In case you haven’t already noticed, the speed limits for trucks on interstate highways has increased in Ohio from 55 MPH to 65 MPH. This was included as part of the new transportation budget.
Trucks allowed to speed up in Ohio
By Celeste Savage • CelesteSavage1@gmail.com • June 30, 2009
COLUMBUS — Starting Wednesday, state law allows most trucks to go 65 miles per hour on many of Ohio’s interstates.
It’s one change to Ohio traffic laws that the state legislature approved as part of the transportation budget three months ago.
As a part of House Bill 2, Ohio lawmakers increased the speed limit for large motor vehicles and non-commercial buses from 55 mph to 65 mph.
The change applies only to interstates — not U.S. Routes, State Routes or other multi-lane divided highways – where speed limits currently are split between 65 mph and 55 mph.
It is expected that all speed-limit signs will be changed by July 2, without the need for paying Ohio Department of Transportation workers overtime. They’ll be placing white reflector material over the 55 mph part of the signs
While the new speed limit will undeniably save time for truckers, there have been some concerns about safety of the measure. There has been research on the relationship between speed and crashes that suggests speed differential may be more closely related to crashes than actual travel speeds. See the following excerpt from Managing Speed: Review of Current Practices for Setting and Enforcing Speed Limits:
Although the evidence is not conclusive, speed appears to contribute to crash occurrence. Theory, empirical data drawn from correlational studies, and causal analyses of crashes provide evidence that both speed and speed dispersion are associated with crash involvement. Crash involvement rates rise as a function of speed for certain crash types, such as single-vehicle crashes. Deviation from the average traffic speed is also associated with crash involvement. At high speeds, deviation from average traffic speeds not only increases crash probability but also the risk of a severe crash because of the close link between speed and injury severity discussed in the following section.
Limited data are available to analyze speed-safety relationships by road class. Deviation from average traffic speeds appears to play a role in crash involvement on Interstate highways, particularly near interchanges on urban Interstates, and to a greater extent on rural nonlimited-access highways where high vehicular speeds and poorer road design combine to increase crash probability. Less is known about the role of speed and speed dispersion on urban roads.
So I expect that the number of crashes could actually decrease by setting the truck speed limit equal to the passenger vehicle speed limit. On the other hand, the average severity could increase. The same report notes the following:
In summary, all of the studies that have investigated the link between vehicle speed and injury severity have found a consistent relationship. As driving speed increases, so does the impact speed of a vehicle in a collision. Increased impact speed, in turn, results in a sharp increase in injury severity because of the power relationship between impact speed and the energy released in a crash.
If I’m right, will lower crash rates and faster travel times make up for higher average crash severity? I definitely haven’t done enough research on the issue to decide that with any certainty.
Does anyone have any anecdotes out there about your experiences on the road with the now faster-moving trucks?