Speed Doesn’t Kill After All

Interesting survey data from the National Highway Transportation and Safety Administration (NHTSA) studying critical factors in traffic accidents. This survey sample of 5,471 crashes studied over a 2 1/2 year period represents a “crash population” of 2,189,166 crashes, involving 3,943,244 drivers and 4,031,226 vehicles.

National estimates generated from the crashes that were sampled show that of all the vehicles assigned a critical reason, about 36 percent were turning or crossing at an intersection just prior to the crash – characterized as the critical pre-crash event. An additional 22 percent of such vehicles ran off the edge of the road, and 11 percent failed to stay in the proper lane. The information pertaining to the crashes at intersections can be used in the design of intersection collision avoidance technologies. The data from run-off-the-road crashes can be beneficial in evaluating the effectiveness of ESC systems. The design of the emerging lane-departure warning systems can be enhanced by analyzing the data pertaining to vehicles that failed to stay in the proper lane.

Turning at an intersection is the most common pre-crash condition in the crashes that were studied, or put another way, you are most at risk of an accident while transitioning from being stopped to moving at a turn. The study broke down primary crash causes as driver related, vehicle failure, roadway conditions, and atmospheric, and not surprisingly driver related factors were the most significant.

Related to cell phones in cars, of the crashes investigated and from which the primary cause was driver error, 41% of those cases were recognition errors and 12% of the 41% were distraction caused by conversation with a passenger or on a cell phone. It’s disappointing that they did not specifically call out cell phone related causes given the focus on this in recent years, but on balance this is not a large number.

Most significantly, speed was a critical factor in only 5% of the crashes, which suggests that higher performance capabilities, prevalence of anti-lock braking systems, and better lighting systems result in drivers operating more safely at higher speeds. Indeed stopped vehicles were more likely to be a critical cause in crashes than speed by a factor of 2 to 1.

Based on my read of this study, it appears that there is a lot of work to be done through technology solutions to address better instrumentation of vehicles (tire and brake failure were significant factors in vehicle related causes) and to address driver recognition issues. As powerful as the human brain is, it is clear from this data that drivers can quickly become overwhelmed while behind the wheel, therefore technology enabling for hazard avoidance, 360 degree visibility, and most significantly, for driver fatigue which is a significant factor in driver related factors.