Maybe That’s Why They Call It the Witching Hour
Posted April 7, 2014
I’m a big fan of data. Not out of a fondness for numbers (I majored in English), but because it is so superior as a starting point compared to anecdotal experience, prejudice, old wives tales, and commonly accepted distortions, the unsavory stew of faulty risk management and misunderstanding that so often guides our actions.
I was intrigued by the following chart (created by Naval Safety Center data manager John Scott). It isn’t intuitive, but it is worth studying.
The jagged blue line is actually the tops of a series bars representing the time at which 881 Sailors and Marines died in off-duty traffic wrecks since FY05. The blue line would match the black line if all of the skidding tires and smashed metal occurred perfectly regularly, like a gruesome metronome, which of course they don’t.
When the blue line flattens (moving away from the black line), it means that the traffic deaths happened much more often. In other words, less time elapsed between the deaths. When the blue line climbs vertically, more time elapsed.
The hours where the blue line flattens – roughly 0200 to 0400 – shouldn’t come as a shock to anyone who tries to keep Sailors and Marines alive on the highway. Time of day (more accurately, “night”) has long been recognized as a potent risk factor.
Who’s driving between 0200 and 0400? A lot of tired and/or drunk partiers and barhoppers who are out there voluntarily, mixed in with some who have to be there because of their jobs and who had better hope their defensive-driving skills are up to par.
The chart is based on an Excel file compiled from the mishap reports about all those traffic deaths. I read through the brief narratives on the Data sheet – if you haven’t had a chance to peruse nearly 900 individual fatalities lately, it is a disturbing experience. This list hints at the actual Sailors and Marines behind the statistics, people who once had careers and families, plans and promise.
This Excel file also includes a “Risk Calculator” that offers six blocks to fill in, based on estimates for the percentage of driving time spent in the time slots. Here’s how I filled it in:
• midnight to 0500, 5%.
• morning commute, 25%.
• the rest of the morning, 5%.
• afternoon prior to the end of work, 10%.
• evening commute, 30%.
• the rest of the evening and night until midnight, 25%.
Here’s how the Excel file calculated the associated risk factors, based on the number of fatalities for those time slots: 664%, 37%, 132%, 92%, 65%, 88%.
Possibly that “664%” leaps out at you. Keep in mind that this is a radically different chunk than rush hour in terms of numbers of drivers on the road, because most stores are closed and most people are home asleep.
Just a little something to keep in mind next time you’re making your plans for a designated driver.