Speeding is reported in the Fatality Analysis Reporting System (FARS) as a driver-level attribute that combines “driving too fast for conditions" or "in excess of posted speed limit.” There is a growing need to parse out these two factors, especially for those designing countermeasures. The report, using data from the State Data System quantifies the extent of these two aspects related to speeding using data from six States whose police accident reports actually parse these out. The result of this analysis shows that this really depends on the severity of the crash. In fatal crashes, about 55 percent of all speed-ing-related crashes were due to “exceeding posted speed limits” as compared to the 45 percent that were due to “driving too fast for conditions.” The comparable percentages for speeding-related injury crashes were 26 percent versus 74 percent and those for PDO (property-damage-only) crashes were 18 percent versus 82 percent. The second aspect examined in this study is how these crashes, which related to the factors “driving too fast for conditions” or “ex-ceeding posted speed limit,” were affected by roadway environments. It shows that the speeding-related crashes that were due to “driving too fast for conditions” were more likely to have occurred on roads with higher speed limits (50+ mph) as compared to other crashes. Roadway environments analyzed also include: roadway surface conditions, roadway alignment, and intersec-tion/intersection-related roadway segment. (Author/publisher)
Samenvatting