Preventing being dazzled on the road

Keep your eyes to the left to avoid being blinded by the headlights of an oncoming vehicle.

Keeping your eyes to the left means you're not looking directly at the light and it will enable you to see the edge of the road more clearly. Your vehicle's headlights point slightly left of the central longitudinal axis of your vehicle to help avoid you inadvertently blinding other drivers.

You can be temporarily blinded by another driver's headlights if:

• The driver is towing a trailer or carrying a heavy load in the rear of the car and hasn't adjusted their headlights to compensate for this (this is because if the rear of the car is lower than usual the headlights will point further up)
• A motorbike is carrying a pillion passenger and the extra weight on the back causes the main headlight beam to shine higher - motorbikes usually have an adjustment for this
• The angle of a corner you are approaching means that you are in the direct beam of the headlights
• A crest or series of crests or bumps lifts the front of the approaching vehicle slightly
• The driver has forgotten to dip their headlights
• A driver with adjustable suspension has adjusted the rear suspension lower and not compensated for it.

If you are blinded then slow down and keep your eyes to the left. Once the blinding light has passed it will take a few moments for your eyes to adjust back to normal again, during which time you'll have reduced visibility which might include seeing coloured spots, or having less definition in what you are seeing.

Adjusting a car's headlights

If your car is new it will almost certainly have self-levelling headlights. If your car is 10 or more years old it might have a small dial, usually not positioned so you can adjust it while driving, which moves the lights' beams up and down. If you drive a really old car, then it'll be a manual adjustment.

Adjusting a motorcycle's headlights

You'll need your motorcycle's manual to find out where the adjustment screws or knobs are. Some are very easy to access while others are hidden away and need a long screwdriver. It's easier to adjust the lights at dusk or night but you'll want to find the adjuster screws in daylight.

Before you adjust the headlight, the bike should have 3/4 of a tank of fuel, the tyres properly inflated and a rider sitting on it. The bike must be upright and you'll need to be facing a wall on level ground, perpendicular to it, around 6 metres away. Measure the lamp height using a tape measure. Then on the wall measure the same height and mark it. 

Using a spirit level mark a line across the wall with some masking tape or chalk. Then draw another line two inches/5cm lower. The top line is your high beam reference point and the bottom line is your low beam reference point.

With your bike around 6m away the beams should line up with each piece of tape or chalk mark. If not, adjust them according to your service manual. The beams should be perfectly centred and not fuzzy.

There are usually two or more exposed screws