Following Distance on a Rainy Highway
You are driving on an interstate at 65 mph in steady rain. Your wipers are on, headlights are on, and the road surface is visibly wet with some standing water in the wheel ruts. Traffic ahead is heavy but moving. The car directly in front of you is a large box truck that sprays water and blocks your view of the road beyond it. You have been using a two-second following gap.
1. Is a two-second gap adequate here? What should you change and why?
Read the worked answer
No. Two seconds is a fair-weather minimum for a light vehicle at moderate speed. Wet pavement lengthens stopping distance, and the box truck both blocks your forward view and throws spray that reduces visibility. Increase the gap substantially - aim for at least four seconds, and more if spray is heavy. The larger gap buys you reaction time, restores some sight line around the truck, and keeps you out of the worst spray. You can check it by counting the seconds between the truck passing a fixed object and you reaching it.
2. What specific hazard does the standing water in the wheel ruts create, and how do you manage it?
Read the worked answer
Standing water raises the risk of hydroplaning, where the tires lose contact with the pavement and steering and braking become ineffective. Manage it by reducing speed, avoiding abrupt braking or steering, and not driving through deep water in the ruts if you can shift to a higher, drier part of the lane. If you feel the wheel go light or the car start to wander, ease off the accelerator smoothly and hold the wheel steady until traction returns - do not stomp the brakes.