Differential speed limits

[Badger39]

After traveling from Madison WI to Lansing MI this Friday, I am more and more convinced that differential speed limits between cars and tricks are at best a pain in the *** and at worst downright dangerous.  Wisconsin has uniform speeds for all vehicles - and traffic moves along together.  Illinois and Michigan have slower truck speeds, and in Friday's heavy traffic I can't tell you the number of times all the cars were stuck driving behind two trucks passing each other at speeds below the auto speed limit. 

I'm sure stopping distances are longer for trucks moving 70 MPH and fuel expenses are lower, but it grew wearisome having to cut the cruise control to join a line of cars waiting to pass all the trucks.

Your thoughts?

[Hurricane Rex]

1. Illinois outlawed truck speed limits in rural areas a while ago, its just certain counties in suburban Chicago and St. Louis are 65T55. Now I'm not from that area and don't have a whole lot of experience with the suburban Chicago truck speed limits.

2. EVERY mile I've been on without cheating by plane has had a truck limit, because I've lived only in Oregon. I-5 has a default of 65T60 in Oregon, and 70T60 in Washington. Montana and California is worse with a 80T65 or 70T55. Its really annoying going 75 in Oregon and then having to slow down due to a truck. Back to cheating on the plane, I did not have to pass nearly as often there, or even in Idaho with 80T70/75T65 to a much lesser degree. Truck speed limits just make the road more dangerous.


Then again, 65 is a joke on I-5.

[JREwing78]

Michigan used to be a lot worse. For a number of years, cars were posted at 70 with trucks posted for 55. Your brakes got a workout, particularly when cars were typically running 10 over, and then suddenly having to scrub 25 mph in a flash when a truck cut you off. Now with trucks posted for 65 mph, it's not nearly as bad.

Don't mistake that for "good" - the 4-lane sections of I-94 in Michigan carry 7,500-15,000 commercial vehicles per day. *JUST* trucks! Add anywhere from 40,000-70,000 non-commercial vehicles on top of it, and you have yourself one busy road.

Now add lake-effect snow to the mix. There's a reason in winter I will frequently take an extra half-hour and use M-60 and US-12 to get across southern Michigan. I've had a few too many white-knuckle moments on I-94.

It's hard pulling good commercial vehicle numbers out of WisDOT, but I-39/90 south of Madison is being 6 and 8-laned to carry LESS traffic overall than I-94 in Michigan.

[oscar]

This issue has been discussed before, but more often using the term "split" rather than "differential" speed limits, in case you want to search for the older posts.

[Crash_It]

After traveling from Madison WI to Lansing MI this Friday, I am more and more convinced that differential speed limits between cars and tricks are at best a pain in the *** and at worst downright dangerous.  Wisconsin has uniform speeds for all vehicles - and traffic moves along together.  Illinois and Michigan have slower truck speeds, and in Friday's heavy traffic I can't tell you the number of times all the cars were stuck driving behind two trucks passing each other at speeds below the auto speed limit. 

I'm sure stopping distances are longer for trucks moving 70 MPH and fuel expenses are lower, but it grew wearisome having to cut the cruise control to join a line of cars waiting to pass all the trucks.

Your thoughts?

The issue is more of the trucks wanting to pass each other when the speed differential between them isn't sufficient enough to warrant a pass (for example one truck going 57 to pass the other that is going 56) than of the sheer existence of truck speed limits which usually are only in urban areas. At least here in IL. Also, every time I'm in WI on US41, there are trucks hogging 3, sometimes 4 of the 5 lanes slowly passing each other. GPS assisted speed limiters are the only solution to this problem.

[michravera]

After traveling from Madison WI to Lansing MI this Friday, I am more and more convinced that differential speed limits between cars and tricks are at best a pain in the *** and at worst downright dangerous.  Wisconsin has uniform speeds for all vehicles - and traffic moves along together.  Illinois and Michigan have slower truck speeds, and in Friday's heavy traffic I can't tell you the number of times all the cars were stuck driving behind two trucks passing each other at speeds below the auto speed limit. 

