When you are driving a vehicle the vehicle needs to contain dashcam. This will be a big indication of what is happening and what the vehicle that is getting near to you is. While you have a dashcam they will not drink a lot of battery. The battery that the cam will take is from the battery from your car.
Before painting a vehicle sanding away the car paint by properly using sandpaper to smooth the cracks and other imperfections in the vehicle is probably the most important thing. If once the car has been painted the sanding problem will be noticed easily and it will require sand again and start over.