If it keeps time, it’s probably just a clock

February 6, 2019

Wendy Parker


Hey, guess what? ELD implementation affected the number of CMV crashes.

No, wait. Hold up. ELD implementation hasn’t changed crash rates.

Oh, but it – wait again. Electronic logging device implementation has likely led to an uptick in CMV crashes. Maybe. On Tuesday of last week, when the road was slick and Mary had a little lamb, there was definitely one half of one percent of an increase in hypothetical crashes of imaginary CMVs.

C’mon y’all.

I’ve read multiple articles about the exact same set of preliminary numbers from an academic study, and it’s been headlined multiple ways.

The only thing I’ve learned that’s positively true about this preliminary data is that it can be extrapolated to whatever agenda you’d like it to follow. Because it’s an estimate, and it’s preliminary.

One thing that held true in each and every piece I read was an abundance of paragraph space dedicated to what was not included in the criteria. You know, the data that might actually set this apart as an empirical study with definitive numbers instead of a pretty fair indication that ELDs are exactly what we said they were from the beginning.

A clock. They’re a gol-dang time-keeping device. Clocks are not a safety features. They’re a billing option. They do not magically control the safety universe. They tell time. The end.

This isn’t the fault of the researchers, nor am I throwing shade at their efforts. It’s important to understand what they actually studied, so further data can include more specific criteria and give more comprehensive numbers across an entire industry scope.

Difference in differences technique (DID or DD). “is a statistical technique that attempts to mimic an experimental research design using observational study data, by studying the differential effect of a treatment on a ‘treatment group’ (post-ELD mandate data) versus a ‘control group’(pre-ELD mandate data).”

This is a really broad net, which is why these studies are sometimes referred to as “estimations.” They’re great for a baseline but not definitive in their findings, because any number of disrupters can affect the overall statistical outcome.

And honey, trucking has an abundance of disrupters when it comes to time-keeping statistical data. Some of those disrupters show up on the Federal Register as exemption requests, and have more to do with the current hours of service than the ELD, but one begat the woes of another and, verily, the problems have multiplied and become legion. (Amen and pass the peas.)

So where we’re at with this particular study is this: the clocks are keeping time. How that affects the safety of the universe requires a gabillion variables to be plugged in the equation before a definitive safety margin is disputed or determined. There’s no doubt HOS compliance is improved, but if HOS compliance equaled safety, there would be no exemptions and the FMCSA would never lift them entirely for emergency relief.

Because that wouldn’t be safe. And this is all about safety, right?


Is this thing on??