FSI’s Latest Study Pinpoints Vehicle Stop Vulnerabilities

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Important officer safety findings from a groundbreaking study of vehicle stop performance have been reported by the Force Science Institute.

An analysis of various positions officers typically assume when talking to a driver of a stopped car and their immediate reaction to a sudden crisis reveals that:

  • No position proximate to the suspect’s vehicle can fully protect an officer from shots fired by a determined driver;
  • Positioning on the passenger side seems to offer the fastest access to a “mitigation zone” where the danger of incoming rounds is lessened;
  • In a surprise attack, officers trained to perform gun grabs or other disarming techniques tend to ignore that training in their desperation to escape the kill zone;
  • Trying to draw and return fire during a dash to safety slows down an officer’s flight;
  • Many officers, particularly those who back-pedal away from the threat, move at an angle that prevents them from ever reaching a zone of reduced danger.

“Some positions and movements are better than others,” says Dr. Bill Lewinski, FSI’s executive director who led the study team. “But you can’t depend solely on positioning to save your life on a traffic stop.

“If you decide to approach a vehicle you’ve pulled over, probably the most important elements for your safety will be your ability to control the suspect’s hands as soon as possible after beginning your approach and to verbally and psychologically dominate the interaction through effective communication and tactical maneuvers.”


Field work for the study, the first to systematically evaluate police officer responses to a sudden lethal threat during what appeared to be a “routine” traffic stop, was conducted last April in Hillsboro, OR, with the help of the training staff of Hillsboro PD. The goal, in part, was to determine if certain positioning during contact with a violator would work best to an officer’s advantage and to analyze officers’ immediate reactions to an unexpected, life-threatening crisis.

Details of what the testing involved were described in Force Science News Transmission #202. You can read it by clicking here or visiting www.forcescience.org/fsnews/202.html.

Ninety-three LEO volunteers of various ranks, ages, and years of service from police and sheriff’s agencies in the Pacific Northwest participated one at a time in the same scenario. Each was asked to exit a patrol car and approach the driver of a 2004 Ford Taurus that had been stopped for speeding 10 mph over the posted limit. The white male driver, alone in the vehicle, turned out to be an argumentative “sovereign citizen,” who barraged the officer with hostile disputes over his or her authority, lacked any legal license or registration, and presented confusing documents attesting to his “right” to travel without police interference.

Each officer, with sidearm holstered, approached the subject three times. The first two times, the driver was verbally abusive only for a period of 45 seconds. But during the third contact, he unexpectedly produced a pistol from a hidden location near his right leg and began firing blank rounds at the officer. The officers’ reactions were video-recorded by multiple time-coded cameras.

At the moment of attack, the tested officers were standing by the Ford’s center doorpost (the so-called B-pillar) at either the driver’s side or passenger’s side at different angles to the suspect’s vehicle, reflecting positions typically taken by officers in real-world situations that Lewinski has studied across more than 40 years.

On the driver’s side, officers stood: parallel to the car behind the doorpost, with left leg aligned with the post…parallel in front of the doorpost, with right leg near the post…perpendicular at a 90-degree angle to the post…or angled forward from the doorpost at a 45-degree angle. On the passenger side, they were angled forward from the post at a 45-degree angle. Roughly equal numbers of the test pool occupied each position.

For purposes of the study, the researchers calculated a “mitigation zone” encompassing the back half and rear of the vehicle. This is the area officers are often taught about in training where it’s harder for an offender to effectively target them from inside a vehicle and thus there’s less chance an officer will be hit. This zone of relative safety for the study fanned out at a 10-degree angle from just behind the B-pillar on the driver’s side and at a 45-degree angle on the passenger side.


“The first thing we confirmed from carefully studying the videos frame by frame was that no position an officer took relative to the suspect vehicle guaranteed his or her safety,” Lewinski told Force Science News. “Some positions were easier for the suspect to point at and shoot at–when an officer was parallel to the driver’s window, for instance–but he was able to comfortably and very quickly discharge rounds in officers’ direction however they were angled to the car.

“We also were able to confirm our findings from previous studies regarding how long it takes for a committed suspect inside a vehicle to present a weapon and fire the first round. That happened in this study in about one-quarter to one-third of a second, putting the officer far behind the reactionary curve. The attacks were so fast that no officer could have fired first, even if his gun was already on target, his finger was on the trigger, and he was primed to react.

“An officer who thinks that positioning alone will protect him can be tragically mistaken. There simply is no inherent safety in any position, and in this study there was no significant differences among positions as to how long it took the suspect to present his pistol and fire.”


