New Tax on hybrid cars

[Seasoned Oak]

Quote
The need for road surface maintenance is greatly attributable to the heaviest vehicles. Based on the findings of the American Association of State Highway Officials (AASHO) road test, damage caused by heavy trucks was long thought to increase with approximately the fourth power of the axle load. This means that one axle of 10 tons on a heavy truck was 160,000 times more damaging to a road surface than an axle of 0.5 tons (car scale).End quote

160,000 times more damaging to the road tha a car ! I rest my case.

 

[EatenByLimestone]

On the way back I saw a tanker filling up the tanks of a gas station. I actually thought of pulling over and asking to measure tires. :D

I bet that the load isn't carried equal in most 18 wheeler trailers. With the rear tires so far back there has to be a lot of tongue weight. Gasoline tankers also appear to carry more than one grade of fuel so they must be partitioned for it. I imagine they carry more 87 than 89 or 92/93 also. I was hoping there was some guy on the board who drove them.

Maybe there is a civil engineer on the board who could enlighten us about different types of road damage? Since you see different road ratings for sections of road there has to be differences in foundations, but assuming the road isn't abused by a vehicle too heavy for it, how does it wear?

Matt

 

[EatenByLimestone]

Quote
The need for road surface maintenance is greatly attributable to the heaviest vehicles. Based on the findings of the American Association of State Highway Officials (AASHO) road test, damage caused by heavy trucks was long thought to increase with approximately the fourth power of the axle load. This means that one axle of 10 tons on a heavy truck was 160,000 times more damaging to a road surface than an axle of 0.5 tons (car scale).End quote

160,000 times more damaging to the road tha a car ! I rest my case.

Before you rest your case maybe you can explain it in more detail.

Thank you beforehand.

Matt

 

[semipro]

On the way back I saw a tanker filling up the tanks of a gas station. I actually thought of pulling over and asking to measure tires. :D

I bet that the load isn't carried equal in most 18 wheeler trailers. With the rear tires so far back there has to be a lot of tongue weight. Gasoline tankers also appear to carry more than one grade of fuel so they must be partitioned for it. I imagine they carry more 87 than 89 or 92/93 also. I was hoping there was some guy on the board who drove them.Matt

Interesting related item. I was once told that tankers carried only the low and high grades in the tankers with two respective tanks at gas stations. The mid-grade fuel is made at the pump by mixing the low and high grades.

 

[Seasoned Oak]

Before you rest your case maybe you can explain it in more detail.
Thank you beforehand.
Matt

You would have to ask these people to explain their test. Im just quoting the article.
American Association of State Highway Officials (AASHO) road test.

 

[Frozen Canuck]

Having a hard time with a big rig putting the same psi down on a road as a vehicle myself. For most of the year we drive the oil leases with 4x4 pickups, mud flying everywhere mind you. A triple axle tractor with a triple axle trailer tries the same road and down to the axles/frame she goes & out come the D8's to pull her out. Just can't see how those two vehicles are putting down anywhere near close to the same psi on the road.

 

[jharkin]

I'm not convinced that large trucks automatically do more damage. It would seem to me that the damage would related to the weight spread out on the individual contact patches of the tire. The size and amount of the contact patches would determine the damage. The small car may weigh much less, but have fewer square inches of tire touching the pavement to spread the weight out. A larger vehicle may have more square inches of tire touching the ground therefore any square inch may have fewer pounds of pressure on it. A Prius weighs much less than a dually, but the dually has larger tires and 6 of them to help distribute the weight.

Does anybody care to make measurements of the contact patches of a dually and a Prius to test this? Does anybody drive a Peterbuilt that we can measure the contact patches just for giggles?

LIme and Semipro-

I think you have your math worng..

Regardless of the actual size of the tire, contact patch roughly equals the load on the tire divided by the inflation pressure in PSI. This is why offroaders deflate their tires to drive on sand - it increase the contact patch.


So if you have a 3000 lb Prius, and its tires are inflated to 30psi, there is 100 in2 of contact patch devided over 4 tires, each doing pressing down with a force of 30 lb (see the psi).


Then you have your loaded 80,000lb 18 wheeler which runs 80+psi in its tires. 80,000/80 = 1,000 in2 of contact patch each applying 80 lb of force on the road.

Not even a contest...

 

[jharkin]

I bet that the load isn't carried equal in most 18 wheeler trailers. With the rear tires so far back there has to be a lot of tongue weight. Gasoline tankers also appear to carry more than one grade of fuel so they must be partitioned for it. I imagine they carry more 87 than 89 or 92/93 also. I was hoping there was some guy on the board who drove them.

The difference in weight between a gallon of 87 and a gallon of 93 is negligible - only a couple of ounces. 89 is made at the pump by mixing the other 2 grades.

You are right the weight per axle is different. There are different limits for the steering and drive axles. The steering axles carry the least, the axles at the back of the trailer more, and the drive axles at the tongue carry the most, as they are taking a lot of the trailer weight and a lot of the cab/driveline weight (this is good for drive traction).

