After analyzing video data from roughly 1,700 crashes, University of Iowa researchers determined that “distracted driving contributes to nearly 60 percent of car crashes involving teen drivers” between the ages of 16 and 19. That’s a far higher figure than previous studies have indicated. The findings are significant because although teenagers drive less than most other age groups, “their numbers of crashes and crash deaths are disproportionately high.”

The full report, “Using Naturalistic Driving Data to Assess the Prevalence of Environmental Factors and Driver Behaviors in Teen Driver Crashes,” is available here (pdf). Some highlights are here and after the jump, along with more details about the methodology.

Interacting with passengers in the car and talking or texting on a cell phone were among the most common distractions preceding teen driver crashes. Proposed legislation to ban most cell phone use while driving did not make it through the Iowa legislature’s “funnel” this year, so it’s up to parents to help address the problem by voluntarily not texting or carrying on phone conversations while they drive.

The AAA Foundation for Traffic Safety funded the research by Cher Carney, Dan McGehee, Karisa Harland, Madonna Weiss, and Mireille Raby. After reviewing video evidence from 6,842 crashes over a six-year period, researchers concentrated on 1,691 “moderate-to-severe” crashes.

Of these crashes, 727 were vehicle-to-vehicle crashes in which the force of the impact was 1.0g or greater, and 964 were single-vehicle crashes in which the vehicle’s tires left the roadway and impacted (with a force of 1.0g or greater) one or more natural or artificial objects. While the extent of any injuries sustained in the crashes was not evident from the videos, it is known that no fatal crashes were included in this analysis.

From a University of Iowa press release on the research:

After analyzing the IVER [in-vehicle event recorder] data, researchers were able to determine that attending to passengers was the most commonly seen driver behavior across all crash types, with a driver either looking at or talking to a passenger at some point in the six seconds before approximately 40 percent of crashes with passengers present.

UI researchers say the number of potential passenger distractions increased as more passengers piled in the car; 54 percent of vehicle-to-vehicle crashes had one passenger on board, and 74 percent of such crashes had two or more passengers. Passengers were also more likely to be moving around inside the vehicle and making loud noises as their numbers increased. […]

Though young drivers were most often seen attending to passengers in some way when they were in the car, drivers who traveled alone were most often distracted by cell phone use-the second most frequent behavior observed during the six seconds leading up to a crash.

The study found young drivers used cell phones two times more often when they were alone in the car and texting was observed twice as often as talking on the phone.

From page 4 of the report:

Drivers were seen engaging in some type of potentially distracting behavior leading up to 58% of all crashes examined. The two most frequently seen driver behaviors were attending to passengers (14.9%) and cell phone use (11.9%). Cell phone use was significantly more likely in road-departure crashes than any other type of crash (34% vs 9.2%). Attending to a passenger was slightly less likely to be seen during a road-departure crash than any other crash types (13.3% vs 15.0%). Overall, males and females were equally likely to be engaged in potentially distracting behavior. However, females were more likely than males to have been using a cell phone (14% vs 10%), engaged in personal grooming (7% vs. 5%), or singing/dancing to music (9% vs 6%) prior to the crash. Additionally, for all types of crashes, drivers were significantly more likely to have been using their cell phone when they were alone in the vehicle than when they had passengers.

Drivers were found to have been looking away from the roadway for a significantly longer length of time prior to the crash in road departure crashes than in any other type of crash; mean eyes-off-road times were 4.0s for road departure crashes, 2.5s for rear-end crashes, 0.7s for angle crashes, and 0.5s for LOC crashes. Of all driver behaviors, using electronic devices, attending to a moving object in the vehicle, using a cell phone and reaching for an object resulted in the longest mean eyes-off- road times (3.9s, 3.6s, 3.3s, and 3.3s, respectively). Drivers engaged in cell phone use had mean eyes-off-road times that were twice as long as those drivers who were attending to passengers (3.3s vs 1.5s). Also, when cell phone use was analyzed separately, the average eyes-off-road time for drivers who were operating or looking at their phone was 4.1s, compared to 0.9s for drivers who were talking or listening.

Reaction time was analyzed for rear-end crashes only. Results found that drivers who were using a cell phone had a significantly longer reaction time than drivers not engaged in any behaviors (2.8s vs 2.1s). In contrast, drivers attending to passengers had similar reaction times to drivers not engaged in any behaviors (2.2s vs 2.1s). In addition, in over 50% of rear-end crashes where the driver was engaged in cell-phone us, the driver showed no reaction at all (braking or steering), whereas the driver failed to react at all in only 9.5% of crashes with a driver attending to a passenger.

Here’s the short summary of the research methods used:

Lytx, a company that has been collecting data using in-vehicle event recorders (IVERs) for over a decade, provided the crash data. Their DriveCam system collects video, audio and accelerometer data when a driver triggers the device by hard braking, fast cornering, or an impact that exceeds a certain g-force. Each video is 12-seconds long, and provides information on the 8 seconds before and 4 seconds after the trigger. The system has a wide range of applications-families use them to help young drivers as they begin to drive independently, while over 500 commercial and government fleets employ them for fleet management.

Crashes examined in this study involved drivers aged 16-19 who were participating in a teen driving program that involved the use of a DriveCam system. Ltyx made 6,842 videos of crashes that occurred between August 2007 and July 2013 available for review. In order to reduce this number and to eliminate minor curb strikes from the analysis, those crashes in which the vehicle sustained forces less than 1g were excluded. Crashes in which the DriveCam equipped vehicle was struck from behind were excluded. Additional videos were excluded for other reasons (e.g., animal strikes, video problems, or the driver not being a teen). A total of 1,691 moderate-to-severe crashes met the inclusion criteria and were analyzed for the current study.

Video from the 6 seconds preceding each crash were coded for analysis. A coding methodology which focused on identifying the factors present in crashes was developed specifically for gathering information from the videos. Data elements coded for each crash included environmental conditions, contributing circumstances (e.g., inadequate surveillance, running traffic signals), and driver and passenger behaviors. Each crash was double coded by two University of Iowa (UI) analysts and mediated by a third when necessary.