80 MPH
The speed limit for 521 miles of Texas’ Interstate highways has been raised to 80 miles per hour.
Before it was 75 MPH, so Texas was already higher than Illinois. As is Indiana's on at least its tollway.
When I ran for Governor on the Libertarian Party ticket, I advocated raising the speed limit to 65 MPH on two-lane state highways—what it was before the gas crisis of the 1973—and 75 MPH on Interstates.
Indeed, the speed limit on the tollway was 75 MPH outside of the six-county area until Governor Jim Edgar decided that was too fast.
Raising the speed limit still makes sense. Interstates were designed for 80 MPH, I’ve been told.
More non-Left-Stream articles at McHenry County Blog.
13 comments:
The maximum design speed for interstate highways in Illinois is 70 miles per hour. The interstates were built in the early '60s and usually do not meet today's design criteria. So driving at 75 mph or 80 mph is driving at speeds beyond what the road was built for.
IDOT "B Team"
Thanks, IDOT "B Team."
What was I-39 designed for?
They are designed for 30,5,30,5,30,5,80. I truly believe you can go 10mph over the limit or faster, as long as you are not driving like a moron.
The interstates and tollways in IL were not designed for 70 mph, the roads were designed for 75 mph for cars built in the late '50s and early 1960s (when most cars didn't have seat belts). Prior to 1974 most interstates and tollways in IL had limits of 70 mph. With the safety improvements made in automobiles, buses and trucks since 1974, not to mention mandatory seat belt laws, the limits on interstates and tollways should be at least 70 mph. In addition, Texas' 80 mph limit is still lower than the 130 km/h limit in most of western Europe.
Anon
If my back of the envelope calculation is correct -- 130km/hr is equal to 80.77 mph. Big difference.
Cal
If you drive I-39 in the winter time, my prayers are with you.
Thankfully, I don't have to do that anymore.
Maybe I am not following you.
Are you claiming that because people ignore a law, it should be repealed?
Hmm, raising the speed limit when gas prices are higher than ever makes a lot of sense!
Oh I know, you can still drive under the speed limit, but that is hard to do when folks are riding up your rear bumper.
think: have you ever driven on a Houston freeway during rush hour?
=:-O
:-)
Whne set properally Speed limits are set by the government clocking the normal flow speed of traffic in a given stretch of highway to find the natural flow speed . The 85th percentile is what traffic engineers use to set speed limits .
Then the closest speed close to the natural flow speed . This is how it was done until the Mandated 55 was forced on the US . which never had any effect on the speed traffic flowed . And was only a money generator for state & local governments and never had any positive effect on safety .
Setting a speed limit above or below the normal flow speed ( 85th percentile ) is a waste of time and has no effect on the flow speed . And often makes a given stretch of road more dangerous to drive on .
So yes the limit should be set by the speed people drive . If 65 is too slow a investigation of the nornmal flow speed ( 85th percentile ) should be done and the limit should be raised accordingly .
Metro speed limits on the rise
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G as prices have been going up in the Metro area and guess what: So are speed limits.
After months of study by the Michigan State Police and the Michigan Department of Transportation, speed limits are being raised from 55 mph to 70 mph on selected portions of major freeways in southeastern Michigan.
The rise in speed limits pretty much reflects the pace that motorists already are driving in Metro Detroit, according to First Lt. Thad Peterson, commander of the Traffic Services Section of the Michigan State Police.
"We've been working on this for quite a while now," Peterson said.
"The basic reason is so we have maximum uniformity of traffic patterns on the freeways. When we have traffic patterns that aren't uniform, you end up with conflicts between vehicles. That conflict can result in crashes. Sometimes you have to raise speeds to reflect actual driving conditions."
The best way to do that, according to Peterson, is to raise the speed being driven by drivers trying to abide by the limit.
"Potential problems arise when someone is trying to abide the law by driving at 55 mph when everyone else is driving at 70 mph," Peterson said. "Raising the limit allows them to drive at the same speed as those who are driving at a comfortable speed."
According to Peterson, that doesn't mean that the State Police are also raising the speed limit "margin" that theoretically cushions all speed limits.
