Traffic Enforcement and Crash Investigation
Traffic Enforcement and Crash Investigation
This domain tests the impaired-driving statutes, lawful stop and testing procedure, and the mechanics of documenting a crash so it holds up in court.
OUI essentials
- M.G.L. c. 90 § 24: operation, on a public way (or a place the public has a right to access), while under the influence. Per se limits are .08 for adults, .04 for commercial drivers, and .02 for junior operators under c. 90 § 24P.
- Melanie's Law (2005) added ignition interlock and child endangerment, c. 90 § 24V.
- A first-offense CWOF under c. 90 § 24D requires an alcohol education program.
- Refusal of the breath test is admissible at trial and triggers suspension: 180 days, then 3 years, then 5 years, then lifetime.
- Standardized field sobriety tests are HGN, walk-and-turn, and one-leg-stand. Document the clues, not just the conclusion. Breath testing follows the Office of Alcohol Testing protocol, including a 15-minute observation period.
Crashes
- Operators must report crashes involving injury, death, or property damage over $1,000 to the Registry under c. 90 § 26; the department forwards its own report.
- Leaving the scene: c. 90 § 24(2)(a) for personal injury, § 24(2)(b) for property damage.
- Speed from skid marks: S = √(30 × d × f), with d in feet and f the drag factor. State your assumptions.
Worked example
A car is in a ditch, engine still warm, the driver gone, a passenger injured. Operation is proved circumstantially through position, damage, keys, and statements, and the charge is leaving the scene of personal injury under § 24(2)(a). Operation need not be observed directly.
Traps
Failing to record pre-stop driving observations; treating refusal itself as an admission of guilt; skipping the observation period; omitting the drag factor assumptions from the reconstruction.