head-on       
adjective [ before noun ], adverb uk/ˌhedˈɒn/ us/ˌhedˈɑːn/
 (事故)迎头相撞的,正面相撞的
A head-on accident is one in which the fronts of two vehicles hit each other.
  The car crossed the road and hit a truck head-on. 汽车横穿马路迎头撞上了一辆卡车。 
 a head-on collision 迎头相撞