Were you shooting through the windshield? LOL busting your balls but I am not getting the utility of trying to shoot while driving, other than Hollywood stunts. That said I did once have to draw a .357 on a carload of meth-head hillbillies who were having some sort of road rage problem on remote section of I-40 in Tennessee. That was to change their mind about trying to force me to stop.A smaller Fanny Pack is also good for driving. You wear it over your belly and put the seat belt below it on your lap. Much easier to rip open and draw from than a belt holster. We did that at NFGA decades ago with a SIG guest instructor, John Peterson. You grab the wheel with you left hand, rip open the fanny pack with your right, draw and shoot. Yes, you muzzle your own arm once. Big Boy rules. Presumably, someone is a threat to your life if you draw in your car. Tactically, the other option is pop your seat belt to enable a holster draw.
Back when I had a MA Non-Res LTC, I Fanny Pack carried on my MHT-BOS-MHT drive and switched to belt holster outside the car. I also have a super-small fanny pack that fits under a T-shirt. If I cinch it down, I can jog with a P365 without any flop. Kind of like those belly-band holsters that don’t work for me.