Samenvatting
In this paper, an evaluation is made of the relationship between crashes and various parameters of speed distributions as measured utilizing automatic traffic recorders (ATR) on highways in Iowa. Data on crashes were obtained from the Iowa DOT crash database; speed data are calculated from raw ATR data provided by the Iowa DOT. Standard statistical tests, including the T-test and the F-test, are used to compare the speed distributions as well as their mean and variance. A logistic regression model is developed to explore the relationship between the dependent variable crash risk and the explanatory variables' variance, road type, number of lanes, time of day, and day of week.