WAIALUA (HawaiiNewsNow) - Police say speed is likely what caused a car crash early Saturday morning that killed a 28-year old female in Waialua. It happened around 2:30 a.m. on Kaukonahua road near Wilikina Drive. Traffic investigators say the 28-year old was speeding when she lost control of the vehicle, hit a guardrail, flipped over, and skidded to rest. The driver was ejected from the vehicle and pronounced dead at the scene. Police say she was not wearing a seatbelt. Her 21-year old female passenger, who was wearing a seatbelt was taken to the hospital in serious condition. It is not yet known if drugs or alcohol were factors in the crash.