Take a look at a typical layout:

notice the overhang at the back? This puts slightly more of the trailer weight (assuming its equally loaded) over the rear trailer axles, to partially offset the extra cab weight at the drive axles.

Maybe there is a civil engineer on the board who could enlighten us about different types of road damage? Since you see different road ratings for sections of road there has to be differences in foundations, but assuming the road isn't abused by a vehicle too heavy for it, how does it wear?

No matter how light the vehicle, every time a loaded tire passes along a road its applying and releasing a force on the road surface which causes the pavement to flex very slightly. Even if each flex is extremely small, over time the cumulative effects of all those flexing events (fatigue) builds up until cracks, etc form.

 

[semipro]

I think you have your math worng.. Regardless of the actual size of the tire, contact patch roughly equals the load on the tire divided by the inflation pressure in PSI. This is why offroaders deflate their tir

So you're saying if the tire pressure is halved the contact patch doubles?
I agree that lower pressure results in more contact area but doubt the relationship is linear.
The structure of the tire itself also acts to support the load.

Edit: Found this:
From:http://en.wikipedia.org/wiki/Contact_patch
Statically, the size, shape, and pressure distribution are functions of many things,the most important of which are the load on the tire and the inflation pressure:

• The larger the load on the tire, the larger the contact patch.
• The larger the inflation pressure, the smaller the contact patch.

Unfortunately, these two properties are not linearly proportional to the area of the contact. Put another way, a 10% change in load or inflation pressure usually does not result in a 10% change in the contact patch.[2] This makes intuitive sense, because while the load or pressure of a tire can be altered freely, the contact patch size will always be limited by the tire geometry.

Tire pressure really has nothing to do with our original discussion though, or very little. The weight of the truck divided by the contact area yields loading in force per unit area....period. As mentioned earlier some tires likely are loaded more than others though.

 

[jharkin]

You are right Semipro that it is not a linear relationship. If tires where just squishy innertubes it would be but in the real world sidewall stiffness, etc plays a role. BUt still, There is no doubt a semi is doing more damage. Even if you could mathematically prove one Prius tire causes damage than 1 semi tire (which I highly doubt but am open to being proved wrong), the semi is still giving the road 18 poundings to the Prius' 4.

 

[Jags]

I spent a little time looking around and came across at least one credible reference indicating that attribution of road damage is more complex than that. Check out http://www.fhwa.dot.gov/policy/091116/03.htm

Take a piece of cling wrap from your cupboard. Stretch tight. Apply a single pound in the center square inch. Now apply 10 pounds over the center 10 square inches. Not the same thing.

 

[semipro]

Even if you could mathematically prove one Prius tire causes damage than 1 semi tire (which I highly doubt but am open to being proved wrong), the semi is still giving the road 18 poundings to the Prius' 4.

Actually, I showed above (post 25) that one semi tire does create more load-per-unit-area than does a Prius so we're in agreement.

 

[semipro]

Take a piece of cling wrap from your cupboard. Stretch tight. Apply a single pound in the center square inch. Now apply 10 pounds over the center 10 square inches. Not the same thing.

Agreed but I'm not sure your point.

 

[Jags]

Agreed but I'm not sure your point.

That using a base line of pounds per square inch isn't the only factor. Total pounds can have a much more damaging effect. 10 pounds on that cling wrap would have caused catastrophic failure.

 

[semipro]

See my posts 16, 25, 34.
I'm not sure where we're in disagreement.

 

[Jags]

See my posts 16, 25, 34.
I'm not sure where we're in disagreement.

No, no...I believe that WE are on the same page. My post above was simply another way to illustrate that Pounds per square inch is not the only thing to take into consideration. It was not pointed at you (or anyone for that matter).

 

[semipro]

No, no...I believe that WE are on the same page. My post above was simply another way to illustrate that Pounds per square inch is not the only thing to take into consideration. It was not pointed at you (or anyone for that matter).

Sorry for any misunderstanding.
I'd like to blame it on the communication mode but I don't do much better in person.

 

[Mykayel]

Did someone ask for a civil engineer?? I design structures, not pavement for a living, but I still remember my classes I took and in reality this is a structural question anyway. The size of the contact patch doesn't really matter its the total load from each axle that matters, so it is the big trucks that destroy the roads, cars really don't do anything.

Lets talk about concrete (asphalt is a little different as it is 'flexable' but similar concepts apply). Concrete is very strong in compression but only has about 1/10th its strength in tension (called its modulus of rupture). So if a tire is inflated to 35psi (or 100psi) this load over the contact area is very small compared to its compressive strength of about 4000psi (can be much higher but this is about normal strength). But this stress on the concrete doesn't really matter as concrete is good in compression. What matters is the tensile stresses that are created. Think of a patch of pavement as a beam that has to span from one section of soil (the compacted rock sub-base) to another patch of soil on each side of the axile load. The total load of the axle causes the pavement to bend and creates tensile stresses on the bottom side of the concrete. You could put some ultimate load that would cause the pavement to crack from this flexural bending stresses (the tensile stresses on the bottom side of the pavement). But what causes pavements to fail is fatigue, the loading and unloading stresses. And the larger the loading and unloading cycles are (i.e. the larger the total axle load is) the sooner it will fail in the flexural failure I described. A car's axle is so light compared to a big truck, that the amount of fatigue it induces on the pavement is virtually zero compared to the amount that a truck puts on the pavement. The axle load is what matters, not the load on the contact patch. The other thing that causes concrete to fail is the freeze thaw cycles and issues at the joints between pavement pieces.

