co-driver

US /ˌkoʊˈdraɪ.vər/
UK /ˌkoʊˈdraɪ.vər/
"co-driver" picture
1.

a person who navigates for the driver in a rally or other motor race

:
The co-driver read out the pace notes to guide the rally car.
A good co-driver is essential for success in rally racing.