In the "Study to Predict the Electromagnetic Interference for a Typical House in 2010", the author, Anita Woogara at Bristol University, says:
Cars and other vehicles now contain many electronic systems. These range from electronic engine management systems to achieve maximum efficiency to electronically operated airbags to protect the driver in the event of a crash. Unfortunately this leaves cars more vulnerable to electromagnetic interference. Mobile phones and passing taxi radios have been known to interfere with Anti-skid Braking Systems (ABS) and airbags, causing drivers to lose control of the car. Car ignition has been changed recently to a short high voltage spark, although better for exhaust emissions this causes wideband interference. As the car industry is very competitive, cutbacks are often made on the wiring, which increases the risk of susceptibility.The inclusion of computers in cars for navigation purposes will also increase the susceptibility.
Automobiles are covered in the Automotive Directive; this excludes them from the EMC Directive on sub-assemblies and devices that may be sold separately from the vehicles. All of the systems in the car have to be able to work simultaneously without interference from each other; ignition interference and external radiated interference. However, interference from objects brought into the car, such as mobile phones and laptops, may have been missed out. Additionally, household electronics can be affected by cars outside, in the street or garage, which is especially relevant in houses with small front gardens.