I'm sure stopping distances are longer for trucks moving 70 MPH and fuel expenses are lower, but it grew wearisome having to cut the cruise control to join a line of cars waiting to pass all the trucks.

Your thoughts?

The issue is more of the trucks wanting to pass each other when the speed differential between them isn't sufficient enough to warrant a pass (for example one truck going 57 to pass the other that is going 56) than of the sheer existence of truck speed limits which usually are only in urban areas. At least here in IL. Also, every time I'm in WI on US41, there are trucks hogging 3, sometimes 4 of the 5 lanes slowly passing each other. GPS assisted speed limiters are the only solution to this problem.

Citing trucks for impeding the normal and reasonable flow of traffic when they pass another truck in the only other lane of the road at less than the auto speed limit and actually do impede the normal and reasonable flow of traffic would be the fix. The trouble is much less in California on roads with 3 or more lanes in one direction since trucks aren't allowed out of the second-right lane EVER (unless there is no reasonable choice).

[Roadgeekteen]

I always wondered why California is so extreme in this regard.

[StogieGuy7]

Michigan used to be a lot worse. For a number of years, cars were posted at 70 with trucks posted for 55. Your brakes got a workout, particularly when cars were typically running 10 over, and then suddenly having to scrub 25 mph in a flash when a truck cut you off. Now with trucks posted for 65 mph, it's not nearly as bad.

Don't mistake that for "good" - the 4-lane sections of I-94 in Michigan carry 7,500-15,000 commercial vehicles per day. *JUST* trucks! Add anywhere from 40,000-70,000 non-commercial vehicles on top of it, and you have yourself one busy road.

Now add lake-effect snow to the mix. There's a reason in winter I will frequently take an extra half-hour and use M-60 and US-12 to get across southern Michigan. I've had a few too many white-knuckle moments on I-94.

It's hard pulling good commercial vehicle numbers out of WisDOT, but I-39/90 south of Madison is being 6 and 8-laned to carry LESS traffic overall than I-94 in Michigan.

I-94 across Michigan is inadequate at 4 lanes and the issue with truckers leaping into the left lane and going 65.2 mph to pass their buddy who's going 64.8 mph, thus jamming up traffic for several miles.  Multiply that by the thousands of trucks that use this route to connect Canada's 401 corridor with basically anywhere in the central or western USA and you've got an overburdoned freeway. 

Frankly, of all of the 4-lane roads I've seen, I-94 through Michigan is one of the more surprising.  It's the "main street" of Michigan, which is a state known to be very enthusiastic about travel by car.  How did this ever happen?

[kphoger]

The issue is more of the trucks wanting to pass each other when the speed differential between them isn't sufficient enough to warrant a pass (for example one truck going 57 to pass the other that is going 56) than of the sheer existence of truck speed limits which usually are only in urban areas. At least here in IL. Also, every time I'm in WI on US41, there are trucks hogging 3, sometimes 4 of the 5 lanes slowly passing each other. GPS assisted speed limiters are the only solution to this problem.

Speed limiters are likely the reason the truck isn't passing at 4 mph faster instead of 0.5 mph faster to begin with.

[Crash_It]

The issue is more of the trucks wanting to pass each other when the speed differential between them isn't sufficient enough to warrant a pass (for example one truck going 57 to pass the other that is going 56) than of the sheer existence of truck speed limits which usually are only in urban areas. At least here in IL. Also, every time I'm in WI on US41, there are trucks hogging 3, sometimes 4 of the 5 lanes slowly passing each other. GPS assisted speed limiters are the only solution to this problem.

Speed limiters are likely the reason the truck isn't passing at 4 mph faster instead of 0.5 mph faster to begin with.

That's why I said GPS assisted speed limiters. Meaning, the speed limiter will sense the given speed limit or truck speed limit and then limit the truck to that speed. This will stop that issue as well as the issue with truckers tailgating, speeding and other aggressive driving as commonly seen in Illinois and Indiana. Also, the trucker can also learn self control, courtesy and common sense and just not pass unless they can pass without holding up traffic.

