Aim to get the alignment of your headlights right

After 20 years of full-time traffic policing, you accumulate many memories.

I was reminded of one on the weekend when a small pickup truck passed me and I could see the bright patch from the right low beam headlight shining on the pavement about three meters in front of the vehicle.

The memory concerns a driver who thought headlight aim was unimportant.

I stopped that driver in much the same circumstances and issued a repair order for his vehicle. He brought the order back to the detachment showing the repair was carried out, but it was inside a card offering to buy me coffee so I could sit down, relax and hopefully not take the issue so seriously.

According to lighting expert Daniel Stern, lamp aim is by far the main thing that determines how well you can or can't see at night.

“It’s even more important than the output and beam pattern of the headlamps themselves,” he says.

If you don't worry about it, your vehicle may never have its headlights properly aimed. Canada's Motor Vehicle Safety Act does not require vehicle manufacturers to aim them before delivery to a customer. If you are purchasing a new vehicle, ask the dealer if the pre-delivery inspection includes checking if the headlight aim is accurate.

If your headlight beams are set too low, your ability to see at a distance is reduced. Set them too high and you can see further down the road but illumination of the pavement for vehicle guidance is affected.

Misaligned headlights can prevent oncoming drivers from seeing properly, possibly with severe consequences.

Oddly enough, a driver with misaligned headlights is more susceptible to glare from oncoming vehicles. The difference between light levels of oncoming lamps and the visual task area while driving at night is smaller when your headlights are properly aimed than when they are not. Your eyes see the latter situation as one with more glare.

If you are going to have a repair or body shop adjust your headlights, make sure it will uses an optical beam-aiming instrument. Here's an example of instructions for using a headlight-aiming instrument.

Doing it yourself is possible, but definitely not the best choice. There are detailed headlight aiming instructions about how to do the job on Daniel Stern's site. Be prepared to spend a significant amount of time to accomplish this.

Accuracy in adjustment is critical. If your headlights are improperly aimed by just half a degree, the amount of usable light projected even 23 metres (75 feet) ahead could be compromised and potentially useless.

So, sorry sir, I still think headlight aim is something to be taken seriously.

This article is written by or on behalf of an outsourced columnist and does not necessarily reflect the views of Castanet.