Behavior

Perhaps the most important aspect of this research involved the officers’ and recruits’ opinions concerning when a fleeing suspect would slow down after a chase had been terminated. The authors asked the officers and recruits, “If a pursuit was terminated, how far do you believe the suspect would run if in town and if out of town?” Table 1 shows the answers for in-town pursuits in blocks and for those conducted out of town in miles and tenths of a mile.

On average, the officers reported that suspects would quit running after 1.7 blocks in town. Overall, 98 percent advised that suspects would stop within five or fewer blocks. The other two percent believed that the suspects would continue fleeing for a greater distance.

In out-of-town pursuits, the officers thought that on average, suspects would quit running after seven miles. Seventy percent believed that suspects would stop within 10 miles, whereas 30 percent felt that the suspects would continue beyond that distance. The officers who believed that suspects would quit running before 10 miles reported an average response of slightly less than four miles. That is, those officers who believed that suspects would be impacted by their lights and sirens being turned off felt that suspects would quit running after 3.9 miles. Similarly, 62 percent of the officers indicated that suspects would quit running within five or fewer miles with an average response of 3.5 miles. Interestingly, the recruits—who had no real experience with policing or pursuits—advised that fleeing suspects would quit running after 2.9 blocks in town and 4.2 miles out of town. Overall, the authors interpreted these findings to indicate that most officers generally believe suspects will quit running after about two blocks in town and approximately four miles out of town.

Implications of Research

Balancing the need to immediately apprehend a fleeing suspect with the risk created by the chase forms the foundation of police pursuit policies. The operational meaning of this test is that once an officer terminates his pursuit, the suspect will slow down and blend into traffic, go home, or exit the vehicle and try to escape on foot. In other words, pursuit policies are based on the notion that once an officer or supervisor terminates a pursuit because the risks are too great, the public will be safer than if the pursuit is continued. Unfortunately, empirical research on the actions of fleeing suspects is scarce, but the data in this study expressed officers’ opinions on what suspects will do after they terminate their active attempt to apprehend such individuals.

Evidence-based decision making in law enforcement has been an important improvement in policy development and training.¹⁴ As researchers and police agencies form partnerships and conduct collaborative studies, the results can be used to design best practices and evaluate practitioners. As a result, both the law enforcement community and the public will benefit from decisions based on systematic research findings. Additionally, policies and training can be explained to officers using quantitative and qualitative research findings as opposed to anecdotes.

Conclusion

While more research needs to be conducted on the actions of fleeing suspects after a pursuit has been terminated, it is noteworthy that fleeing suspects and officers have provided similar answers to the questions of suspect behavior. Specifically, the majority of suspects reported that they would slow after two blocks in an urban area, while the officers thought the suspects would do so in just under two blocks. On freeways, the majority of the suspects reported that they would slow after 2.5 miles, whereas most of the officers felt they would after just under four miles. Because the reality may be somewhere in between these estimates, more research is needed to test these findings. While the research reported here or anywhere else cannot predict the actions of a specific suspect, it does suggest that in the aggregate, fleeing suspects will behave within specified parameters.¹⁵

It is important to consider that pursuit policies are based on the belief that fleeing suspects will slow down at some point after a pursuit is terminated. Research findings support that principle and provide empirical data that can guide policies and training. Of course, whether or not police officers should terminate an active attempt to apprehend a suspect is a different question that depends on what they know or have reasonable suspicion to believe that the suspect has done.