Turn signal — before a turn3–4 sec (~100 ft)
Following — under 35 mph2 seconds
Following — 35–45 mph3 seconds
Following — 46–70 mph4 seconds (more in rain)
School bus w/ flashing redsStop from any direction
Pass bicyclist / horse buggy3 feet minimum
Visibility < 500 ftHeadlights on
Dim beams — oncomingWithin 500 feet
Dim beams — followingWithin 200 feet
Headlight hoursSunset to sunrise
Using wipers for weatherHeadlights required
Pass cyclist clearance3 feet
No parking — railroad crossingWithin 50 feet
Follow emergency vehicleNever closer than 500 ft
💡 Virginia's space-cushion rule does not work over 70 mph. In rain, fog, heavy traffic, behind a motorcycle/bicycle, or when tailgated, add time. Hand response ≈ ½ sec, foot response ≈ ¾ sec — before any perception delay.