Honolulu police are investigating a hit-and-run crash that left a 57-year-old moped rider on Kalanianaole Highway in serious condition Tuesday.

Police said that at about 2:50 p.m., an unidentified motorist hit a female moped rider while attempting to overtake her heading westbound on Kalanianaole Highway near Halona Blowhole in East Oahu.

The motorist continued westbound without stopping to render aid or provide information, even though the moped rider had been thrown onto the highway, police said.

Honolulu Emergency Medical Services took the woman to the hospital with serious injuries. Police said she declined to seek prosecution.

Police said speed appears to be a contributing factor in the collision. The moped rider was wearing a helmet.