ROAD LIGHTING

Evening Post, Volume CXXIV, Issue 57, 4 September 1937, Page 28

ROAD LIGHTING

BETTER IS POSSIBLE

A MATTER OF ARRANGEMENT

Despite the wonderful improvements that have been accomplished in headlights the main problems in night driving remain, inability to see any great distance ahead, inability to see the road surrdundngs, inability frequently to see objects on the road and the continued annoyance and danger of dazzle and glare.

Various countries react differently to these problems. The first to seriously consider the dazzle problem was Ame-

Rica and probably America remains the most stringent in her objections to it. The headlights of American cars, taken as a-whole, are weaker than those providedjMi British and Continental cars, arid it was America that first brought in and insisted on a low level of beam. These things, however, are mere palliatives. To a certain extent they avoid dazzle and glare but they do not cure it. 'And in avoiding it they to a large extent introduce the trouble of insufficient' vision.

The road lighting problem will probably never be solved from the car. It; is to road lighting that resort must eventually be had, and road surfaces that throw into contrast the objects upon it. The chief difficulty-about headlights •is their limited extent of clear vision. The beams seem to-penetrate far ahead but in reality their effectiveness diminishes rapidly with every foot. They advance, and well within range of the car speed they are weak and ineffective. They are a trial also to the eyes. Close at hand the retina closes; as the distance grows it opens and tries to accommodate itself; to the feeble light that offers. It is hard work on the eyes, for the light is never the same; the eyes try now to see close, now well away, and ever and anon come the beams of traffic out of the distance ahead rapidly growing with a fierce and blinding glare that renders them useless, and leaves them paralysed after it has gone. The light variations are too violent and too speedy for the physical structure of the human eye, which requires time to accommodate itself to varying conditions. Take the simple instance of the Wellington traffic tunnels. A person on foot entering the big one through to Kilbirnie is hardly conscious of . any change. Out of broad daylight one walks steadily forward into what seems la well-lit interior. At a speed of from three?to four miles an hour the eye is hardly conscious of any change. But when a car plunges into the tunnel it is like the fall of a tropical night, despite' the lighting. How blinding it is was brought^ forcibly? home, to the writer a short time ago when he took a canary through. Th»; preature went to roost. ■ A few weeks later, when it was being taken back home, It went to roost again.

'.From the tunnel'in^o the broad light of dEiy, there is again a sharp demand on the;physical structure of the'Jeye, a period- during which it is busily; re- ■ adjusting itself, to the' change. « That kind of ■■adiUstmerit goes' on continually in night1 driving., ;'' '■ ; ',-h'.':. '•. Modern lighting has done much to bririg nearer the time when busy roadways will be lit apart from the car. There is no ne^d,' however, to wait till the perfect lariip comes along.- The old' lamps can be used to give quite good lighting if they are used in the right way. •If one looks at the street lamps it is quickly apparent that a great proportion of the available ■ light is thrown away where it is not needed. The customary practice >is to suspend ; the bulbs in round shades which spread the light in a circle, the result being that only portion of the arc falls on the roadway, all the rest, which is considerably more than half, being cast around in useless places. There is no need of; municipal lighting for front . gardens; it should be possible even with lights suspended over footpaths to be so directed that most of the light, if not all, is directed to.footpath and road. - Better still, all lights could be suspended over the centres of the streets and, not along the footpaths. The same number of bulbs and shades would give twice the number in a single 'straight line, and there would be ample coverage in the circle of beams to reach the footpaths and light them -effectively both for pedestrian and motorist. In busy streets it should not be beyond economic reach to have lights frequent enough to give pronounced overlapping of the circles of light and achieve something approaching a uniform. lighting in that way. Floodlights have the same weakness that headlights have; they seem very brilliant but actually they create violent contrasts, due to the speed at which they lose power as they pierce the distance. , Lights should never be judged for effectiveness from their effect to a person standing still or moving slowly. They should be judged from their effectiveness on eyes that are fast moving forward, which, with most floodlighting as we at present know it, is only a series of progressions from-brilliant patch .to dull and; dull to brilliance, a grass-hopper , kind of stunt imposed on eyes that have demands enough upon them without artificial gymnastics of this kind. The aim in street lighting should be

not brilliance in a light but.a diffused glow uniform in its result over the whole of the pavement. That is tha ideal. Of course it cannot be fully attained; even daylight does not attain it, but something more approaching to it ought to be more attainable from appliances already at hand than has been the case hitherto.