To do it properly, the government would need to install three cameras (front, rear, and interior), breathalyzer, and a transmitter. Place receivers on bridges, on ramps, and tunnels (for tolls), overpasses (for speeding tickets), road signs (to manage compliance with local traffic regulations), and anywhere else deemed necessary and proper to monitor the safety, security, and movement of the national population. Tickets automatically issued for violation would include pictures of the driver, passengers, and vicinity, along with the relevant GPS data. Cellphone usage would be monitored, as well, in order that the appropriate fines may be allocated for distracted driving. Internal sensors for smoke, food, and sugary drinks will be added, of course, once regulations detailing their lawful usage have been put in place on a national level.
Being freed of traffic duty, local police may then be integrated into federal 'Action Forces', which will be able to prosecute more serious crimes against society - such as murder, rape, and failure to pick up after your dog.