Built into the Insurance Services Office, Inc. (ISO), commercial general liability (CGL) policy coverage part for over 35 years is an "Aircraft, Auto or Watercraft" exclusion -- currently labeled as exclusion g. in the Commercial General Liability Coverage Form (CG 00 01 04 13).

While it is apparent from its title that this exclusion applies to aircraft and watercraft as well as autos, this article will focus on how the exclusion applies to autos.

Further, even though "auto" is defined in the CGL policy, presume the vehicles in this discussion all fit that definition of "auto." To better understand the definition of "auto" or to review a comparison of "auto" to "mobile equipment," see "Auto versus Mobile Equipment in the CGL."

The basic purpose of the CGL policy auto exclusion g. is found in the first paragraph of the exclusion. One commentator offered that the simplest way to phrase the meaning of the exclusion is to say there is no coverage when bodily injury or property damage is caused by the operation or use of a vehicle by an insured.