State Reports Show Speeding Not a Significant Cause of Accidents Analysis of data from twenty-five states confirms exceeding the speed limit is not a significant cause of accidents.
Out of 2.7 million traffic accidents recorded in twenty-five states over the course of a year, only 1.6 percent were caused by drivers who exceeded the posted speed limit. The figures come from an analysis by TheNewspaper of annual reports typically compiled by each state for use in applying for grant money from the National Highway Transportation Agency (NHTSA).
The US Department of Transportation has specific programs encouraging states to boost the number of citations issued as a prerequisite for receiving additional federal funding. Rhode Island's fiscal 2012 application to NHTSA, for example, sets the following goals: "To increase the number of speeding citations issued during grant-funded enforcement activities from 5,802 in 2011 to 6,000 in 2012" and "To increase the number of speeding citations written and tracked monthly for all overtime speed patrols."
Speeding tickets are a multi-billion annual business for state governments, municipalities and the insurance industry. Politicians seeking to justify the the issuance of so many citations frequently turn to statistics that show that "speeding" is the among the most common causes of traffic collisions in the United States. In twenty-five states, ten percent of all accidents can be considered "speed-related" -- yet this does not mean that the cars involved were actually exceeding the speed limit in every case.
Most state accident report forms ask the investigating officer to determine whether the collision was caused by a driver exceeding the posted speed limit, or if a driver was under the limit but in excess of the speed prudent for the weather and road conditions. Half of the country reports these factors separately. The other half conflates these very different categories under the heading of "speed-related" accidents. This allows state officials to speak about the "speeding" problem by including accidents that did not involve individuals who exceeded any limits. In fact, Tennessee found 103 accidents were caused by driving too slowly in 2007. Kansas showed 102 accidents in 2008 were caused by impeding traffic.
Utah provided the most complete breakdown of speeds for the 49,368 reported collisions that happened in 2010. Of these, 9 percent were traveling under the posted limit but too fast for the conditions. Another 2 percent were traveling at the speed limit, but too fast for the conditions. Only 3 percent of accidents were caused by drivers exceeding the legal limit by 10 MPH or more.
A 2009 NHTSA study examined the same question and found that 12.8 percent of accidents were "speed-related" in Kansas, Kentucky, Maryland, Montana, North Carolina and Wisconsin from 1998 to 2004. Of the "speed related" collisions, 78 percent were caused by driving too fast for conditions and 22 percent exceeded the posted speed limit. The data suggested that weather is the most significant factor for drivers who went "too fast" without exceeding the legal limit.
"In speeding-related crashes (driving too fast for conditions), a higher proportion of crashes occurred on adverse road surface conditions ('Snowy/Slushy/Icy-slippery' and 'Wet') during cooler months (December to March), as compared to other crashes," the NHTSA report found. "This could partially explain the fact that speeding-related crash fatalities, as a percentage of the total fatalities by month, are higher in cooler months. In the winter season and under adverse road surface conditions, it could be easy for a vehicle to exceed a safe travel speed (this safe travel speed might need to be lower than the posted speed limit)."
A copy of the contributing factor report excerpts is available in a 2.5mb PDF file at the source link below.