Speed and drugs appeared to be factors in a head-on collision near Kalama Valley Wednesday night, police said.
The crash occurred on Kealahou Street, south of Kalohelani Place at about 7:25 p.m.
Police said a Volkswagen sedan operated by a 25-year-old man was traveling northbound on Kealahou Street when it veered into the opposite lane and collided head-on with a Ford MPVH.
The Volkswagen driver was initially taken to a hospital in critical condition and his 18-year-old male passenger was transported in serious condition.
Police said the Ford driver, a 68-year-old woman, and her female passenger, also 68, were also taken to a hospital in serious condition.
The drivers and passengers in both vehicles later improved to good condition.
Police said speed and drugs appeared to be factors in the crash on the part of the Volkswagen.
Police are continuing their investigation.