Overdrive Extra

Max Heine

Safety and fuel economy at 85 mph

| October 25, 2012

Two things come to mind about the Texas stereotype: big and independent. Both are at work in the new section of toll road that opened Wednesday with an 85 mph speed limit, the nation’s highest.

The remaining 41 miles of the SH 130 toll road run from just south of Austin to an intersection with I-10 northeast of San Antonio. The toll road’s intent is to provide relief for a highly congested part of I-35. The private project will bring $100 million to the state.

Because the 85 mph limit raises safety questions, the national media has ignored the state’s familiar slogan: Don’t mess with Texas. Reports often note that 85 mph exceeds hurricane winds. They also cite the Insurance Institute for Highway Safety, which argues that as speed limits rise, so do fatalities. Many studies, not to mention common sense, bear that out.

Realistically, though, the new road might have a honeymoon period of low volume and relative safety.  “I would expect over the years, when the congestion increases on the toll road, TexDOT will re-evaluate that speed limit,” says John Esparza, president and CEO of the Texas Motor Transportation Association.

Trucking’s perspective hasn’t gotten much coverage. Most of the bigger carriers in Texas, as elsewhere, govern their trucks around 65 mph. That creates a 20 mph difference between trucks and every other vehicle on SH 130. “That’s a safety concern that companies don’t like to put themselves in the middle of,” Esparza says.

Given the toll, safety worries and the inability or unwillingness of many truckers to drive 85 mph, heavy-duty trucks could be underrepresented on the new part of SH 130.

This will disappoint four-wheelers who stick to I-35, hoping to see big trucks migrate to the toll road, and don’t realize why trucks often drive slower than  everyone else. They don’t know that a 10 mph reduction at highway speed improves a truck’s fuel economy by a full mile per gallon.

Not so with cars. A similar reduction yields only a 1 percent fuel savings, at best. Some studies show certain models actually get better fuel economy at a higher speed. So even $10-a-gallon gas would not make Texas motorists reconsider zipping around at 85 mph.

That’s probably for the best, as far as trucking goes. Esparza notes that SH 130 seems to be aimed more at the commuting public. Let’s hope that it draws plenty of four-wheelers and makes I-35 a little more tolerable for commercial drivers.





  • jescott418

    With the toll I am sure Texas is thinking the trucks will stay on I35. I suspect that will be true. Its 40 some miles. Do we really need 85mph for 40 miles? My concern is not only inattentive drivers but also bad tires, impaired drivers and the added cost not only in fuel but in tolls. One has to ask, is it worth it? I guess we will find out.

  • http://www.facebook.com/jrreul Jim Reul

    If a trucker feels he doesn’t want to go 85mph he has the right to not have to travel that road. Jezz isn’t the free market a great idea.

  • http://twitter.com/TruckingJames James N.

    Better idea, set a minimum speed for any vehicle by lane, and the 65MPH turtles can stay right and let those of us who WILL run the speed limit do so without having to sit behind those slugs, instead of cramming us all into the right 2 lanes, and forcing the faster trucks to sit behind the snails.
    …if you are a snail, STAY RIGHT!
    I HATE 35 now for that VERY reason.
    3rd lane laws are STUPID.

  • http://twitter.com/TruckingJames James N.

    …and yes, if it means paying a toll to avoid having to tolerate more INSIPID ATA trucks, SIGN ME UP!
    I’d HAPPILY run 80.

  • ldmff

    Everything is big in Texas but, I guess they’re not big on fuel mileage. Why didn’t they just add some extra lanes to I-35 instead of building and entirely new road equipped with toll booths and employees. There aren’t many trucks these days that will run this kind of speed anyway. I can’t for the life of me figure out how many states have raised their speed limits when on the grand scheme of things we’ve been pushing for better fuel mileage and safety…..Oh well go figure!

  • http://www.facebook.com/john.forker.79 John Forker

    A MEN, if you can’t run with the big dogs, stay on the porch !! keep your ata ideas and cry baby attitude out of TX !!

  • R S HAMMER Trucking

    I say yes to 85 and I think Texas is right.

  • Thomas

    Just like when the speed limit was 55 nationwide people will drive the speed they are comfortable with and the highway is designed for.In west Texas in a 80 mph highway trucks have more sense than going any faster than they do anyway(tires!).They never slowed down unless a cop was present back then,but all the makers of the 55 saves lives bull still tried to say it was saving lives.

  • http://www.facebook.com/ztbell Zachary Bell

    The Texas DOT can’t make 35 any wider than it is now through Downtown Austin. A cemetery is on one side and a major university- the University of Texas at Austin- is on the other. Both are protected by state eminent domain laws and the part of 35 in this area has already been made into a double-deck freeway with 4-5 lanes in each direction. They had no choice but to build a new toll road for some of the through traffic (e.g. trucks going to the Caterpillar plant in Seguin and cars going to the east side of San Antonio and I-10 east). Worse yet, cars are the main cause of congestion on this stretch of road and always try to avoid paying a toll, so an 85 MPH speed limit on a bypass that connects I-35 to I-10 is actually an incentive for them to get off of 35. Texas is clearly wanting trucks to stay on 35 and cars to get off.

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