IIRC Jeeps get benefits for shooting at moving snipers. Also, like bikes, they have an incremental accuracy mod of <1. This means that while every other unit gets bonus damage when they shoot at larger and larger numbers of units (blob control), bikes and jeeps deal more damage to single, solitary units.
M16? Are we talking about the same game here?
also a little tip with jeeps that i like to use, with a little bit of micro you can use jeeps to "push' units out of cover, or push them to prevent them from firing a panzerfaust/panzershreck or throwing a grenade