Four people were hurt in two early-morning crashes on Oahu, a bad sign for riders as moped and motorcycle injuries pile up.

• In Ewa, a 57-year-old man on a moped ran a red light while turning onto Fort Weaver Road and was hit by a car.
• He was thrown from the moped and is in critical condition; he was not wearing a helmet.
• Hours later, near the university in Manoa, a motorcycle carrying two riders crashed at Dole Street and University Avenue.
• A 20-year-old man and a 19-year-old woman on that bike were both taken to the hospital.

Outlook: Police are still investigating both crashes, and riding without a helmet remains the biggest factor in how badly people get hurt.