A 75-year-old woman was critically injured in a hit-and-run collision Friday evening along Farrington Highway in Nanakuli.

The woman was riding a motorized mobility scooter when she started to cross the highway near Princess Kahanu Avenue around 6:47 p.m. and was struck by a vehicle traveling eastbound at high speed, according to the Honolulu Police Department.

The initial collision caused the woman to be thrown from her scooter, police said. She was then hit by a second vehicle, driven by a 69-year-old man, who had been following behind the first motorist. The second driver remained at the scene, but the first driver fled without stopping to provide aid.

Honolulu Emergency Medical Services responded to the scene and reported the woman suffered extensive critical injuries to the lower half of her body, police said. Paramedics applied tourniquets, administered advanced life support and transported her to a hospital in critical condition.

The motorist who fled the scene is believed to have been driving a white Chevrolet Silverado, according to HPD. The woman was not in a marked crosswalk at the time of the collision. The 69-year-old driver and his 55-year-old female passenger were not injured.

Speed appears to be a factor in the crash, but it is not yet known if drugs or alcohol played a role, police said. The investigation is ongoing.

Anyone with information is urged to contact the Honolulu Police Department’s Traffic Division at (808) 723-3413.