17 OCTOBER 1925, Page 13

MOTORING NOTES

THE HEADLIGHT PROBLEM

tirarama has done more towards making the motorist disliked than the use of powerful headlights. The annoyance caused to drivers of carts, to cyclists and walkers is a very real one ; no one admits this more readily than the motorist. But the difficulty up to the present-has -been that no really satisfactory solution to the headlight dazzle .problem has been found, and the motorist has had no option but to use these powerful lights when driving On a dark night. The fact that modern roads are nearly always black necessitates the use of much more powerful lights than would be needed on white roads. I have urged for some years past that a partial solution of the problem would be to finish the road surface a light colour.

One has only to leave a main road when driving at night and pass to an untarred country lane to realize this. Many times, even on the darkest of dark nights, I have been able to switch- off the headlights when leaving a main road, the lights from the side lamps being ample for any ordinary purpose. The same thing is true when travelling along certain sections of some of our newly-constructed roads, which have been finished a light colour.

The glare from many headlights is greatly intensified because the lamps are improperly focused. The beam of light is in a wrong position, possibly shining right into the faces of on- coming drivers. The correct focusing of the lamps does a great deal to eliminate dazzle. The plan of switching-off the headlights when meeting another vehicle has its admitted dangers. Personally, I think the system a very bad one, and in this view I am supported by the Royal Automobile Club, and by Sir William Joynson-Hicks, who, at a demon- stration of anti-dazzling devices held a few days ago, said :-

" I do not believe in dipping or switching-off lamps, since the fact of cutting off headlights leads to grave risks of causing serious acci- dents to cyclists or pedestrians on the near side of the road while the driver is approaching another car."

From the moment the plan of switching-off was advocated many years ago I have fought against it, for it is extremely dangerous for the motorist to be plunged into darkness. The difficulty, too, has been increased owing to the facts that some motorists adopt the plan and others do not, and that when one motorist switches off his lights and the approaching driver does not respond, he immediately switches them on again, which is very confusing. It must be remembered in this connexion that the switches on many old cars are in an inac- cessible position, where the driver cannot reach them without stopping his car, while, again, many cars are still fitted with acetylene headlamps, and these cannot possibly be switched-off, Several excellent dimming devices have been introduced, which greatly reduce the glare, but these are not always very trustworthy, while with some the light is so much reduced that almost the same effect is obtained as by switching-off the lights altogether. Some British manufacturers are still following the American practice of fitting dimmers, but many firms are trying to evolve an improvement, so that the total volume of available light is not diminished. Dipping headlights have also been brought to a high state of perfection, especially those of the Barker system ; but they require to be used carefully, so as not to darken too much of the roadway. Of the mech- anical devices which have so far been introduced this system of dipping headlights is certainly the best.

My own car has very powerful lights, as I do a great deal of night driving, and a little while ago I fitted a pair of Parabolite lenses, which have proved really excellent. The surface of the lens is divided into three sections. In the top section there is a number of concentric semi-circular prisms, the bases of which face towards the centre of the lens. In the bottom section there is a number of semi-circular prisms with their bases facing away from the centre of the lens. These two sections of semi-circular prisms are separated by a wide horizontal prism, the base of which faces downwards. Ap- proaching traffic faces no glare, but only two softly glowing circles of light.

The simplest solution of the problem of headlight dazzle would seem to be the substitution of tinted translucent bulbs for the colourless transparent ones. The new bulbs which

have been.produced-.-they were shown at a demonstration last week—are admittedly not perfect, but they retain about four-fifths of the ordinary bulb's efficiency, and eliminate , glare to a wonderful degree. Last winter I experimented a • good deal with various kinds of bulbs, and I found that when I coat...1 an ordinary bulb with pale blue celluloid varnish the light was not nearly so dazzling, and as it was more efficient a. less powerful lamp was necessary. The light was also more penetrating in fog. What I tried to do was to imitate the " daylight " bulbs used in the operating theatres of hospitals- The varnish I used was made of celluloid dissolved in amyl acetate coloured with methylene blue. It is better to dip the bulb than to paint it.

E. T. BROWN.