Explanation

"You need to understand how your headlights are designed to operate. The main beam is aimed far ahead and to the left, while the dipped beam is aimed a short distance ahead and to the left. On the road, this means that on left-hand bends your headlights are aimed directly at the approaching driver, so you need to dip early to avoid dazzling them. Similarly, if you stop on the offside at night, even your dipped beam will dazzle oncoming drivers, as it's now aimed directly at them; using parking lights will avoid any dazzle."