Decreasing Crash Rates through Increased Perception of Officer Presence

By Ken Clary

In the summer of 2017, while attending the Center for Evidence-Based Crime Policy Symposium at George Mason University, [as a National Institute of Justice – Law Enforcement Advancing Data and Science (LEADS) Scholar], I was fortunate to be able to attend an evidence-based policing lecture hosted by Dr. Chris Koper and Dr. Cynthia Lum. During that instruction, the group of police practitioners was called-to-action to infuse evidence-based research and practices into law enforcement within our purview whenever possible. As a commander with the Iowa State Patrol – with a primary mission of roadway safety – a frequent measure of our success involves measuring vehicle crash rates (especially serious injuries and fatalities). As I examined evidence-based policing research in this realm, it quickly became apparent there was a glaring lack of rigorous study.

Roughly a decade earlier, the National Highway Traffic Safety Administration had established a popular program to combat vehicle crashes, entitled Data-Driven Approaches to Crime and Traffic Safety (DDACTS). Among the primary tenets of DDACTS (as it relates to tackling vehicle crashes), was the premise of hot spots policing – as it utilized data to target high visibility enforcement efforts in micro-areas where there was a higher propensity of vehicle crashes. Unfortunately, living in a state where 76% of serious injury and fatality crashes occur in rural areas, it was difficult to utilize their established model, or traditional hot spots policing model to identify problem areas. The difficulty was due to the geographic size (roughly 16,000 square miles), and the relatively low sample size of crashes in that vast area. The second problem involved the relatively small number of officers charged with traffic enforcement in that vast area (roughly 75 troopers). The problem we faced as a state is not unlike the challenges the nation faces – with 70% of serious injury and fatality crashes occurring on rural roadways nationally.

A study of vehicle crash causation nationally, by the National Highway Traffic Safety Administration (NHTSA), determined that 94% of significant injury and fatality crashes were the result of human behavior including distraction, impairment, speed, and lack of seatbelt usage. The key to solving this issue – it seemed – was to identify a way to change these four human behaviors to effect significant crash reduction. An approach that caught my eye (specifically considering the lack of human resources to attack this problem) was a method known as the Koper Curve. This strategy – based on the timing of targeted enforcement efforts – determined that the optimal amount of time spent in a hot spot was 15 – 20 minutes. The idea being – to visit a hot spot for 15 to 20 minutes, making your presence known and leaving a lasting residual effect that carries on well beyond your actual presence in the hot spot. This interaction is done in a random and intermittently way, through short interactions, allowing one officer to effect multiple hot spots in one shift (moving from hotspot to hotspot). The essential idea being, “what you do matters.”

If done correctly, an officer can interact in ways that keep people talking about them, even when they aren’t there, so by the time the officer returns for additional interaction, it’s like they never left. These interactions revolve around conversations regarding traffic safety in ways, and at times they aren’t expected. Often they are non-punitive. The resulting ‘ever-present’ perception perpetuates a change in the behavior, as the public expect to see law enforcement when they are traveling – which is a critical element in deterrent theory. Hot spots policing and the Koper Curve had been studied many times in the realms of violent and property crime – proving to be effective nearly every time it was implemented – so why not in the field of traffic safety as well?

With this research as the cornerstone, the Iowa State Patrol and George Mason University’s Center for Evidence-Based Crime Policy partnered to develop a place-based, proactive, and tailored problem-oriented strategy, to increase the perception of law enforcement presence and thus significantly reducing traffic crashes, injuries, and fatalities in Iowa. The project and the associated study (quasi-experiment) began on January 1, 2018, and ended on December 31, 2019.

In order to identify crash patterns, ten years’ worth of crash data were examined to determine potential “hot towns” (near crash sites as probable origin points for drivers involved in fatal crashes along Iowa’s rural roadways). Analysis of data and crash reports suggests that victims of serious injury and fatalities visit these towns, become intoxicated with drugs or alcohol, and then unsafely operate their vehicles (e.g., speeding, seatbelt violations), resulting in the serious injuries and fatalities.

Having identified “hot towns” in each of the counties in the target area, (where 60% of the fatality crashes occurred during the ten year data period) a volunteer team of 16 troopers was selected to undertake the mission of randomly and intermittently making 10–20-minute visits to each “hot town.” While there, they were tasked with engaging in highly visible citizen interactions at specific locations such as bars, gas stations, and convenience stores before moving to the next hot spot. These engagements revolved around serving patrons responsibly, ensuring everyone has made arrangements to get home safely and providing patrons with safety messages, including the importance of wearing seatbelts. The effort also included leaving behind literature in convenience stores and other high-volume citizen areas (specific info on pamphlets regarding the leading causes of fatality crashes, such as distracted driving, operating under the influence of alcohol and/or drugs, seatbelt usage, and speeding). This unique approach to traffic enforcement was both proactive and preventative –not reactive, as most traffic enforcement efforts tend to be.

In an attempt to study the results of this intervention, the activities were closely tracked by each trooper. The data was then forwarded to researchers at George Mason University’s Center for Evidence-Based Crime Policy to conduct a rigorous evaluation of the intervention. The initial intervention period ran for the calendar year of 2018. In 2019, the study continued; however, the goal was to establish a more sustainable model. Therefore, instead of continuing with 16 full-time officers, each of the 75+ troopers were asked to partake in these interactions one hour per duty day.

In 2018, the 16 full-time members of the team completed and tracked over 9600 interactions. In 2019, utilizing a small portion of each day of all available troopers in the area, we were able to complete and track over 34,000 interactions. Although the analysis of the study is still in the early phases, the preliminary results are promising. Within the intervention area during 2018, the overall number of serious injuries and fatalities fell by 7.5%, while the total of alcohol and drug-related serious injuries and fatality crashes fell by 20%. The most significant decrease came in the area of high speed related to severe injury and fatality crashes, which fell by 33% that year. Although an extensive study is still required, we are hopeful the trend will continue into 2019, especially considering the substantial increase in citizen interactions.

Although traffic crashes don’t garner the media attention of other tragic events, their annual impact is significant. Through the implementation and study of this new science-based, multi-faceted law enforcement-citizen interaction, we hope to identify ways to change human behavior to reduce traffic fatalities.


Ken Clary is a captain with the Iowa State Patrol, currently serving as an Area Commander responsible for four district offices, encompassing 28 counties in Northeast Iowa. He is a graduate of the FBI National Academy (269th Session), a National Institute of Justice LEADS Scholar, an Executive Fellow for the Police Foundation, a member of the Center for Evidence-Based Crime Policy Hall of Fame, and Ph.D. Candidate at the University of Nebraska – Omaha.



Leave a Reply