Weekday and time of fatal road crashes in the USA

Interactive Visualization

Link to the interactive visualization (big screen recommended):
Date and time of fatal crashes in the USA.
Below you'll find static pictures of the visualization and a quick analysis.


  • Press 's' to swap the primary and secondary x axis (days and hours)
  • Press left/right arrow to go to previous/next year respectively.

Data & Tools Used

Data source: Fatality Analysis Reporting System by the NHTSA.
Preliminary data manipulation with sed and other shell tools, visualization created with d3.js, using queue to load asynchronously the tsv files.

Quick and Dirty Analysis

Weekday and time of fatal crashes in the USA

  • During the span of 20 years, the distributionof of fatal crashes across the week has remained basically the same.
  • There has been a noticeable fall in the number of crashes from 2006 to 2009
  • The hours with more crashes is 15.00-18.00, except for the weekends when there is a big rise in fatal crashes during the night (21.00-06.00)
  • Keep in mind that you really can't say anything about "safety" from this data/visualization alone.
    For example you may think, looking at the visualization, the "safest" time to be on the road is on weekdays nights, with less than 400 fatal crashes per year, while all other time period are well over 500 fatal crashes per year. But that's moot without considering the amount of "traffic" in the time period. If on weekdays nights there are 80% of fatal crashes than on saturday night, but only the 1% of the traffic, it's actually more dangerous to drive.
    Also, all of this is probably negligible if we consider other security factors: wheter you're sober or not, speed, drowsiness etc.