Officers are commonly trained to “neutralize a suspect’s weapon” with disarming or deflecting techniques when sudden attacks occur at close quarters, Lewinski points out. “This is considered a faster response than trying to draw and shoot.”

However, in this study only 12 officers attempted neutralization–and only three succeeded. Two deflected the offender’s gun long enough to draw and fire their own; the third lunged into the car through the open window and choked the driver, keeping him from firing.

The other nine made a feeble attempt at neutralization–primarily trying to sweep the weapon aside with their off hand–but “didn’t follow through to finish the effort, resulting in the need to retreat and further expose themselves to the driver’s gunfire,” Lewinski says.

One of the most common gestures made in an immediate, startled response to the sudden threat was the officers “raising their hands or arms as if to shield themselves from the gun” before moving away from the vehicle. “This gesture, of course, has nothing to do with an effective reaction,” Lewinski notes.

From what the researchers observed in Hillsboro, it’s clear that if neutralization techniques are to be effective, “it is necessary to enforce more practice, training, and visualization strategies,” Lewinski says.


About 10% of the officers made no attempt either to neutralize the subject with a close-quarters response or to draw and shoot at him from some distance. “They simply retreated from the threat, disengaged without firing,” Lewinski says.

Of the vast majority who did shoot, when they did so proved significant. “The time-coding revealed that those who tried to draw and shoot while moving took an average of 0.39 of a second longer to reach the mitigation zone where their chances of being hit were reduced,” Lewinski explains.

“That amount of time translates into at least one extra shot by the assailant while the officer is still within an area of maximum vulnerability. It was faster to get to the safer zone first, then draw and fire rather than attempting the more complex motor action of drawing and shooting on the move. ”

(Because blanks were used in the guns of officers and the offender alike, accuracy could not be confirmed for any shots.)


Officers predominately side-stepped in some fashion or back-pedaled in distancing themselves from the threat. About 17% of those who back-pedaled and 11% of those who side-stepped never made it to the mitigation zone. Overall, nearly one in five officers in the study failed to reach the zone.

“They moved back at angles that actually carried them away from the safer area, remaining in the offender’s easier line of fire and, on the driver’s side at least, exposing themselves to potential dangers from traffic,” Lewinski observes.

For those who did make it to the zone, the time required for back-pedaling and for side-stepping to get there were “very similar.” But Lewinski points out that “a considerably higher percentage of those who back-pedaled were unsuccessful in reaching the mitigation zone. Also, those who back-pedaled exposed their center mass and head to the suspect for a greater amount of time.”


Officers standing at a 45-degree angle to the doorpost on the passenger side were able to reach the mitigation zone in the least amount of time on average–about 1.5 seconds from the start of the assault.

On the driver’s side, officers standing parallel to the vehicle behind the doorpost were able to move fastest–but took 2.04 seconds to reach the mitigation zone on average. That may not seem statistically significant, but “that difference in time could mean the difference between life and death for some officers,” Lewinski says. “A rapid-firing suspect could get off two to three more shots before an officer could reach a safer position on the driver’s side. The other driver-side positions were significantly slower.

“Positioning yourself on the passenger side appears to offer a significant advantage,” Lewinski says. “A potential assailant tends to be hindered not only by not expecting you to approach there but also by obstructions inside the vehicle, such as headrests which interfere with their ability to target and track you. And if there is trouble, you will likely be able to retreat more quickly to a less vulnerable position, according to our findings.”

Officers committed to making driver-side approaches, despite the disadvantages, “should have adequate training in close-contact weapon neutralization and train to disengage before drawing,” Lewinski advises.


A fuller report on these initial discoveries, including statistical specifics, has been accepted for publication by the peer-reviewed journal Law Enforcement Executive Forum. That report is authored by Lewinski and his research colleagues, Jennifer Dysterheft, Dawn Seefeldt, and Dr. Robert Pettitt. Publication date has not yet been announced.

Currently underway is additional analysis of the data gathered in Hillsboro to explore elements such as officer-subject communication, alternative physical reactions, psychological and memory considerations, and other critical control and response factors. Results from these aspects of the study will be released in Force Science News as soon as they are available.

Specific recommendations for training modifications will not be made until all data is thoroughly analyzed, Lewinski says. “These findings seem to offer some suggestions about directions we should go, but there is still a lot we don’t know about precisely what to do in training.”

Meanwhile, the Patrol and Tactical Operations Committee of the International Assn. of Chiefs of Police, of which Lewinski is a member, has asked for a report on the findings of the study. Officer safety during vehicle stops is a concern that the IACP is currently studying in an effort to devise new training and performance guidelines.

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