Wipers On, Lights On: I-75 in a Downpour
Ten miles north of Macon on I-75, a summer thunderstorm drops visibility to roughly 200 feet in under a minute. Your wipers are on high, the air temperature is 78°F, and you are in the center lane at 55 mph. Standing water has pooled in the wheel ruts, and the steering went briefly light as your front tires crossed a puddle. Ahead, a sedan is running with no taillights, and a semi in the right lane is throwing a sheet of spray across your windshield. Your exit is two miles ahead and the shoulder is narrow with a guardrail. Traffic around you is still moving at highway speed.
1. What lighting must you have on, and why does it matter in this situation?
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Low-beam headlights. Georgia requires headlights whenever windshield wipers are in use because of rain, and this storm qualifies.
Why it matters: in heavy spray you are not the only one who cannot see - the semi's driver and the driver behind you need to see you. Parking lights or daytime running lights alone are not a substitute. Being visible is what keeps the sedan with no taillights from becoming your problem, and it keeps you from becoming someone else's.
2. The steering goes light as you cross a puddle. What is happening, and what do you do?
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You are hydroplaning: a film of water has lifted the tread off the pavement and the tires are no longer fully in contact. The light steering is the symptom.
Correct response:
- Ease off the accelerator smoothly - do not brake hard and do not jerk the wheel.
- Hold the wheel steady and let speed bleed off until the tires bite again.
- Once grip returns, reduce speed so you are not running in the ruts where water pools.
Braking or steering sharply while the tires are floating is how a hydroplaning car becomes a spin. Worn tread makes this happen at lower speeds and with less water.
3. Is 55 mph with a two-second following distance acceptable here? What would you change, and would you stop on the shoulder?
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No. The old "two seconds in good conditions" figure assumes dry pavement and clear sight lines; in this storm you want four or more seconds, and more still behind the semi's spray.
Changes: slow well below 55, drop back, and move away from the spray plume if a clear lane exists. The dark sedan ahead is a reason to increase the gap further - you cannot read its brake lights, so you must have enough room to stop on your own reference points rather than its signals.
Stopping on that shoulder would be a poor choice: it is narrow, walled by a guardrail, and adjacent to 70 mph traffic with 200 feet of visibility. If conditions deteriorate past what you can handle, take the exit two miles ahead and wait it out under cover.