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http://www.cleanmpg.com/photos/data/2/AmericanFlag.jpg Car and truck speed limits will be the same in Illinois. (http://www.pantagraph.com/news/local/article_c6696e48-8919-11de-ac4d-001cc4c002e0.html)

http://www.cleanmpg.com/photos/data/523/Driving_SMART_next_to_a_dual_trailered_semi_Medium.jpgKurt Erickson - PANTAGRAPH (http://www.pantagraph.com) - August 14, 2009

The new Governor of Illinois obviously has no regard for fuel consumption or safety. --Ed.

Illinois could soon join most other states in having a uniform speed limit for cars and trucks on its highways.

Gov. Pat Quinn is expected to formally endorse legislation that boosts the speed limit for semitrailer trucks to 65 miles per hour on rural interstates, the bill's Senate sponsor said Friday.

Currently, the legal limit for big rigs is set at 55 mph. Supporters of the change say it is ... http://www.pantagraph.com/news/local/article_c6696e48-8919-11de-ac4d-001cc4c002e0.html

I've heard time and again here that the trucker/police ignore it anyway. Where is the evidence that it is more dangerous for trucks to have the same speed limit as cars?

Where is the evidence that it is more dangerous for trucks to have the same speed limit as cars?

A semi truck has more kinetic energy than a car at the same speed.

I've heard time and again here that the trucker/police ignore it anyway. Where is the evidence that it is more dangerous for trucks to have the same speed limit as cars?

FWIW they don't totally ignore it in West and Central Illinois--most trucks tend to run 60ish while the cars tend to run 70ish. There are speed outliers that run faster and slower in both groups. The new limits will probably put most trucks up into the 65-70 range on the open road.

I would guess that unifying the speed limit at the current truck speed limit would be a safer, but pretty unpopular change.

A few close encounters with wildlife have convinced me that 65 is an unsafe nighttime speed in rural areas.

2 words: Wrong direction.

While I'm all for sticking it to 18wheelers (I was hit by one a few years ago), I don't see a good reason for making them drive slower. The only valid reason would be that they have longer stopping distances. Otherwise, they contain trained drivers whereas cars contain drivers of varying skill levels.

Maybe I should explain my comment better. I was intending to relay my opinion that the speed limit should be lowered to 55 for cars and trucks.

While I'm all for sticking it to 18wheelers (I was hit by one a few years ago), I don't see a good reason for making them drive slower. The only valid reason would be that they have longer stopping distances. Otherwise, they contain trained drivers whereas cars contain drivers of varying skill levels.


from what i have seen on I94 during my recent bout of long distance commuting, not all "trained" drivers demonstrate any more skill than the rest of the morons on the road. i have seen them tailgating, doing unsafe lane changes, speeding, and all the other dangerous techniques used in cars.

Reminds me of the bikers that tried to tell me they were more alert on the road than hypermilers...If I could list the amount of driving and riding infractions the younger fellow had, there wouldn't be enough space on cleanmpg to contain the mess.

A semi truck has more kinetic energy than a car at the same speed.

That's not evidence that it is better to have trucks driving 10 mph slower around faster moving cars.

That's not evidence that it is better to have trucks driving 10 mph slower around faster moving cars.

I fail to see any common sense in this statement. A heavier object, moving at the same speed, will do more damage to a smaller object with less mass. I've been to enough FSV vs compact, or semi vs. car or FSP collisions to attest to this.

Granted, you are partially correct that the damage, and danger, will vary based on the vehicles colliding. An unloaded semi vs. a super duty puckup or International DT 4300, for example will fair batter overall than a loaded 60,000 lb semi and a Smart car.

TO suggest that semis moving at high speed pose no greater risk to other drivers, most of whom are hopelessly outweighed in gross tonnage by a semi, is oblivious to reality at best.
For an extreme example, look at what a train, even a small and relatively "light" commuter train, will do to a car or a semi.

Here is a tractor trailer safety report (http://www.truckinjuries.com/trucking_accidents_facts.html) with interesting stats.

I fail to see any common sense in this statement. A heavier object, moving at the same speed, will do more damage to a smaller object with less mass. I've been to enough FSV vs compact, or semi vs. car or FSP collisions to attest to this.

Granted, you are partially correct that the damage, and danger, will vary based on the vehicles colliding. An unloaded semi vs. a super duty puckup or International DT 4300, for example will fair batter overall than a loaded 60,000 lb semi and a Smart car.

TO suggest that semis moving at high speed pose no greater risk to other drivers, most of whom are hopelessly outweighed in gross tonnage by a semi, is oblivious to reality at best.
For an extreme example, look at what a train, even a small and relatively "light" commuter train, will do to a car or a semi.

All true but you ignore the issue that there are also accidents caused by deviations from average speed, and mutliple speed limits have deviations designed in.