If we really wanted to tax vehicles based on the wear and tear they put on the roads, then we wouldn't tax cars at all, we would only tax trucks. But the 'problem' is everyone including passenger vehicles benefit from the roads and use the roads. So the passenger vehicles should have to pay for something, especially to help build new roads. In my opinion, each vehicle (other than big trucks) should pay the same registration fee and there shouldn't be a use tax. Everyone benefits from the entire system of roads. But at the same time it only makes sense to have a little bit of a use tax as certain people benefit more from using the road system more. The easiest way to do that is a fuel tax or a per mile tax. I don't think its right for hybrid/electric cars to get a special tax because they use less fuel, based on this logic all fuel efficientvehicles should have a special tax. If a state is going to have a special tax, I think they really should just do tax per mile on a yearly basis for all vehicles.

 

[begreen]

Problem with the tax per mile is that some vehicles do a lot of out of state travel. It would hit the snowbirds traveling back and forth from NY to Florida harder for example.

 

[PapaDave]

As far as the road damage thing goes, drive your personal vehicle on a patch of dirt road or gravel drive or asphalt.
Then, invite a semi to drive on the same surface. Wait for a nice rainy day, or after a decent rain.
Your answer is in the result.
Any vehicle using the roads should be taxed in some way to help pay for the road and it's maintenance. Hybrids/electrics don't pay as much as a gas/diesel vehicle, but may drive as much or more.
Tax per mile wouldn't only be tougher on snowbirds.......folks who drive from metro Detroit to my neck of the woods for recreation might also pay more, just as they do now.
Should we have to pay fuel tax for lawn mower use.....chainsaw.....tractor, or any other device or vehicle that never sees or uses a road? I think not.
I don't have an answer to the question of how to tax road use, but lots of questions come up when the discussion starts.

 

[btuser]

Taxed per mile and paid every year when you register/inspect you car. Some of the money would get kicked upstairs to pay for interstates and whatnot. As far as out-of-state travel states would have to eat it, but it's in essence people bringing business/money into the state so other than a few extra in-coming toll roads I don't see it being a problem. People are gonna flip when it costs $2k to register a car.

I'm not going to let them put a meter in my car to let them know where I've been. Already got cell phone for that.

 

[Grisu]

I know I am asking for some beating but I would suggest: Increase the gasoline tax to offset the decline in revenue and push more people to buy fuel efficient cars. Do it in steps until most people drive high-mpg cars, but revenue stays the same. Advantages: Less pollution, less consumption of non-renewable fuels, less money going out of the country to buy oil (net import oil in 2012: 2.7 billion barrels; at $90 per barrel = $243 billion in "exported" dollar; US trade deficit 2012: $540 billion; that means oil imports are responsible for 45% of the trade deficit).

 

[begreen]

They will do more than flip. It already costs $2450 just in sales tax to buy a $25K car in the Seattle area. The last time the excise tax on car sales was even moderately high ($600 on a $30K car) a voter initiative killed the excise tax and left the entire transportation structure floundering (it still is in a world of hurt). Personally I would love to end the initiative process all together in this state. It is nothing but mindless populism. Most of the time folks don't even know what they are asking for or the consequences if the initiative passes.

 

[Seasoned Oak]

I know I am asking for some beating but I would suggest: Increase the gasoline tax to offset the decline in revenue and push more people to buy fuel efficient cars. Do it in steps until most people drive high-mpg cars, but revenue stays the same. Advantages: Less pollution, less consumption of non-renewable fuels, less money going out of the country to buy oil (net import oil in 2012: 2.7 billion barrels; at $90 per barrel = $243 billion in "exported" dollar; US trade deficit 2012: $540 billion; that means oil imports are responsible for 45% of the trade deficit).

Im right with you Grisu, Its simple and effective,the heavy gas guzzlers(which incidentally do more road wear) pay the most tax and it will hasten new tech into place faster such as the one listed. Even though i drive 2 gas guzzlers im all for rewarding those who dont.
http://gm-volt.com/2013/07/02/a-lit...ve-a-volt-120-miles-aer-seven-years-from-now/
New tech could wean us off all kinds of oil not just foreign oil.

 

[pyroholic]

Should we have to pay fuel tax for lawn mower use.....chainsaw.....tractor, or any other device or vehicle that never sees or uses a road? I think not.
I don't have an answer to the question of how to tax road use, but lots of questions come up when the discussion starts.

Is there such a thing as off-road gasoline just as there is off-road diesel. I've never seen it. Seems that an awful lot of gasoline gets put into OPE and such each year.