Safe Driving Practices and Defensive Driving
Defensive driving is a search process
Teach students SIPDE: Search the scene, Identify hazards, Predict what each could do, Decide on a response, Execute smoothly. Pair it with the Smith System's five habits - aim high in steering, get the big picture, keep your eyes moving, leave yourself an out, and make sure they see you.
Space and time, not car lengths
Following distance is measured in seconds. Two seconds is the minimum in ideal conditions; four or more in rain, darkness, or behind a large truck; more still behind motorcycles and cyclists. Questions routinely offer "two car lengths" as a distractor. Never accept a following distance stated in lengths.
Hazards candidates forget
Big-rig no-zones (beside the cab, directly behind, ahead of the bumper), motorcycle stopping distances, the cyclist door zone, railroad crossings (never stop on the tracks; if stalled, get out and move away), hydroplaning (ease off the accelerator, no hard braking), and fatigue, which produces effects comparable to impairment and is not overcome by willpower.
Traps in wording
"The other driver had the right of way, so my student was not at fault" is never a valid defensive-driving answer. Neither is "honk and hold speed." Correct answers favor early, smooth adjustments that preserve an escape route.
Worked example
A student following a truck at 55 mph counts two seconds to a fixed object as the truck passes it. Is that adequate? Barely - and not behind a truck. The instructor should have the student drop back to at least four seconds, because the truck blocks forward visibility of hazards the truck driver already sees.
Rule of thumb
If you cannot stop within the distance you can see to be clear, you are driving too fast for conditions.