This guide covers traffic and impaired driving law from the stop through the collateral consequences, for the driver, the defense lawyer, and anyone advising either. Part 1 explains the two-case structure and the administrative deadline that ends more license cases than any argument ever made. Part 2 covers the stop, reasonable suspicion, the pretext rule, checkpoints, and where cases are actually won. Part 3 covers the roadside investigation and what field sobriety tests actually measure, along with the custody line that determines whether warnings were required. Part 4 covers implied consent, the constitutional distinction between breath and blood, the warrant question, and the right to independent testing that is rarely offered. Part 5 covers chemical evidence, the per se limit, retrograde extrapolation, and the specific attacks available on a test result. Part 6 covers the administrative license proceeding as agency adjudication and why it is the cheapest discovery in the case. Part 7 covers the criminal case, the discovery that expires, and the suppression sequence, and Part 8 covers disposition, diversion, and sentencing. Part 9 covers commercial drivers, minors, and repeat offenses, and Part 10 covers ordinary traffic offenses, points, and the suspension-by-accumulation problem that fills criminal dockets.