Sounds like Max got hungry and decided to go across the street for a bite to eat at the fast food place. Very smart of him to take the truck. Much safer than trying to cross the street by himself.

Thanks to Lynn H. for barking in this article from CNN.

Truck with dog at wheel backs through traffic unharmed
AZUSA, California (AP) — Doggone it, my truck’s gone!

Can Boxers drive? One in California knocked a truck out of gear and rolled across a street full of traffic unharmed.

Police said Charles McCowan parked his pickup in front of a mini-mart Wednesday, leaving his 80-pound Boxer named Max in the passenger seat.

When he came out, the truck and Max were gone.

McCowan called police, assuming the truck had been stolen.

When officers arrived, they found the pickup across the street in a fast-food parking lot but had no idea how it got there.

In security video shown Thursday on KCAL-TV, the truck can be seen rolling backward out of the store lot and across the street, threading its way through traffic and out of view.

Police said that after McCowan left the truck, Max knocked the vehicle out of gear and sent it rolling backward.

Both the dog and the truck emerged without a scratch.