Using the chairlifts or gondola lifts at a ski area, mountain bikers can get up to higher altitudes quickly.
The bikers don't have to ride up, and the ski area operators can keep the hill more profitable during the summer.
Most bike parks have a mix of dirtjumping, downhill, enduro and freeride terrain on the trails.
Many ski resorts have embraced the sport, opening the chairlifts and building trails to rider in the summer.
Lift-accessed bike parks are good because they offer the chance to make many more runs down a mountain than could be done without use of a lift.