Change.gov Options

[Mommy]

http://www.change.gov/


Click on agenda... read and post thoughts

[Billy]

Heavy trucks damage the roads far greater than light cars. Simple fatigue analysis. Any engineer can you tell you that. Not only that, but roads and bridges have to be designed for the greater weight of trucks, thus increasing the cost of building roads.

Here's some perspective: Average weight of a car: 4500 lbs
Average weight of one our manifolds that we ship via road: 145,000 lbs.

But the little passenger cars have to pay much more than they should have to so that the roads can handle in excess of 145,000 lbs.

[Dogmeat]

Heavy trucks damage the roads far greater than light cars. Simple fatigue analysis. Any engineer can you tell you that. Not only that, but roads and bridges have to be designed for the greater weight of trucks, thus increasing the cost of building roads.

So there is a vast amount more usage of the roads of non-DOT vehicles, meaning vehicles with a GVWR of less than 10,000 lbs. Anything 10k or over you have to have a CDL to legally operate on public roads.

A fully loaded semi truck is bound by law to be less than 80,000-lbs gross without an overload permit, so I'm going to use this as a base number.

I'm going to assume the average weight of a passenger car is 3500-lbs.

I am going to assume that the average contact patch for non-DOT vehicles is a 6.5" wide tire, and a 24" diameter. So, just for the hell of it, let's assume a contact area of 6.5"x4"x4. 104" in^2 x 3500-lbs = a stress of 33.65 psi exerted on the roadways. Now, for the hell of it, lets take that stress exerted on the roadways times the number of miles driven ... 33.65 psi x 1,682,671 Mmiles = 55,621,879 psi*Mmiles

Now let's do the same thing to come up with a represenative "damage factor" for DOT vehicles.

A semi tire is approximatley 11" wide by 38" in diamater. Let's assume a contact area of 11x8x10 (tractor) + 11x8x8 (trailer) ... 18 total wheels, for a total area of 1584 in^2.

80,000-lbs / 1584 = 50.5 psi.

Let's apply our 'damage factor' calculation.

50.5 psi x 80,331 Mmiles = 4,056,715 psi*Mmiles

Damage factors:

Passenger cars - 55,621,879 psi*Mmiles
DOT vehicles - 4,056,715 psi*Mmiles

Pcar / Dot Damage ratio ------ 13.7 x more stress on roadways due to passenger cars than DOT rigs.

Thank you drive thru!