What should I do if I am driving during an earthquake?

If you are driving pull over to the side of the road, stop, and set the parking brake. Avoid overpasses, bridges, power lines, signs and other hazards. Stay inside the vehicle until the shaking is over. If a power line falls on the car, stay inside until a trained person removes the wire.

What to do if you are Driving During an Earthquake
A link to Putting Down Roots in Earthquake Country.

LAFD Earthquake Handbook: Earthquake Tips
What to do during an earthquake if you are in a high-rise building, on a sidewalk near buildings, outdoors, driving, in a store or crowded public place, in a wheelchair, in the kitchen or in a stadium or theatre. Also has a post-quake checklist.