Development of standards for commercial medium-duty and heavy-duty vehicles.

In case of light-duty trucks, all 3 conditions must be met, otherwise it is classified as heavy-duty vehicle.

They are still used today on most trucks and heavy-duty vehicles.

Fuel economy regulations do not apply to heavy-duty vehicles, so they are not tested.

What they needed was some kind of heavy-duty all-terrain vehicle, but these had all been comman- deered for use at the site.

They are heavy-duty vehicles with large engines and several axles.

Having grown up on a citrus ranch, he learned to drive a 10-speed farm truck at age 12, so heavy-duty vehicles always appealed to Chuck.

Now we are looking at heavy-duty vehicles.

This is certainly the case for heavy-duty vehicles.

Certainly in terms of noise, heavy-duty vehicles play a key role.