What is "Dooley tracks"?

It is not a fixed expression, but rather just the nickname of a type of vehicle used as a modifier before the noun tracks. These are tracks made by a "Dooley."

"What is a Dually Truck?"

If a truck is “dually,” it means it has dual rear wheels on either side. Badger

Officially, it was called the “1973 C-30 One-Ton Dually.” That's right. Most people refer to Chevy's pickups with the four wheels in the rear as a “Dooley or “Doolie"—and it's commonly spelled that way. Fact is, it's officially a “dually,” precisely because it has dual wheels on each rear side. aldanamerican.com; "A New Generation of Chevy Trucks, and Their First “Dooley” ";

Here is the clip from the Breaking Bad episode.