There was a study completed in 2001 which concluded from 21 years of data that adjusting our days forward and backwards by one hour increased the number of fatal automobile crashes in the United States. The primary reason for more crashes after the spring forward was the one hour less of sleep that most individuals received.
Interestingly, the reason from the 2001 study for the increase in crashes after the fall back was due to behavioral adaptations, including staying out later in anticipation of the longer day on Sunday. In 2014, a ten year study on the same subject was completed by University of Colorado at Boulder professor that concluded that there is a statistical increase in the number of fatal auto crashes in the 6 days following the spring shift forward.
Considering the long period of time this subject has been studied, it is safe to say that the data does not lie. We should all be careful on the road during these times given the increased number of crashes occurring during the spring and fall daylight savings time shift. Being safer includes taking precautions not to be at fault in a crash but also to be on the lookout to avoid a crash. See the attached study from 2014.