passed / past
The verb versus the adjective, noun, and preposition.
Passed is the past tense and past participle of pass: She passed the truck. The bill was passed. Past is the adjective, the noun, or the preposition: the past week, in the past, past the gate. Do not write past for the verb.
Examples
Use He passed the exit.
Use Drive past the exit.
Avoid He past the exit.