Defensive driving is a system of techniques designed to help you anticipate and avoid hazards before they become emergencies. The state DMV permit test rewards defensive answers — when in doubt on a scenario question, the slower, more cautious option is almost always correct.
SIPDE
Most driver handbooks teach the SIPDE process: Search, Identify, Predict, Decide, Execute. Search the road and shoulders ahead. Identify potential hazards. Predict what could happen. Decide what to do. Execute the action smoothly. [Recommended driving resource] This is essentially the framework that the test asks you to apply on every scenario question.
The 12-second scan
Look at least 12 seconds ahead in city driving and 20-30 seconds ahead on highways. At highway speed, 12 seconds is roughly a quarter mile. Looking that far ahead lets you see brake lights, lane changes, and obstructions early enough to slow gradually instead of stopping suddenly.
The 3-second following rule
Maintain at least three seconds of following distance behind the vehicle ahead in good conditions. To measure: when the vehicle ahead passes a fixed object (sign, tree, lane marker), count "one-thousand-one, one-thousand-two, one-thousand-three." If you reach the object before you finish counting, you're too close.
When to extend to four or more seconds
Double the following distance to four to six seconds in rain, snow, fog, heavy traffic, or at night. Truck drivers and motorcyclists need additional space — drop back further when following or being followed by either.
The two-second mirror check
Check your mirrors every five to eight seconds in normal driving. Always check before braking, before turning, before changing lanes, and after passing a hazard. The blind-spot check (over your shoulder) takes priority over the mirror check before any lane change.
Hazard recognition
Common hazards: a ball rolling into the street (a child is likely to follow), a parked car with brake lights or smoke from the exhaust (it may pull out), a vehicle weaving in its lane (impaired or distracted driver — back off), and a wide gap in oncoming traffic at a green light (cross-traffic may be running the red and creating the gap).
Emergency maneuvers
In an emergency, slow first if you can — most rear-end and side-swipe collisions are at lower closing speeds when the driver brakes early. If you must steer to avoid a hazard, look where you want to go, not at the hazard. Drivers who stare at the obstacle they want to miss almost always hit it.
What the test rewards
Whenever a scenario question offers a choice between speeding up to clear a hazard and slowing down to give yourself time, the slower answer is almost always correct. When in doubt: slow, scan, and signal.