I'm really glad someone else has noticed this. This is about as real as GMW gets lol.
This has been happening since Doomsday Heist, I've noticed it a few times. It's definitely something to do with the presence of the police, at least the police have been in the vicinity every time I witnessed it.
Are you in a public lobby with other players? If you are, it's potentially because someone has started the CEO Work 'Haulage'; that mission clears a route of traffic and the GOH is one of the possible routes. My only guess for the random direction is likely the script forcing drivers to leave the area rather than despawn in view, given traffic spawns elsewhere in the mission.