A Bucketful of Dollars for a Fistful of Lives … And Supertankers of Oil
 

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 :rolleyes:

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!

Others Ideas

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:
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?

Re: A Bucketful of Dollars for a Fistful of Lives … And Supertankers of Oil
 

Well, they really might as well just do away with the speed limit. I mean, at 65mph, people are already traveling at 80mph plus. Maybe you should involve those most likely scenarios in your calculation as an addition to show what these people are actually getting? Would this be cause for the epa to revisit its standards due to people travelling at slightly above legal speeds not getting the fuel efficiency figure printed on the tag?

That said, I hope it's a wide road and very well segregated for drivers traveling in opposite directions. Otherwise, a 200mph crash (enough force generated here to lift a boeing 747) will not be a pretty sight.

Re: A Bucketful of Dollars for a Fistful of Lives … And Supertankers of Oil
 

Yee Haw!!! I want to setup a law firm on this stretch of hwy so we can be on tbs scene quick if there are any survivors. Anyone want to be a partner?

If the PSL is 85mph then you know 100mph is the real limit just like 65mph is 80mph haha.

I was being shunned, like what wtf are you doing, going 75mph in AZ?

Any blow out or lockup and your DONE! A blow out at 65mph is scary as hell! Let alone 85mph+

I guarantee will see some crazy videos on live leak! Stay tuned!

Here is something that happened very close to where I live

211.43.148.144/10001/26B56/UNKNOWNLSN_00000051.3gp

Re: A Bucketful of Dollars for a Fistful of Lives … And Supertankers of Oil
 

It's sounds like a tourist attraction for people who want to speed or atleast test how fast their cars can go. At 41 miles - this high speed joyride won't last longer than 30 minutes. Any vehicular accidents over 85 mph will likely be fatal and there probably won't be much left after the impact. It wouldn't work in DC Metro Area - because we'd end up with a traffic accident clogging up the road on a daily basis and everyone on the road would be crawling at 10 mph around the wreckage with the traffic backed up for miles... AllState Insurance rated the drivers of the Washington DC Metro Area as the worst in the nation - a badge of distinction I'm afraid we truly deserve ...(9_9)

Re: A Bucketful of Dollars for a Fistful of Lives … And Supertankers of Oil
 

wow! you guys must have been REALLY freaking when Montana got rid of their PSLs (at least for a little while) on the main freeways....

i won't ever be driving in TX so it doesn't bother me much. nothing i can do about it. i'll just enjoy the slower paced roads around here.

Re: A Bucketful of Dollars for a Fistful of Lives … And Supertankers of Oil
 

As far as safety - roads and modern cars are pretty darn safe. Look at the annual fatality numbers over the last 5 years. Absolutely shocking improvement. Remove the fatalities from impaired drivers and it is pretty hard to argue that a modern limited access highway at 85 mph is a particular problem.

As far as division from opposite direction, I don't know the particular road but when was the last time a modern high speed road was built with any possibility of a head-on collision? Heck around me, every 45 mph new road has dividers or a blanket of trees.

As far as FE, the real problem is the continued lack of aerodynamic design. Sure it is getting better but we really should embrace true aero if we want to go 85.

Time spent in a car is unproductive time. If you can reduce it....

Re: A Bucketful of Dollars for a Fistful of Lives … And Supertankers of Oil
 

Google is your friend. Looks like the road is well constructed for such speeds. Not that such speed is safe, but the road itself won't be the hazard.
https://maps.google.com/maps?q=Austi...o+san&t=h&z=18

Re: A Bucketful of Dollars for a Fistful of Lives … And Supertankers of Oil
 

The planet will not be saved until fuel is rationed*.. you want to drive at 85mph?, get a few solar panels and a Tesla S.. or compost your poop and run a genset with the methane. Better if you just walked or rode a bamboo bicycle.

* I'm just channeling some the green, crankier highly seasoned members

Re: A Bucketful of Dollars for a Fistful of Lives … And Supertankers of Oil
 

Ditto on the tourist attraction aspect of the road. Sorry but there isn't much difference between 70 mph and 85 mph. At forty one miles, it isn't much of a big deal as far as time savings go. 38 minutes at 65 mph, 35 minutes at 70 mph, 29 minutes at 85 mph. :rolleyes:

So you're saving a whole six minutes over 70 mph and probably losing an additional five miles per gallon between seventy and eighty five. At ($4.00 per gallon) $8.20 in gas at 70 mph vs $10.93 or spending an additional $2.75 in gas to save six minutes. In other words spending $27.50 per hour in additional fuel for the privilege of driving 85 mph in your pick up truck or SUV.

Yep they are defiantly aiming this "toll" road at the mathematically challenged.

Re: A Bucketful of Dollars for a Fistful of Lives … And Supertankers of Oil
 

By the way, the road is a bypass around Austin. It splits off of I35 well north of Austin, and joins back in south of the city. It's not really on the way to San Antonio unless you're starting on the far side of Austin. (or going from north to south within Austin)