[jakeroot]

I suppose it's rather specious to assume that one has to do with the other, but most European countries have truck limits while simultaneously having very safe roads. Good portions of Germany's Autobahn is obviously infamous for having no limit, but trucks over 3.85 US tons are limited to 50 mph. But then you have the UK, which now permits HGV's under 8.2 US-tons to travel at 70 with the rest of traffic (caravans and heavier HGV's are still limited to 60). I can't figure out which is best, especially since both the UK and Germany have remarkably good road safety records, though there's no clear connection with speed limits.

I've always been told that vehicles are safest when travelling at the same speed, but I guess trucks are just better off going slow, period? British Columbia has a maximum 120 km/h limit with no truck restrictions, but the BC Trucking Association and other groups like Jamie Davis Towing (who help with wrecks on the Coke) have historically opposed the higher limits, or sought variable limits like I-90 over Snoqualmie Pass (in WA).

It should be noted that modern trucks, especially those that are heavy, still take massively longer to stop compared to pretty much every car ever produced. That's sufficient reasoning, IMO, for lower truck limits, especially in areas with lots of curves or poor sight distance.

[kphoger]

The issue is more of the trucks wanting to pass each other when the speed differential between them isn't sufficient enough to warrant a pass (for example one truck going 57 to pass the other that is going 56) than of the sheer existence of truck speed limits which usually are only in urban areas. At least here in IL. Also, every time I'm in WI on US41, there are trucks hogging 3, sometimes 4 of the 5 lanes slowly passing each other. GPS assisted speed limiters are the only solution to this problem.

Speed limiters are likely the reason the truck isn't passing at 4 mph faster instead of 0.5 mph faster to begin with.

That's why I said GPS assisted speed limiters. Meaning, the speed limiter will sense the given speed limit or truck speed limit and then limit the truck to that speed. This will stop that issue as well as the issue with truckers tailgating, speeding and other aggressive driving as commonly seen in Illinois and Indiana. Also, the trucker can also learn self control, courtesy and common sense and just not pass unless they can pass without holding up traffic.

If the speed limit is 60 mph, that would not prevent a truck going 57 mph from passing another truck going 56 mph.  The other side of this coin is that, on a 65-mph highway, if there's a vehicle going 64 mph, then any truck wishing to pass would be limited to 65 mph, when the driver might otherwise pass at 67 mph.

FWIW, I think GPS-based speed limiting is a bad idea.  At my work, I've seen enough speeding alerts come in from our technicians' trucks to know it's far from foolproof.  Drive on a 65-mph expressway, cross over a side street with a 30-mph speed limit, and occasionally your truck's GPS will think you're driving 65 mph in a 30-mph zone.  Couple that with speed limiting, and it could be bad news.

[Crash_It]

The issue is more of the trucks wanting to pass each other when the speed differential between them isn't sufficient enough to warrant a pass (for example one truck going 57 to pass the other that is going 56) than of the sheer existence of truck speed limits which usually are only in urban areas. At least here in IL. Also, every time I'm in WI on US41, there are trucks hogging 3, sometimes 4 of the 5 lanes slowly passing each other. GPS assisted speed limiters are the only solution to this problem.

Speed limiters are likely the reason the truck isn't passing at 4 mph faster instead of 0.5 mph faster to begin with.

That's why I said GPS assisted speed limiters. Meaning, the speed limiter will sense the given speed limit or truck speed limit and then limit the truck to that speed. This will stop that issue as well as the issue with truckers tailgating, speeding and other aggressive driving as commonly seen in Illinois and Indiana. Also, the trucker can also learn self control, courtesy and common sense and just not pass unless they can pass without holding up traffic.

If the speed limit is 60 mph, that would not prevent a truck going 57 mph from passing another truck going 56 mph.  The other side of this coin is that, on a 65-mph highway, if there's a vehicle going 64 mph, then any truck wishing to pass would be limited to 65 mph, when the driver might otherwise pass at 67 mph.

