Crash incompatibility, crash compatibility, vehicle incompatibility, and vehicle compatibility are terms in the automobile crash testing industry. They refer to the tendency of some vehicles to inflict more damage on another vehicle (the "crash partner vehicle") in two-car crashes. Vehicle incompatibility is said to lead to more dangerous, fatal crashes, while compatibility can prevent injury in otherwise comparable crashes.

The most obvious source of crash incompatibility is mass; a high mass vehicle such as a van or SUV will tend to cause much more serious damage in a crash with a lighter vehicle such as a typical sedan or compact car. Another potential incompatibility is in the specific shape, stiffness, or other design aspects of the impacting vehicles. For example, the higher ride of an SUV or pickup truck may lead to greater crash partner damage inflicted on cars with lower bumpers.

The design related incompatibility of SUVs has been somewhat exaggerated, but there is a real, statistical increase in crash partner mortality in accidents where an SUV strikes a traditional size vehicle, especially if the impact is to the driver side of the smaller car (or of course the passenger side if that side is occupied). These are increases in mortality even relative to comparably massive cars of more compatible shape, such as minivans. Thus this is cited as an example of shape/design related incompatibility.

Although much of the crash incompatibility debate in recent years has centered around SUVs, the concept has been around far longer. For example, when subcompact cars were introduced in the 1970s, there was fear that mass incompatibilties, and possibly design incompatibilities, could lead to more serious injuries for drivers of these smaller, lighter vehicles. Crash incompatibility is an area of active study, although to date only a small fraction of crash tests focus on two-car crashes, and an even smaller proportion are properly designed to address incompatibility issues.

See also

• car safety

External links

• For a recent report on vehicle incompatibility, see the April 4 2003 Status Report (Vol 38., No. 4) of the Insurance Institute for Highway Safety: http://www.hwysafety.org/srpdfs/sr3804.pdf.