Another "myth" that seems to have grown up with information on EMP is that nearly all cars and trucks would be "knocked out" by EMP. This seems logical, but is one of those cases where "real world" experiments contradict theoretical answers and I'm afraid this is the case with cars and EMP. According to sources working at Oak Ridge National Laboratory, cars have proven to be resistant to EMP in actual tests using nuclear weapons as well as during more recent tests (with newer cars) with the US Military's EMP simulators.

One reason for the ability of a car to resist EMP lies in the fact that its metal body is "insulated" by its rubber tires from the ground. This creates a Faraday cage of sorts. (Drawing on the analogy of EMP being similar to lightning, it is interesting to note that cases of lightning striking and damaging cars is almost non-existent; this apparently carries over to EMP effects on vehicles as well.)

Although Faraday boxes are generally made so that what is inside doesn't touch the box's outer metal shield (and this is especially important for the do-it-yourself since it is easy to inadvertently ground the Faraday box—say by putting the box on metal shelving sitting on a concrete floor), in the case of the car the "grounded" wiring is grounded only to the battery. In practice, the entire system is not grounded in the traditional electrical wiring sense of actually making contact to the earth at some point in its circuitry. Rather the car is sitting on insulators made of rubber.

It is important to note that cars are NOT 100 percent EMP proof; some cars will most certainly be affected, especially those with fibreglass bodies or located near large stretches of metal. (I suspect, too, that recent cars with a high percentage of IC circuitry might also be more susceptible to EMP effects.)

The bottom line is that all vehicles probably won't be knocked out by EMP. But the prudent survivalist should make a few contingency plans "just in case" his car (and other electrical equipment) does not survive the effects of EMP. Discovering that you have one of the few cars knocked out would not be a good way to start the onset of terrorist attack or nuclear war.

Most susceptible to EMP damage would be cars with a lot of IC circuits or other "computers" to control essential changes in the engine. The very prudent may wish to buy spare electronic ignition parts and keep them a car truck (perhaps inside a Faraday box). But it seems probable that many vehicles WILL be working following the start of a nuclear war even if no precautions have been taken with them.