Q: What about trucks?
A: It's more complicated.
For standard-duty models — most SUVs, vans and pickups:
1. The old one must be rated 18 mpg or less.
2. The new one must be at least 2 mpg better for $3,500 or at least 5 mpg better for $4,500.
For heavy-duties (6,000 to 8,500 pounds gross vehicle weight rating):
1. The old one must be rated 15 mpg or less.
2. The new one must be rated at least 1 mpg better for $3,500, or 2 mpg or more for $4,500.
Work trucks (8,500 to 10,000 lbs.) don't have mpg ratings, so age is the criteria. The old one has to be a 2001 model or older. And only $3,500 is available.