Evaluating safety effects of Daylight Saving Time on fatal and nonfatal injury crashes in Texas. Safety Data, Analysis, and Evaluation

Daylight Savings Time (DST) takes place each year from 2:00 AM on the first Sunday in April to 2:00 AM on the last Sunday in October. It is expected that the changes to and from DST could affect safety, as regular daily routines the road users are accustomed to change abruptly. In fact, past research conducted on the investigation of these effects has shown that the change to and from DST either has a positive or negative influence on safety. Similarly, some of the previous studies suffered from methodological limitations, including erroneous extrapolation of short-term effects to long-term conditions. Given these limitations and opposing results, there is a need to reexamine the effects of DST on the number of motor vehicle and pedestrian crashes. The primary objective of this study was to quantify the safety effects of DST through the use of statistical modeling for the morning and afternoon 5-hour periods, at the boundary delimiting dark and light conditions which has the most important effects on safety. The secondary objective consisted of conducting a before-after study to estimate the immediate effects following the change to and from DST. To accomplish these objectives, fatal and non-fatal injur