Night Driving With a Misaimed Headlight
You are driving a light truck on an unlit two-lane highway at night at 90 km/h in a 90 km/h zone. Your right low-beam headlight is aimed too high after a recent bump, and oncoming drivers have been flashing their high beams at you. The left headlight is fine. The road curves gently right, and deer are common in this area. Your windshield has a light film of grime. You are within the first hour of a two-hour trip.
1. Oncoming drivers keep flashing their high beams. What is happening and what should you do?
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They are telling you your lights are glaring them - likely your misaimed right low beam, possibly combined with grime scattering light. The correct response is to check that you are not on high beam, then reduce glare: if you have a headlight leveling control, lower it; otherwise slow down and keep your lights on low beam. Do not retaliate by flashing high beams back - that blinds them and creates a hazard for both of you. Get the aim corrected as soon as practical; a misaimed headlight is a defect that should be fixed.
2. Visibility is limited and deer are common. What speed and scanning adjustments apply?
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The posted 90 km/h is a maximum for ideal conditions. At night with a grimy windshield, one misaimed light, and deer risk, you should reduce speed so you can stop within the distance your headlights actually illuminate. Clean the windshield at the first opportunity. Scan the road edges and ditches, not just the center, and watch for the reflective eye-shine and movement of animals. Use high beams when there is no oncoming or leading traffic to extend your sight distance, and drop to low beam promptly when traffic appears.
3. A deer appears at the edge of your headlights. What is the safest response?
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Brake firmly and steer straight if you can; swerving at highway speed risks a rollover or a head-on with oncoming traffic, which is often worse than a deer strike. Deer often move in groups, so after one crosses, slow further and watch for others. If a collision is unavoidable, brake hard and keep control rather than leaving the road.