"Everyone thinks that if the speed limit is 70 mph, the police will allow you a cushion of an extra 15 mph before pulling you over for speeding," Peterson said.
"That's a misconception. Drivers shouldn't expect that when we raise the speed limit on the road that we also raise the limits pushed by the fastest drivers on the road."
The 55 mph limit goes back to the OPEC crisis of the 1970s when the federal government lowered the national speed limit to 55 mph.
"The mantra was '55 Saves Lives,' as well as fuel," Peterson said. "Eventually, most of our speed limits were later restored to 70 mph, but not all."
Freeways in southeastern Michigan where the limit will be hiked to 70 mph include: M-59 from Opdyke Road eastward; Interstate 75 from the southern Detroit city limits to Pennsylvania, at the Taylor city limit; and the M-53/Van Dyke freeway from M-59 north to 27 Mile Road.
"The Van Dyke freeway will be increased from 55 mph to 70 mph, but with limit reductions as you approach at grade intersections," Peterson. "Motorists will see speeds drop from 70 mph back to 55 mph for the last quarter mile of the freeway to the intersection."
Interstate 696 is currently under review by the MSP and MDOT, according to Peterson.
"I-696 is in the works, but raising the limit isn't imminent," he said.
"We will probably correct the speed limit for the entire length of I-696 after studies and reviews are evaluated and no latent problems are found. Freeways within the city of Detroit aren't on our list of studies."
I drove across Montana a few times under the Reasonable & Prudent rules an much prefer that to the posted 75 mph limit . In many of the wide open west 85 to 90 mph is the perfered and enforced speed limit regardless of what is posted .
In my last trip across the Montana there was a push to make drivers realize there was a daytime limit on radio & TV . " Woooo there Buddy there is a speed limit that is reasonable & prudent during the day " . It was playing on the weather radio at the rest area .
Traffic was flowing @ about 80 m ph in Wyoming on I-90 . When we crossed into Montana we all sped up to just under 90 mph . I drove 80 to 90 for around 9 + hours and felt no less safe than sitting on my couch .
All western states have a daytime enforced limit of 80 to 85 mph on rural interstates currently in the daytime & in good weather .
So these states should adopt the "Reasonable & Pudent" law on the books during daylight hours and 75 mph posted limit at night . That is after all what is enforced on any highway with a limit posted below the 85th percentile anyway in the US .
Any speed limit posted below the 85th percentile of traffic flow speed is a waste of time & money and doesn't make any road safer .
Make "Reasonable & Prudent" during the day and 75 mph limit at night the law on the books and save many of us the speeding fine in place currently in all 50 states .
In NC as in every other state with the widely posted 55 mph limit is a defalt speed for the enforced Reasonable & Prudent limits .
Anyone that drives on an unenforced unrealistly low limit posted highway is driving is a "Reasonable and Priudent" enforced road . In real world terms the road posted with unrealistictly low limit has no posted limit . We all must guess what the real limit is .
This makes no one safer .
Study Shows Speed Limit Differentials Compromise Highway Safety
Release Date: 3/21/2006
A new transportation study by University of Arkansas researchers reveals that different speed limits for cars and large trucks on rural, interstate highways lead to greater speed variation and a higher number of vehicles passing each other, thus compromising safety.
“We found that speed variation and vehicle interactions have a direct impact on highway safety,” said Steven Johnson, UA professor of industrial engineering with the Mack Blackwell National Rural Transportation Study Center. “Data from previous studies and simple logic say that a higher number of interactions among vehicles increases the chances that accidents will occur. Speed differentials -- 75 miles per hour for regular automobiles and 65 for large trucks, for example -- are a result of state-mandated speed limits and company policies that limit most trucks to a maximum speed of 62 to 65 miles per hour.”
Johnson reported this finding in “Cost-Benefit Evaluation of Heavy Truck-Automobile Speed Differentials on Rural Interstate Highways,” a comprehensive study of speed limits and car-vs.-large-truck speed differentials on rural, interstate highways. Sponsored by the U.S. Department of Transportation, commercial trucking companies and private fleets, the study will help regulatory agencies and trucking-company decision-makers establish policies regarding speed limits and differentials for both heavy trucks and automobiles.
