The event of an erection in a moving automobile despite the lack of pornographic or copulative activity.
In the current vernacular, it may be described as "having a boner in the car even when nothing sexy's going on".
It is caused by the vibrations caused by the movement of the car.
Dude, can you pull over? I've got some mad driving wood I need to take care of.
āDone with this shit man, Iām about to drive into the woodsā