Truck speed limits: a moderately hateful thread.

[Hobart]

On my trip to North Dakota last month, my dad and I noticed that there weren't any truck speed limits. For context, we live in Illinois, and the regular speed limit is 70 with trucks being stuck at 60 or 65. In North Dakota, trucks are allowed to drive 75.

My dad had an explanation, "It's because, unlike dumbass Illinois, they realize that it's good to have traffic moving at the same speed." Now, my dad isn't a huge fan of Illinois, but he does have a good point.

A car traveling five miles an hour under the speed limit is known to cause more accidents than a car going five above. What benefit is there to having a requirement for a quarter of vehicles on the road to go five or more under the speed limit?

[jeffandnicole]

On my trip to North Dakota last month, my dad and I noticed that there weren't any truck speed limits. For context, we live in Illinois, and the regular speed limit is 70 with trucks being stuck at 60 or 65. In North Dakota, trucks are allowed to drive 75.

My dad had an explanation, "It's because, unlike dumbass Illinois, they realize that it's good to have traffic moving at the same speed." Now, my dad isn't a huge fan of Illinois, but he does have a good point.

A car traveling five miles an hour under the speed limit is known to cause more accidents than a car going five above. What benefit is there to having a requirement for a quarter of vehicles on the road to go five or more under the speed limit?

There isn't, which is why most states have eliminated split speed limits.

[Scott5114]

A truck has greater mass and therefore, more kinetic energy than a car going the same speed [KE = (m × v²) ÷ 2]. Thus, if a truck gets in a wreck, the force exerted on whatever it hits will be greater, so it should be kept at a lower speed to likewise reduce the kinetic energy.

That's the theory, anyway. As your dad mentioned, keeping all vehicles around the same speed tends to reduce the number of wrecks, so the amount of force exerted by a truck crashing into something becomes irrelevant.

[bwana39]

On my trip to North Dakota last month, my dad and I noticed that there weren't any truck speed limits. For context, we live in Illinois, and the regular speed limit is 70 with trucks being stuck at 60 or 65. In North Dakota, trucks are allowed to drive 75.

My dad had an explanation, "It's because, unlike dumbass Illinois, they realize that it's good to have traffic moving at the same speed." Now, my dad isn't a huge fan of Illinois, but he does have a good point.

A car traveling five miles an hour under the speed limit is known to cause more accidents than a car going five above. What benefit is there to having a requirement for a quarter of vehicles on the road to go five or more under the speed limit?

As a GENERAL rule the tickets threshold is the same for both. By that I mean generally 8 to 10 mph above the higher of the two. What this actually means for trucks is a bigger ticket for the same speed as the car driver.

[Max Rockatansky]

It never seemed be a problem passing trucks at 75 MPH in Arizona or 80 MPH in Nevada.  The 55 MPH speed limit for trucks in California is largely universally ignored.

[Bruce]

States should prioritize enforcement of keeping trucks out of the left lane on freeways, since they create major safety hazards when trying to pass eachother. It's common in WA (thanks to trucks with BC plates, who I fear with every bone in my body).

[ran4sh]

Micropassing mostly exists because of insurance companies' influence on truck companies, which result in the trucks being governed to certain speeds which are similar but not exactly the same. The driver whose truck is slightly faster, tries to get past the slower truck because their pay often depends on it (e.g. if paid by mile).

So if a state wanted to prevent trucks from micropassing other trucks, they should prohibit the installation of those speed-governing devices on trucks.

[vdeane]

Micropassing mostly exists because of insurance companies' influence on truck companies, which result in the trucks being governed to certain speeds which are similar but not exactly the same. The driver whose truck is slightly faster, tries to get past the slower truck because their pay often depends on it (e.g. if paid by mile).

So if a state wanted to prevent trucks from micropassing other trucks, they should prohibit the installation of those speed-governing devices on trucks.

Meanwhile, wasn't there a proposed federal mandate at one point to require those governors be installed and set for 65 mph or below?

[machias]

The split speed limit on the Indiana Toll Road is one of the reasons I despise driving across Indiana.

[SkyPesos]

The split speed limit on the Indiana Toll Road is one of the reasons I despise driving across Indiana.

Indiana is no stranger to low speed limits in general...

[I-55]

The split speed limit on the Indiana Toll Road is one of the reasons I despise driving across Indiana.

Indiana is no stranger to low speed limits in general...

Try driving on any other road in the state without a split limit and you'll realize the split speed is the least of your concerns. May we someday move on from artificial 60 zones.