A 37-year-old Mililani woman sustained critical injuries Sunday after crashing her motorcycle in the Mililani Tech Park area, police said.

The woman aparently lost control of the motorcycle on Wikao Street sometime before noon and it hit a curb and then a tree, police said.

A bystander who did not see the crash found her unresponsive on the ground and called for help, according to Emergency Medical Services. She suffered head trauma and was transported in critical condition to a hospital. 

The woman had been wearing a helmet, police said.