 The parkway was controversial in its construction and was challenged in court several times before a compromise was met between the state and the Sierra Club, which limited the speed on the road and banned semi-trucks on the highway except in emergencies.In addition to the restrictions on speed and trucks, the road was reduced from a six-lane expressway to a four-lane parkway.The compromise agreement restrictions have a sunset date of January 1, 2020, at which time the speed limit will increase to and trucks will no longer be banned.