How would you mulch a hillside with a 20% grade adjacent to a neighbor's driveway?

We have relatively new neighbors in the house behind us. He's a pastor and they frequently host new visitors from church. Their driveway is about 125 feet long and just as steep (20%). Most drivers out here have never backed up such a long distance and certainly not downhill. When they veer off course, the fir chips currently in place either get crushed or sometimes flung all over the place if they spin their tires pulling forward again.

The tendency for the chips to wash away is much worse when they've been recently disturbed by car tires. This sets off a chain reaction with fir chips several feet from the driveway getting displaced. In years past, they settled in place and weren't so prone to floating because car tires never left the pavement.

I'm contemplating moving the fir chips to a different part of the yard and using some other kind of mulch along the driveway. Looking for a mulch suggestion that is dark brown/reddish, stays put reasonably well on hillsides, lasts a long time, and preferably can withstand being run over by a car once in a while.

Alternatives to solve this problem are also welcomed.