Tough choice there. I'd say you need to go with what's more likely to kill you in your car. A BG or a crash?
Maybe if the public knows about the problem someone will invent a better mousetrap for police cruisers. My first though is just a single padded chest trap that rides across the torso up high. My idea (in my head) looks like the old lap belt but is padded and is attached to the seat up high. It would come under the armpits and buckle across the chest.