Everything is a compromise with trade-offs, I haven't seen any good evidence that 65 car and 55 truck is better than 65 for all. Most states don't feel there is a worthwhile benefit.

Talk of common sense is subjective. Common sense tells me less speed deviation equals less accidents.

All true but you ignore the issue that there are also accidents caused by deviations from average speed, and mutliple speed limits have deviations designed in.

Everything is a compromise with trade-offs, I haven't seen any good evidence that 65 car and 55 truck is better than 65 for all. Most states don't feel there is a worthwhile benefit.

Talk of common sense is subjective. Common sense tells me less speed deviation equals less accidents.

Of course, one could also be a devil's advocate and use this double edged sword against hypermiling despite no proof of a public hazard. I agree that large deviations in an average speed cause accidents, such as when I try to at least stay close to 45 mph construction zone psls. A 10 mph deviation does allow for differences in braking distances, etc. Larger deviations would increase the risk of collisions, correct?

Traveling interstates in Illinois, I follow very few tractor trailers. Driving 55 mph on a 55 mph highway gets me passed by semis going 65 to 70. Driving 60 to 65mph on interstates, I am still passed by semis going 70,75, or 80.

Note the crumpled metal between the trucks.
http://www.cleanmpg.com/photos/data/591/car_versus_truck_640.JPG

I listen to the truckers channel on Sirius quite a bit. They feel that the diffenent speed limits are dangerous due to the constant passing that it creates. That is also the main complain detractors have about the driving style of some of us. The truckers also say that their trucks are designed for a very narrow range of speed and slowing down causes them to have to use a lower gear.

Maybe I should explain my comment better. I was intending to relay my opinion that the speed limit should be lowered to 55 for cars and trucks.

My thoughts exactly!

it is actually safer for all vehicles to be travelling at the same speed.

Look at this chart for Braking Distance (http://www.batesville.k12.in.us/physics/PhyNet/Mechanics/Kinematics/BrakingDistData.html)s to see the differences in stopping distances.


Here is another link of interest (http://www.associatedcontent.com/article/762159/safe_driving_tips_around_tractor_trailers.html?cat=27) also.

Uniform speed limits causes more trucks to be passing. I hope I don't have to explain why a truck passing a car is more dangerous than a car passing a truck. With these obese transportation devices on the same roads, it is better to keep them at a limit where the car is in "control". Less time is spent passing a truck and trucks spend less time passing.

I agree that uniform speeds are safer....which is why I like the lower speed limit for trucks. Trucks, like most traffic, seem to travel about 10+mph over the limit, so having them at 55+10, made them fairly safe if I was going the 65 limit.

When I'm in the 65mph or 70mph speed limits for all vehicles, I have semis flying past me quite regularly even if I do 65/70. Many, like car drivers, wait till the last moment. Frankly there have been far too many times, where they popped left with such little time left, that had a car gotten there first and blocked them, they would have had to smack that car or me. Too many truck drivers are professionals in the same way as illegal prostitutes...they do it for money, and don't give a damn about any body elses safety.

Appologies to the pro drivers with us that do play it safe. You may not be the exception, but on any given interstate trip, it sure feels like it.

Very well put. I would like to see the differences in fuel consumption from 55 to 65 mph.


I agree that uniform speeds are safer....which is why I like the lower speed limit for trucks. Trucks, like most traffic, seem to travel about 10+mph over the limit, so having them at 55+10, made them fairly safe if I was going the 65 limit.

When I'm in the 65mph or 70mph speed limits for all vehicles, I have semis flying past me quite regularly even if I do 65/70. Many, like car drivers, wait till the last moment. Frankly there have been far too many times, where they popped left with such little time left, that had a car gotten there first and blocked them, they would have had to smack that car or me. Too many truck drivers are professionals in the same way as illegal prostitutes...they do it for money, and don't give a damn about any body elses safety.

Appologies to the pro drivers with us that do play it safe. You may not be the exception, but on any given interstate trip, it sure feels like it.

Here is a tractor trailer safety report (http://www.truckinjuries.com/trucking_accidents_facts.html) with interesting stats.

From the link: " The Insurance Institute for Highway Safety reports that in crashes involving large trucks and other vehicles, 98% of the fatalities occur to the people in passenger vehicles."

Some time ago, I picked up a figure that in fatal car-truck crashes, the car is at fault 75% of the time, but the car occupants account for 96% of the fatalities. The link above indicates the fatality ratio is even worse.

Drivers of both should be held to higher standards, but the greater lethality of trucks means their standard needs to be significantly higher.

... Note the crumpled metal between the trucks. ...

Cars are getting stronger. The two trucks are not in contact, unlike the picture of a fiery local crash remnant a decade ago that is seared into my memory. Another hundred years of crash safety improvements, and we'll start seeing some survivors in the car. :mad:.

My state has a 60-Truck / 70-Car limit on rural Interstates. We have few trucks here, but plenty of 18- to 26-wheel cars.