FWIW, I think GPS-based speed limiting is a bad idea.  At my work, I've seen enough speeding alerts come in from our technicians' trucks to know it's far from foolproof.  Drive on a 65-mph expressway, cross over a side street with a 30-mph speed limit, and occasionally your truck's GPS will think you're driving 65 mph in a 30-mph zone.  Couple that with speed limiting, and it could be bad news.

It would be modernized to know that isn't the case. I wouldn't have a problem with being behind a truck going 65/65 to pass one that is going 64. I usually drive the speed limit anyway and a truck should not ever go over the speed limit. That's why there are so many rollover crashes.

[michravera]

The issue is more of the trucks wanting to pass each other when the speed differential between them isn't sufficient enough to warrant a pass (for example one truck going 57 to pass the other that is going 56) than of the sheer existence of truck speed limits which usually are only in urban areas. At least here in IL. Also, every time I'm in WI on US41, there are trucks hogging 3, sometimes 4 of the 5 lanes slowly passing each other. GPS assisted speed limiters are the only solution to this problem.

Speed limiters are likely the reason the truck isn't passing at 4 mph faster instead of 0.5 mph faster to begin with.

That's why I said GPS assisted speed limiters. Meaning, the speed limiter will sense the given speed limit or truck speed limit and then limit the truck to that speed. This will stop that issue as well as the issue with truckers tailgating, speeding and other aggressive driving as commonly seen in Illinois and Indiana. Also, the trucker can also learn self control, courtesy and common sense and just not pass unless they can pass without holding up traffic.

We'd be a lot better off, if professional drivers would just always act professionally. It takes quite a while for a truck with a load to move over, even longer to accelerate to a decent passing speed, a long time to pass another long vehicle, and a long time to get back over in safety. Professional drivers should be able to make this calculation professionally and give due regard for the amount of clear space in the next lane behind them. If they can't do what they need to do in safety and without impeding the normal and reasonable flow of traffic, they shouldn't initiate the passing move. There are sections of I-5 between I-580 and the CASR-99 junction where it is possible that trucks should just flat out be prohibited from passing from 5AM to 7PM. I would hope that we wouldn't have to impose that restriction. I would hope that we would add a third lane and that we could all just get along!

[Crash_It]

The issue is more of the trucks wanting to pass each other when the speed differential between them isn't sufficient enough to warrant a pass (for example one truck going 57 to pass the other that is going 56) than of the sheer existence of truck speed limits which usually are only in urban areas. At least here in IL. Also, every time I'm in WI on US41, there are trucks hogging 3, sometimes 4 of the 5 lanes slowly passing each other. GPS assisted speed limiters are the only solution to this problem.

Speed limiters are likely the reason the truck isn't passing at 4 mph faster instead of 0.5 mph faster to begin with.

That's why I said GPS assisted speed limiters. Meaning, the speed limiter will sense the given speed limit or truck speed limit and then limit the truck to that speed. This will stop that issue as well as the issue with truckers tailgating, speeding and other aggressive driving as commonly seen in Illinois and Indiana. Also, the trucker can also learn self control, courtesy and common sense and just not pass unless they can pass without holding up traffic.

We'd be a lot better off, if professional drivers would just always act professionally. It takes quite a while for a truck with a load to move over, even longer to accelerate to a decent passing speed, a long time to pass another long vehicle, and a long time to get back over in safety. Professional drivers should be able to make this calculation professionally and give due regard for the amount of clear space in the next lane behind them. If they can't do what they need to do in safety and without impeding the normal and reasonable flow of traffic, they shouldn't initiate the passing move. There are sections of I-5 between I-580 and the CASR-99 junction where it is possible that trucks should just flat out be prohibited from passing from 5AM to 7PM. I would hope that we wouldn't have to impose that restriction. I would hope that we would add a third lane and that we could all just get along!

Then you'll have the 2 right lanes backed up by trucks riding next to each other. See it in IL all the time and as a result, you'll get an even more rogue trucker coming into the restricted lane to pass. I have it so many times on my dashcam that I just stopped locking the clip.

[kphoger]

If they can't do what they need to do in safety and without impeding the normal and reasonable flow of traffic, they shouldn't initiate the passing move.