After an extensive review and analysis of existing literature on speed limits, Johnson and Naveen Pawar, a graduate student in the College of Engineering, measured driver behavior -- in other words, speeds -- of heavy trucks and automobiles in five states with speed-limit configurations ranging from a uniform 75 mph for cars and heavy trucks to a low differential of 65 mph for automobiles and 55 mph for trucks. The researchers also collected and analyzed speed, accident and maintenance data and conducted hundreds of interviews with various stakeholders, including truck drivers; safety and maintenance managers of commercial trucking companies; and original equipment manufacturers of trucks, tires and engines.
There is a caveat, however, to the primary finding that differentials have a negative impact on safety: Johnson and Pawar agree with proponents of lower truck speed limits that vehicle dynamics, such as braking and maneuvering, improve on slower-moving trucks.
“People argue that heavy trucks require longer braking distances for any given speed, and lower truck speeds help equalize the stopping distance,” Johnson said. “On the other hand, opponents of lower truck speed limits have suggested that the differential speeds increase speed variance and therefore have a negative impact on highway safety. Our research demonstrates that it is likely that both of these arguments are correct.”
If transportation researchers, trucking-company safety personnel and motorists agree that highways are safer when vehicles travel at or close to a uniform speed, why do so many states have different speed limits for large trucks and cars? Furthermore, why is there so much speed-limit inconsistency from state to state? The argument that braking distances for slower-moving trucks is one reason and a perception of better fuel efficiency is another, but many factors unrelated to safety, road conditions and traffic influence decisions on setting speed limits.
“The large number of safety studies indicates that this issue has received a great amount of attention,” Johnson said. “Unfortunately, many of these studies involve more advocacy than science. It’s not that these studies aren’t valuable, but they have problems with methodology, statistical analysis and even simple understanding of important terms, such as ‘speeding.’ In accident data, speeding is defined as both ‘traveling faster than the posted limit’ and ‘traveling too fast for conditions.’ Studies often do not differentiate between these definitions.”
Johnson and Nawar reported these additional findings:
Speed-limit enforcement influences variation in traffic speeds. If speed limits are not strictly enforced, motorists choose their own “comfortable” speed.
Motorists tend to drive at speeds at which they are comfortable, regardless of posted speed limits. For example, speed data collected in the study illustrated that, although posted speed limits for automobiles differed by 10 mph, average speeds differed by only 1.6 mph. In other words, regardless of whether the speed limit was set at 65 mph or 75 mph, motorists drove between 73.2 and 74.8 mph.
If limits are set at what is considered to be arbitrarily low values, motorists will not adhere to those values. Johnson found significantly different compliance rates for the various speed-limit configurations. Compliance rates for the configuration of a uniform 70 mph were 31 percent for automobiles and 70 percent for trucks. By contrast, compliance rates for lower, posted differential limits -- 65 mph for cars, 55 mph for trucks -- were 7 percent for automobiles and 0 percent for trucks.
Despite many motorists’ perception that tractor-trailers pass them frequently, Johnson found that the average speed of trucks is 3 to 4 mph slower than the average speed of automobiles, even when speed limits were uniform.
Changes in posted speed limits affect speed variances. After a speed-limit change, there is a transition period and an adaptation period. During the transition period, some drivers adapt slowly to the higher limits while others immediately travel at or above the new limit. The behavioral difference of these two groups increases the amount of speed variance and results in a temporary but artificial indication of higher accident rates due to increased limits.
Commercial trucking company policies that restrict the maximum speed of their fleet by using speed limiters -- engine mechanisms that prevent trucks from traveling faster than a desired speed -- increase the amount of speed variance on interstate highways.
Driving time has a significant impact on truck-driver fatigue. However, up to the average traffic speed, higher speed does not result in additional fatigue.
Speed variance, in addition to vehicle speed, significantly affects fuel efficiency and the amount of pollution as both trucks and automobiles must accelerate and decelerate to maneuver around slower traffic.
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