AMBUSH ON HIGHWAY 1* * United States Army Advance* ___________vs.* ___North Vietnam Delay* * Date: November 20, 1966* * Location: Vietnam* * Highway 1 was the main artery along the coast of South Vietnam. The Viet Cong regularly shut down the road. Elements of the U.S. 11th Cavalry were used as a "reconnaissance in force" to keep the highway open, while "Charlie" often waited in ambush.