Utah’s Experimental Speed Limit Increase Deemed Successful
According to TheNewspaper, the Utah Department of Transportation, which raised speed limits to 80 miles per hour on certain stretches of I-15, reported no downside to the experimental increase.
The UDOT selected stretches of road to increase the speed limit by five miles per hour based on crash histories. After watching and evaluating these roads, they discovered very little increase in actual speed.
“With the speed limit posted at 75 MPH, 85th percentile speeds measured between 81 and 85 MPH -- barely different from the 83 to 85 MPH speeds under the higher 80 MPH limit. The 85th percentile speed represents the speed at which 85 percent of free-flowing traffic feels is the safest. Engineers have determined that the greatest safety can be achieved when speed limits match the 85th percentile speed.”
So far, the UDOT is declaring the experiment a success, and will continue to monitor the interstate, meanwhile evaluating the future of other roads.
We are also pleased by this news, and hope to see this program expand to other parts of the country that could benefit from such experiments. We also want to know what you think. Would you support this experiment on your highways? Talk about it in comments.
+ TheNewspaper: Utah DOT: No Downside to 80 MPH Speed Limit Increase
via: The Truth About Cars
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Comments
ben
It depends on how congested the roads are. I personally think 80 mph is too high.
bakerzdosen
Well, I'm going to disagree with the first comment. If you've ever driven that stretch of interstate (between Beaver and St. George) there is a whole lot of nothing in that area (hours of it actually.) People really do routinely drive 90-100mph in that area.
As a Utah resident who was sorely disappointed my Opel rental car wouldn't go over 193kph (roughly 120mph) last week on the Autobahn, I can tell you that 80mph is not too fast for that road. Personally, I'd love to see the speed limit removed entirely in areas that remote and let people use (gasp!) common sense to determine their speeds.
Not many people here think about gas mileage at all when determining their highway speeds, but believe me, you think about it at 250kph+. Too much of the responsibility of driving has been taken from us and legislated.
(FWIW, I'm absolutely for strict enforcement of speed limits in residential areas.)
mark_jensen@und...
German drivers on the Autobahn are different than US drivers. You have likely gotten advanced driver instruction and are a capable driver. However, training in the general US driver population is non-existent resulting in 40,000 deaths each year. Speed limits on interstate and other highways could be removed if US drivers had the training and understood their vehicles. Interstates in particular are designed for speeds twice the current posted limits.
I concur that speed limits in residential areas are good.
tshea
I think that the 85th percentile guideline should be tried on all highways. It might in fact make them safer. My guess is that on more congested highways, the 85th percentile speed will be below the 83 - 85 mph measured in the Utah experiment. Personally, I find 80 mph to be a very comfortable speed even on highways here the NJ/NYC metro area when traffic permits. I think the biggest difference between German drivers and U.S. drivers is that most American drivers don't adhere to the keep right/pass left rule. There are many reasons for that, I'm sure, but I believe that many here in the U.S. have never heard of the concept. They see the left lane as just another travel lane.
racemup321@aol.com
Chuck Fasst
If we could just get the States and local agencies to stop treating speed limits as revenue generating tools, it could certainly work. But that will never happen - too many jobs depend on that revenue stream. :-(
bluzfrek
On a recent trip down IH-10, between San Antonio, Texas, and Ft. Stockton, Texas, the allowable speed limit was 80 MPH, and while I tried it for a few miles, I noticed the average MPG readout on the trip computer took a pretty good hit; when I backed off to a more economical 73-74 MPH, the computer showed a very respectable 27 MPG - not too bad for a Mercury Grand Marquis, eh??
foremostcarguy
I think that speed limits are terrible, and generally are not enforced at all. I drive 2 highway style roads to work. One has a posted limit of 45mph, though commonly cars are going 65-70 on this road, passing "speed traps" that do nothing. The next section is an interstate with a posted speed limit of 55, common speed is 70-80.
What is the purpose of a low speed limit if it is not enforced? It doesn't even serve as revenue then, except at the officer's discretion. Also it causes a safety issue when some cars still obey speed law and insist on driving 55mph, while others drive 80+ on a 2 lane road with heavy traffic. In general limits need to be raised, or enforced.
I've also driven accross the west, Nebraska, Wyoming, Utah, Nevada. Been accross the country on I-80, and there are plenty of places where the road and traffic conditions make speed limits unnecessary. I remember a particular portion of I-80 in Utah near the "salt flats" that offered no curves for over 40 miles, and very very little traffic in that area either.
Regarding fuel economy, cars are primarily designed to operate within a certain speed range. Generally I believe the peak is in the range of 30-40mph, and I expect you would find this is about the average driving speed. Average speed on the computer in my STS over the last 8,000 miles is in this range. Also, since until recently the highest posted speed limits were 70-75 I doubt many cars were designed to offer peak efficiency at speeds higher than this. Another worthwhile note especially on that Grand Mark is that it has a 4 speed transmission. Newer generation cars are offering 6+ gears which allows a great range of "peak" efficiency.
http://foremostcarguy.blogspot.com/
mjhawkins2346
People will drive at the fasters safe speed based on their own perception.
Limit signs are merely an opportunity to potentially force unusual behavior or provide a rich ticketing environment for the police.
If you want slower traffic make the lanes narrower, winding and the pavement bumpy.
At least Utah is accepting the realities of life and driving behavior - even if they are backing into it....
M
"If you think nobody cares, try missing a couple of payments."