Trucks, Traffic & Safety

13. December 2013

“Sin ¼ biXin þ ein ð1Þ
where Sin is the function that determines the probability of
discrete outcome i for crash observation n, Xin is a vector
of measurable characteristics (highway geometric features,
environmental conditions, driver characteristics,
etc.) that determine the injury severity for crash n, bi is a
vector of estimable coefficients, and ein is an error term
accounting for unobserved effects influencing the injury
severity of crash n.”

That is from “Identifying the factors contributing to the severity of truck-involved crashes” by Chunjiao Dong, Stephen H. Richards, Baoshan Huang & Ximiao Jiang, which appears in the International Journal of Injury Control and Safety Promotion.


No, we don’t know what that equation means, nor can we follow many of the others that are found within the paper.

But there are some things that we do get.  Like that trucks (i.e., gross vehicle weight >10,000 lb) carry 70.7% of all freight in the U.S. by value, 68.8% by weight, and 39.8% by ton miles.  Or that trucks are essential for the flow of goods.

However, while trucks constitute just 4% of all of the registered vehicles in the U.S., and travel 8% of the total miles driven on public roads, they are, according to the authors, “involved in 11% of all passenger vehicle occupant deaths and 70% of those killed were riding in passenger vehicles at the times; an additional 14% were on foot or bicycles.”

We don’t even want to think of the consequences of those pedestrians or bicyclists tangling with a a >10,000-lb GVW vehicle.

So what do we know from this rigorously detailed paper?

That trucks are essential for the transport of goods.

That trucks can be disproportionately dangerous/fatal when it comes to accidents.

But one finding was rather surprising, and should be taken into account when on the road: “Truck-involved crashes on the roadway with lower traffic volume noticeably increased the probability of fatality.”  That’s right: the less traffic on the road, the greater the likelihood that a fatality will occur as a consequence of an accident with a truck.  Why?  The authors posit that when there is less traffic, speeds go up, and as speeds go up, the physics can lead to fatalities.

And as much of the U.S. is experiencing snow, ice and cold weather, know that the authors found that weather plays a roll in truck-related fatalities.

Whether you’re in a truck or a car, walking or on a bike, be careful out there.