ride shotgun

Meanings

1. To accompany the driver of a vehicle on a journey as an armed escort (originally with a shotgun); (by extension) to accompany someone in order to assist and protect.
2. To ride in the front passenger seat of a vehicle, next to the driver.
3. To supervise a process and watch for any risks.

Etymology

Possibly from early-20th-century depictions in books and films of the 19th-century practice of a person armed with a rifle or shotgun riding next to a stagecoach driver to provide protection from bandits, etc.