That's only reasonable in flat terrain.  It can and does happen that, when a trucker starts to overtake a slower vehicle, it appears easy enough to complete the maneuver–but, a mile down the road or so, there begins a slight uphill which he cannot overcome at the same speed, and so his speed drops to match that of the slower vehicle or even less.  That wasn't being unprofessional, it just happens.



↓  This is the way the conversation should have gone.  ↓

the speed limiter will sense the given speed limit or truck speed limit and then limit the truck to that speed

on a 65-mph highway, if there's a vehicle going 64 mph, then any truck wishing to pass would be limited to 65 mph, when the driver might otherwise pass at 67 mph.

Then you'll have the 2 right lanes backed up by trucks riding next to each other.

[michravera]

If they can't do what they need to do in safety and without impeding the normal and reasonable flow of traffic, they shouldn't initiate the passing move.

That's only reasonable in flat terrain.  It can and does happen that, when a trucker starts to overtake a slower vehicle, it appears easy enough to complete the maneuver—but, a mile down the road or so, there begins a slight uphill which he cannot overcome at the same speed, and so his speed drops to match that of the slower vehicle or even less.  That wasn't being unprofessional, it just happens.



↓  This is the way the conversation should have gone.  ↓

the speed limiter will sense the given speed limit or truck speed limit and then limit the truck to that speed

on a 65-mph highway, if there's a vehicle going 64 mph, then any truck wishing to pass would be limited to 65 mph, when the driver might otherwise pass at 67 mph.

Then you'll have the 2 right lanes backed up by trucks riding next to each other.

I say, up to a point, let trucks pass as they are able at whatever speed of which the truck is capable or to which it is limited, but not by impeding the normal and reasonable flow of traffic in a lane in which they are only authorized to be in order to pass. With only 3 lanes in one direction, California only allows trucks in the middle lane to for passing. So, driving at a speed that is well below the car speed limit in order to pass isn't and shouldn't be allowed. On the other hand, even if they bottled up the right two lanes, there's still the left available in that scenario.

Also, I disagree that a professional shouldn't take into account and be aware of the terrain ahead. If a hill (or even a rise) will keep them from passing without impeding the normal and reasonable flow of traffic, they should not attempt the move. Professional should know the capabilities of their equipment.

[kphoger]

Also, I disagree that a professional shouldn't take into account and be aware of the terrain ahead. If a hill (or even a rise) will keep them from passing without impeding the normal and reasonable flow of traffic, they should not attempt the move. Professional should know the capabilities of their equipment.

So you think truck drivers should survey a detailed topographical map of their entire route and commit it to memory, such that they know exactly where every rise in the road is and what the gradient is for each?  Or do you think they should be required to have X-ray vision so they can see a rise in the road through the traffic in front of them?

Sorry, bud, but I used to drive a box truck for a living.  Even on roads I knew like the back of my hand in my usual territory, I couldn't keep track of exactly what speed I could maintain for every rise in every road–much less on roads I was less familiar with.  It's simply not a reasonable or achievable goal to expect drivers to predict the road like that.

[kphoger]

I say, up to a point, let trucks pass as they are able at whatever speed the truck of which the truck is capable or to which it is limited, but not by impeding the normal and reasonable flow of traffic in a lane in which they are only authorized to be in order to pass.

So can I assume, then, that you're no longer in favor of GPS-based speed limiters?

[jeffandnicole]

Also, I disagree that a professional shouldn't take into account and be aware of the terrain ahead. If a hill (or even a rise) will keep them from passing without impeding the normal and reasonable flow of traffic, they should not attempt the move. Professional should know the capabilities of their equipment.

So you think truck drivers should survey a detailed topographical map of their entire route and commit it to memory, such that they know exactly where every rise in the road is and what the gradient is for each?  Or do you think they should be required to have X-ray vision so they can see a rise in the road through the traffic in front of them?

Sorry, bud, but I used to drive a box truck for a living.  Even on roads I knew like the back of my hand in my usual territory, I couldn't keep track of exactly what speed I could maintain for every rise in every road—much less on roads I was less familiar with.  It's simply not a reasonable or achievable goal to expect drivers to predict the road like that.

