Is my Peterbilt 379 considered a "heavy truck over 13,000 lbs" or a "truck tractor for over-the-road use" if I am a local owner-operator not an over-the-road driver?

IRS Publication 946 doesn't truly state the difference between a Truck or Trailer.
Appendix B, 00.242...
Trucks (over the road)... 5 years
Trailers(-mounted containers) ... 5 years
Tractor units... 3 years

Posting from an online blog article re: Trucking for Businesses:
"...  a number of accountants had recommended the 3 year election on trucks and the 5 year on trailers while others recommended 5 years on both. I wanted to make sure I had my facts straight so I looked through the laws and instructions from the IRS and found that the confusion lies largely in the fact that a "Tractor" is a 3 year asset, while a "Truck" is a 5 year.  The majority of drivers refer to their truck as a 'tractor-trailer', so in being told that the truck is a tractor, the accountants are classifying the trucks as tractors."

Bonus Depreciation is applicable for Federal tax purposes or S179 or regular depreciation, depending on your choice and client's tax planning for future budgeting.
Be cautious as certain States do Not conform with the Federal Bonus Depreciation laws but S179 is allowable by many but may be more limited.