The Doctor from "Doctor Who" has two hearts because he's from the planet Gallifrey. But why in the world do diesel trucks have two batteries?

Most vehicles have some sort of horn to alert other drivers, but why do semi trucks have huge, loud air horns? Turns out, there's a very good reason.

A deleted truck isn't a glitch on the road, but it's definitely something you don't want to be caught having. Here's what it means to have a deleted truck.

Many diesel enthusiasts who have modified their 6.7L Cummins engines report significant improvements in performance after performing a grid heater delete and upgrading their air intake horns.

The highest torque diesel engines ever made have turned up in everything from small commercial vehicles to powerful ...

California and President Trump are expected to clash over climate policies. The state just backed off on regulating diesel-powered semitrailers and buses.

California has decided to abandon its phase out of diesel trucks and requiring cleaner locomotives because of the incoming Trump administration.

President-elect Trump has threatened to revoke or challenge all zero-emission vehicle rules and California’s other clean-air standards.

Because Trump is unlikely to approve them, California has no choice but to abandon its groundbreaking rules for zero-emission trucks and cleaner locomotives.