So then did you slow up and merge back over behind the vehicle you were trying to pass, or did you give everyone else the big FU and blocked traffic until you were able to gain a little speed?

[kphoger]

So then did you slow up and merge back over behind the vehicle you were trying to pass, or did you give everyone else the big FU and blocked traffic until you were able to gain a little speed?

I would slow down and get back over into the right lane.  However, I don't think I've ever seen a big rig driver do that in a similar situation.  Maybe once...

[michravera]

I say, up to a point, let trucks pass as they are able at whatever speed the truck of which the truck is capable or to which it is limited, but not by impeding the normal and reasonable flow of traffic in a lane in which they are only authorized to be in order to pass.

So can I assume, then, that you're no longer in favor of GPS-based speed limiters?

I never said that I was in favor of such limiting devices. I can see a company policy limiting the truck to like 68 MPH or something like that. To my way of thinking, if they aren't capable of going 70 MPH (because of company limitation). they shouldn't be in the lane for 70 MPH traffic unless the two trucks involved basically have the road to themselves. I also haven't taken a position on the increase to 65MPH on the truck speed limit in California (on rural roads, presumably where cars can go 70 MPH).

[kphoger]

I never said that I was in favor of such limiting devices.

Sorry, I got your replies and Crash_It's replies mixed up.

I can see a company policy limiting the truck to like 68 MPH or something like that. To my way of thinking, if they aren't capable of going 70 MPH (because of company limitation). they shouldn't be in the lane for 70 MPH traffic unless the two trucks involved basically have the road to themselves. I also haven't taken a position on the increase to 65MPH on the truck speed limit in California (on rural roads, presumably where cars can go 70 MPH).

(1)  You seem to consider the speed limit to be a minimum rather than a maximum.  If your vehicle can't go over 70 mph, then there's no reason you shouldn't be allowed in a lane where all traffic is required by law to drive under 70 mph.

(2)  Where you live, are there lanes with different speed limits side-by-side?  I've seen that before, but never in the USA.  My opinion of it can be found here.  If, on the other hand, all lanes have the same speed limit, then there's no such thing as "the lane for 70 MPH traffic".  It's just as illegal to drive 71 mph in the left lane as in the right lane, and it's just as legal to drive 69 mph in the left lane as in the right lane.

(3)  Speed limits and keep-right laws operate side-by-side in order to produce good driving behavior.  They are related, but they are not the same thing, nor are they mutually exclusive.  Driving 90 mph doesn't mean you somehow have the right to block the left lane to anyone driving 95 mph, and driving 65 mph doesn't mean you're never allowed into the left lane.  I'm a huge proponent of keeping right except to pass, but "slower traffic" is a relative term, not an absolute one.

[michravera]

I never said that I was in favor of such limiting devices.

Sorry, I got your replies and Crash_It's replies mixed up.

I can see a company policy limiting the truck to like 68 MPH or something like that. To my way of thinking, if they aren't capable of going 70 MPH (because of company limitation). they shouldn't be in the lane for 70 MPH traffic unless the two trucks involved basically have the road to themselves. I also haven't taken a position on the increase to 65MPH on the truck speed limit in California (on rural roads, presumably where cars can go 70 MPH).

(1)  You seem to consider the speed limit to be a minimum rather than a maximum.  If your vehicle can't go over 70 mph, then there's no reason you shouldn't be allowed in a lane where all traffic is required by law to drive under 70 mph.

(2)  Where you live, are there lanes with different speed limits side-by-side?  I've seen that before, but never in the USA.  My opinion of it can be found here.  If, on the other hand, all lanes have the same speed limit, then there's no such thing as "the lane for 70 MPH traffic".  It's just as illegal to drive 71 mph in the left lane as in the right lane, and it's just as legal to drive 69 mph in the left lane as in the right lane.

