This chapter covers how alcohol and drugs impair driving, and the health factors — vision, hearing, and overall fitness — that affect safe driving. Alcohol slows reaction time, coordination, and the ability to judge distance, and even small amounts increase crash risk; only time removes alcohol from the body, so "sobering up" tricks like coffee or food don't work.
The most heavily tested material is the legal BAC (blood alcohol concentration) threshold: 0.08% for drivers 21 and older, and a much stricter 0.01% for drivers under 21. Refusing a breath test is itself illegal in New Jersey and carries its own penalties. The chapter also explains marijuana's effects on tracking, distance judgment, and divided attention, and reminds drivers that mixing alcohol with any drug — prescription or over-the-counter — is dangerous.
A common mistake is assuming that feeling "fine" or being under the legal limit means driving is unaffected — the manual stresses that alcohol impairs judgment starting well below 0.08%, and that food only slows (not prevents) a high BAC. Good hosts should stop serving alcohol before a party ends and never let an impaired guest drive.
What is the legal BAC limit for driving in New Jersey?⌄
0.08% or higher for drivers 21 and older; for drivers under 21, any BAC of 0.01% or higher is illegal.
Does eating food before drinking prevent a high BAC?⌄
No — food only slows how quickly alcohol enters the bloodstream. Heavy drinking will still produce a high BAC even with food.
How does marijuana affect driving ability?⌄
It can reduce lane-tracking ability, impair distance judgment, reduce vigilance, and make it harder to divide attention among traffic, road, and weather conditions.