(1977) The Gauntlet

A cop who has seen better days, hard-living Ben Shockley (Clint Eastwood) is recruited to escort Augustina "Gus" Mally (Sondra Locke), a key witness in a mob trial, from Las Vegas to Phoenix. Gus is a beautiful but coarse call girl who claims to have information that makes the two highly expendable targets. Ben starts to believe her after numerous attempts are made to kill them as they travel across the unforgiving desert, pursued by angry bikers and corrupt police officers.