(3)  Speed limits and keep-right laws operate side-by-side in order to produce good driving behavior.  They are related, but they are not the same thing, nor are they mutually exclusive.  Driving 90 mph doesn't mean you somehow have the right to block the left lane to anyone driving 95 mph, and driving 65 mph doesn't mean you're never allowed into the left lane.  I'm a huge proponent of keeping right except to pass, but "slower traffic" is a relative term, not an absolute one.

As re #1: Agreed, but 63 MPH in the left lane where traffic is allowed to go 70 MPH will often impede the normal and reasonable flow of traffic and that isn't allowed under California Law.

As re #2: There are several places on I-80 in California in the Sierras where the right lane has a 50 MPH speed limit and the rest of the road is posted at 65 MPH. In California, trucks are only allowed out of the right lane in order to pass and then only in the second right lane. With 4 or more lanes in the same direction, they are allowed only in the right two lanes (unless there is a permissive sign or there is some reason why the must be there, like a left exit or left turn, the right two lanes are exit only, etc). On I-5 (which I think that we can both agree needs a third lane that would fix about 97% of our problems and could be built in the existing right of way), it is too frequent of an occurrence that trucks going 63 or 64 MPH (for which they could currently be ticketed for exceeding the State Maximum 55 MPH for trucks) will block the normal and reasonable flow of traffic for quite a while. Perhaps, if we let trucks go 65 MPH in these places, they either wouldn't feel the need to pass as often or would be passing at a higher speed that would get the move completed in a shorter time. On the other hand, 30-40 tons is a lot of weight to be throwing around at 65 MPH (or faster).

As re #3: I think that I tried to explain approximately the same thing in approximately the same way to an "Over the Posted Limit is always wrong" dingbat in the old m.t.r newsgroup. So, I think that, if you want an argument, we need a different subject than this one.

[NoGoodNamesAvailable]

I never said that I was in favor of such limiting devices.

Sorry, I got your replies and Crash_It's replies mixed up.

I can see a company policy limiting the truck to like 68 MPH or something like that. To my way of thinking, if they aren't capable of going 70 MPH (because of company limitation). they shouldn't be in the lane for 70 MPH traffic unless the two trucks involved basically have the road to themselves. I also haven't taken a position on the increase to 65MPH on the truck speed limit in California (on rural roads, presumably where cars can go 70 MPH).

(1)  You seem to consider the speed limit to be a minimum rather than a maximum.  If your vehicle can't go over 70 mph, then there's no reason you shouldn't be allowed in a lane where all traffic is required by law to drive under 70 mph.

(2)  Where you live, are there lanes with different speed limits side-by-side?  I've seen that before, but never in the USA.  My opinion of it can be found here.  If, on the other hand, all lanes have the same speed limit, then there's no such thing as "the lane for 70 MPH traffic".  It's just as illegal to drive 71 mph in the left lane as in the right lane, and it's just as legal to drive 69 mph in the left lane as in the right lane.

(3)  Speed limits and keep-right laws operate side-by-side in order to produce good driving behavior.  They are related, but they are not the same thing, nor are they mutually exclusive.  Driving 90 mph doesn't mean you somehow have the right to block the left lane to anyone driving 95 mph, and driving 65 mph doesn't mean you're never allowed into the left lane.  I'm a huge proponent of keeping right except to pass, but "slower traffic" is a relative term, not an absolute one.

Thank you! The American idea of lane discipline ("fast lane," "slow lane") is completely screwed. Your lane selection, maybe with the exception of climbing lanes, should have nothing to do with your absolute speed. It has to do with your speed relative to the traffic immediately around you, i.e. whether you're passing. People think it's their god-given right to go 85 mph in the passing lane and tailgate you even when you're going a good 10 mph faster than traffic in the right lane.

On the other end, you have the "What buddy, I'm not going fast enough for ya?" crowd, who feel whatever speed they're going is the only correct one and decide to enforce it on everyone in the left lane behind them. These people also tend to complain about people passing them on the right (or even better, "passing me on the right even when I'm speeding!"), which:

a, shouldn't be an issue if you're aware of your surroundings;

b, isn't illegal, and;

c, should hardly ever happen if you keep proper lane discipline.