Kaua'i police suspect speed and alcohol contributed to a single-vehicle crash resulting in critical injuries to the driver early Tuesday morning on Kuhio Highway near the South Leho junction in Wailua.

The driver, a 20-year-old man, was medevaced to The Queen's Medical Center following the 2:47 a.m. crash. His current condition is not known.

Another man, 25, who was a passenger in the vehicle, was treated for injuries at Wilcox Hospital and released.

Police said the driver apparently lost control of the vehicle, which went off the highway.