No. Other than a basement or a tornado/storm shelter the inside of a motor vehicle is one of the safest places to be in an electrical storm. This is not due to the insulating property of the rubber tires but to the Faraday effect of the vehicle's metal exterior. The metal exterior of the vehicle acts as a Faraday cage, diverting any electrical discharge around the vehicle. The Faraday effect also protects airplanes that fly through electrical storms.
If you can't seek shelter during a storm then get down on the ground or in a ditch, away from any trees, pavilions, antennas, etc. Make yourself as low to the ground as possible. Recently a group of four people unwisely took shelter from a storm under a cluster of trees in a park. Lightning struck the tree killing three of the four people.
