Last week's column on driving lights led to a number of requests to write a follow up column on fog lights. Many readers suspected that the lights being asked about in that column were fog lights and not driving lights. I'm happy to oblige.
First, let's be sure we are all on the same page. Fog lamps are identified by the SAE F marking on the lens, or a B above the circle with the E in it on European lamps. In B.C. you are allowed two fog lamps that emit either white or amber light. They must be mounted on the front of the vehicle, below the headlamps, but not more than 30 cm below. When you switch them on, the parking lamps, tail lamps, licence plate lamp and, if required, clearance lamps must also illuminate.
Fog lamps may be used in place of headlamps if atmospheric conditions make the use of headlamps disadvantageous. Otherwise, fog lamps may be used at any time of the day or night and in fact are used as the daytime running lamps on some vehicles.
As with driving lamps, fog lamp aim is measured at a distance of 7.62 m from the lamp.
If the beam is symmetric, aim is measured at the center of the top edge of the high intensity area. They must be 100 mm below horizontal with an upper error of no more than horizontal. Lateral aim is straight ahead, but must be no more than 150 mm either side of vertical.
If the beam is asymmetric, aim is measured at the left of the top edge. They must be 60 mm above vertical with an error of no more than 175 mm above to 50 mm below horizontal. They must also be aimed straight ahead but must be no more than 100 mm either side of vertical.