EMP ATTACK! Is Your Car EMP Proof?

Automobiles

The potential EMP vulnerability of automobiles derives from the use of built-in electronics that support multiple automotive functions.  Electronic components were first introduced into automobiles in the late 1960s.  As time passed and electronics technologies evolved, electronic applications in automobiles proliferated.  Modern automobiles have as many as 100 microprocessors that control virtually all functions.  While electronic applications have proliferated within automobiles, so too have application standards and electromagnetic interference and electromagnetic compatibility (EMI/EMC) practices.  Thus, while it might be expected that increased EMP vulnerability would accompany the proliferated electronics applications, this trend, at least in part, is mitigated by the increased application of EMI/EMC practices.

We tested a sample of 37 cars in an EMP simulation laboratory, with automobile vintages ranging from 1986 through 2002.  Automobiles of these vintages include extensive electronics and represent a significant fraction of automobiles on the road today.  The testing was conducted by exposing running and nonrunning automobiles to sequentially increasing EMP field intensities.  If anomalous response (either temporary or permanent) was observed, the testing of that particular automobile was stopped.  If no anomalous response was observed, the testing was continued up to the field intensity limits of the simulation capability (approximately 50 kV/m).

Automobiles were subjected to EMP environments under both engine turned off and engine turned on conditions.  No effects were subsequently observed in those automobiles that were not turned on during EMP exposure.  The most serious effect observed on running automobiles was that the motors in three cars stopped at field strengths of approximately 30 kV/m or above.  In an actual EMP exposure, these vehicles would glide to a stop and require the driver to restart them.  Electronics in the dashboard of one automobile were damaged and required repair.  Other effects were relatively minor. . Twenty-five automobiles exhibited malfunctions that could be considered only a nuisance (e.g., blinking dashboard lights) and did not require driver intervention to correct.  Eight of the 37 cars tested did not exhibit any anomalous response.

Based on these test results, we expect few automobile effects at EMP field levels below 25 kV/m.  Approximately 10 percent or more of the automobiles exposed to higher field levels may experience serious EMP effects, including engine stall, that require driver intervention to correct.  We further expect that at least two out of three automobiles on the road will manifest some nuisance response at these higher field levels.  The serious malfunctions could trigger car crashes on U.S. highways; the nuisance malfunctions could exacerbate this condition.  The ultimate result of automobile EMP exposure could be triggered crashes that damage many more vehicles than are damaged by the EMP, the consequent loss of life, and multiple injuries.

Trucks

As is the case for automobiles, the potential EMP vulnerability of trucks derives from the trend toward increasing use of electronics.  We assessed the EMP vulnerability of trucks using an approach identical to that used for automobiles.  Eighteen running and nonrunning trucks were exposed to simulated EMP in a laboratory.  The intensity of the EMP fields was increased until either anomalous response was observed or simulator limits were reached.  The trucks ranged from gasoline-powered pickup trucks to large diesel-powered tractors.  Truck vintages ranged from 1991 to 2003.

Of the trucks that were not running during EMP exposure, none were subsequently affected during our test.  Thirteen of the 18 trucks exhibited a response while running.  Most seriously, three of the truck motors stopped.  Two could be restarted immediately, but one required towing to a garage for repair.  The other 10 trucks that responded exhibited relatively minor temporary responses that did not require driver intervention to correct.  Five of the 18 trucks tested did not exhibit any anomalous response up to field strengths of approximately 50 kV/m.

Based on these test results, we expect few truck effects at EMP field levels below approximately 12 kV/m.  At higher field levels, 70 percent or more of the trucks on the road will manifest some anomalous response following EMP exposure.  Approximately 15 percent or more of the trucks will experience engine stall, sometimes with permanent damage that the driver cannot correct.  Similar to the case for automobiles, the EMP impact on trucks could trigger vehicle crashes on U.S. highways.  As a result, many more vehicles could be damaged than those damaged directly by EMP exposure.