Honolulu police said a 65-year-old woman was critically injured over the Fourth of July weekend after sudden braking caused her to hit her head while riding on a public bus on Oahu.

Police said that at about 9:15 p.m. Sunday, the 51-year-old driver of an Oahu Transit Services bus — or TheBus — was traveling westbound on Kamehameha Highway in the Pearl Harbor area when he suddenly braked.

The woman was ejected from her seat into the aisle and struck her head. She was taken to a hospital in critical condition. No other occupants on the bus reported injuries.

Police said at this time, speed, alcohol or drugs do not appear to be contributing factors to the incident. An investigation is ongoing.

“The City reminds all drivers to drive with aloha and exercise care on our island roadways,” said Honolulu Department of Transportation Services in a statement. “Sudden stopping and unexpected movements around TheBus can lead to onboard injuries for all passengers, including our kupuna and keiki.”