85 mph Speed Limit for the “Good Of the Republic”… Otherwise known as the Texas DOT.
Wayne Gerdes - CleanMPG
- Sept. 10, 2012
85 mph = 10 to 20 mpg depending on what vehicle is being driven. In the Great State of Texas, that means pickups and 10 mpg will be wishful thinking. $4.00 per gallon and 8 mpg… That is like throwing a dollar out the window every 2 miles
The Texas Department of Transportation (TxDOT) has officially approved an 85 mph speed limit for a 40-mile privately funded stretch of Texas 130 from Austin to San Antonio. According to Wiki, the 85 mph posted speed limit (PSL) will earn the title of the fastest legal speed limit posted anywhere in the Western Hemisphere.
Here is how it happened
The 41 miles of toll road that the 85 mph limit is being implemented is being built by a private consortium led by Spanish toll road firm Cintra. The firm spent $1.3 billion to design and build the road and collect the tolls on the road for 50 years, though TxDOT does retain ownership of the actual highway. Under the TxDOT/Cintra contract, the firm contractually agreed to pay TxDOT $25 million up-front as construction began. Depending on the speed limit set by the Transportation Commission this year, the company would be contractually obligated to pay $67 million if the new road received an 80 mph PSL. If the road received an 85 mph speed limit, TxDOT’s bonus would be $100 million USD paid up front and in full.
So what do you think the PSL was going to be set at?
According to the TxDOT’s own unapproved methods for setting an interim PSL, a TxDOT engineer drives the as yet unopened road without looking at the speedometer and someone else notes his or her speed. The speed limit is then set at something close to the speed that the engineer drove.
The commission of course allowed an 85 mph posted limit in order to maximize its revenue stream. In this case, a $100 million one-time payment!
Fortunately permanent limits are set using a bit more study including 125 drivers under actual driving conditions. The limit is set near a speed that 85 percent of the drivers are at or below during the study.
We will see if the 85 mph limit holds after the final study is completed. If not, TxDOT has to refund some of the windfall.
A little “Funny” math
There are three things that add up to total stopping distance: Perception Distance + Reaction Distance + Braking Distance = Total Stopping Distance.
The average person’s perception and reaction time is approximately 2 seconds before he or she would actually apply the brakes in a situation that could use every inch of stopping distance to prevent an accident. At 55 mph, the average driver has covered 161 ft. or more than half a football field before brakes have actually been applied.
A modern automobile in a panic stop will come to halt from 55 mph in approximately 125 ft using the following formula:
Braking distance = (Initial velocity)**2 / (2 * coefficient of friction * 32), where the coefficient of kinetic friction between the tires and a dry road
is approximately 0.8.
Adding them up, you have 285 ft. to stop and this is from 55 mph.
Now let’s do the same at 85 mph. In 2 seconds at 85 mph, the average driver has covered 249 ft. or 83% of a football field before
they have touched the brakes. Add another 300 ft. from the formula above for the actual stopping distance and you are out 550 ft. or almost double what it took to stop from 55 and closing in on two football fields!
Earlier today the American Trucking Associations today urged the Texas Transportation Commission to reverse its decision to allow vehicles to travel 85 miles per hour on a privately-managed stretch of State Highway 130 linking Austin and San Antonio, and cautioned other states against following the Lone Star State's dangerous example.
ATA President and CEO Bill Graves:
"At the end of the day, excessive speed is the greatest threat to highway safety. And by giving motorists carte blanche to put the pedal to the metal, Texas is raising the risk of more crashes, as well as more severe crashes."
The American Trucking Associations has been vocal about using technology to regulate maximum truck and all vehicles speeds to 65 mph.
On today’s busy and congested highways, it is simply unfathomable that a state would allow drivers to put themselves and others at risk by increasing speed limits to such excessive heights. The state's obvious attempt to generate more profit for itself and private investors comes at the public's expense.
Heaven help us ever thinking about our foreign oil dependence with stupidity like this running around. Isn’t this where Rick Perry is the current and George W. Bush was the former governor?