The Grapevine is a serious hill at 6% for 5+ miles - but there are no bad curves. The thing that might unnerve some folks is the heavy truck traffic and trucks suddenly pulling out to pass. Climbing up southbound, there are two or three "water holes" (pull outs where radiator water is available). These are hold overs from the days when under powered cars and trucks would overheat during the climb. These offer a place to get out of traffic - if needed. There is also a rest area near the top, truck stops and restaurants just below the summit and a truckers' brake check area at the summit. Descending the mountain into the San Fernando Valley is 5+ miles of 6% with a truck speed limit of 35mph - so watch for those slow moving trucks. Like any long hill, watch your temps, watch your speed and be willing to get out of the way of the big rigs - in case he is losing or has lost his brakes.
