Natural experiments have their uses. Saurabh Bargrava reports his joint work with Vikram Pathania:
…we document a 20-30% rise in cellular call volume during the time of the day– 9pm on weekdays– when cell phone providers systematically transition from "peak" to "off-peak" pricing. We then measure the resulting increase in fatal and non-fatal crashes during this period as compared to weekends and earlier periods which serve as controls. We find no evidence for a rise in crashes, and estimate small positive upper bounds for the effect size at 9pm (~1% for all crashes, and 2.4% for fatal crashes).
Here is the paper. Here is a related press release. You might wonder how this can be reconciled with all those studies showing that talking on a cell phone is as bad as driving drunk. The authors discuss the other work starting on p.8 and score some good points. Furthermore get this:
We confirm our
results with three additional empirical approaches–we compare trends in
cell phone ownership and crashes across areas of contiguous economic
activity over time, investigate whether differences in urban versus
rural crash rates mirror identified gaps in urban-rural cellular
ownership, and finally estimate the impact of legislation banning
driver cell phone use on crash rates. None of the additional analyses
produces evidence for a positive link between cellular use and vehicle
No, I am not encouraging you to talk on your cell phone while driving, if only because so many of you already talk so much, and besides, what if these guys are wrong? But science must progress, and in that spirit I report these intriguing results.