Rockcrawling is an extreme form of off road driving. Drivers use vehicles anywhere from stock to highly modified to overcome obstacles (usually rocks). In rock crawling, drivers drive highly modified four-wheel drive vehicles such as trucks, Jeeps, and "buggies" over very harsh terrain. Driving locations include boulders, mountain foothills, rock piles, mountain trails, etc. Rock crawling is about slow-speed, careful driving. Rock crawlers often drive up, down and across obstacles that would appear impassable. Such vehicles to rock climb are primarily 4x4s.