A car is a fairly safe place to be. Although most of these are smaller than the main shock, some may be large enough to cause more damage. When the earthquake stops - Check your water line, gas line, and electrical lines. If there is a gas line into your home or building, turn off burners and pilot lights. Do not light candles, matches, or lighters until you determine there is no leak.
Gas leaks can cause explosions.
Report damage to the appropriate utility companies and follow their instructions. If there is a leak, stay out of the house. Do not flush toilets until you know that sewer lines are unbroken. Electric lines can cause fire. Shut off all electrical power if there is damage to your house wiring.