The Birmingham age-herald., 1924-09-14
WHEN TO DIM
 HEAD LIGHTS
By BARNEY OLDFIELD

To dim or not to dim, or more accu- rately, when to dim the headlights is problem that few have been able to solve to their satisfaction. On the one hand, motorists accustomed to dimming whenever a car approaches, are nat urally incensed if the other fellow fails to reciprocate. And on the other, mo- tor1sts who prefer to pass approaching cars with headlights on full dislike to dim. The fact that dimming is popu- lar in some parts of the country and not in others, and that it is equally un- popular in other sections, proves that there is much to be said on both sides. Nor does the fact that some states have laws requiring dim headlights when passing another car affect the | discussion.
 Careful analysis of the problem shows that on well lighted roads and streets. if the majority of the motorists run with dim lights, the minority who pre- | fer bright lights should bow to the ma Jority, dimniing their lights as required, or preferably running solely with dim lights, since the assumption is that the l streets or roads are lighted and bright lights are therefore not necessary, On l such highways, if the mOtorist runs continuously with dim lights his eyes will soon become accommodated to the quantity of light Illuminating the road way, and adequate vision will be se- cured, whereas if the lights are only dimmed as required, his eyes, accus- toned to bright lights, will be inade- quate during the periods that his lights are reduced.
 If the road Is nos illuminated, safety demands that brighS lights be used even when passing another car, pro- vlded state or city law permits. This statement will be challenged by many but its correctness may readily be proved. Try passing cars with your 1 lights alternately dim and bright. Ton will discover that you can see the road | better with your lights bright and the other fellows lights bright, than YOU can with both pairs of lights dim. | There would be little question about this matter were it not for the fact that not all cars are equipped with adequate anti-glare lenses, and a few cars in use are not equipped with any antl-glare device. Anti-glare lenses should prevent the light beams from rising above the horizontal but some of the devices in use meet this condition OiiJ SAAShLyt pcllS lLtle or no better than clear glasses. In some cases. also, the lenses are adequate but the lights glare badly due to the fact that the bulbs are cue of focus or the lens glasses turned upside down or side ways.
 The first step therefore is to see that your own lamps do not glare ;; in other words, few rays of light should stray above the horizontal. See that your lens glasses really prevent glare, and if not, procure new ones. To determine whether your bulbs need focusing nlace your car 25 feet in front of a light cOlOred wall and note whether the spot of light is rather sharply marked off by a horizontal line approximately the same distance from the floor as the lamp bulbs. If not, adjust each bulb by moving it in or out until sharp line is secured. In come cases the bulb is held by friction and is moved by hand; in others, screw in the pack of the lamp housing is turned. IfJit is necessary to remove the lens cover l glasses in order to focus the bulbs, ad-