DRIVING ON THE BRAKES.

King Country Chronicle, Volume XXXII, Issue 4716, 14 November 1938, Page 3

DRIVING ON THE BRAKES.

ENORMOUS ENERGY REQUIRED IS OVERLOOKED. So many instances have been noted lately of what amounts to fierce braking that it is worth while, or is it, to draw the attention of drivers who use their brakes in that way to computations by experts whose job it is to study braking. Of course, there are times when an emergency crops up and when the driver has to apply every degree of braking which he can command, but allusion is made here to those drivers, prodigal of energy and running costs, who make most of their stops emergency ones, even when trailing a tram.

How often have you seen drivers using fairly high speeds, or at least unnecessary speed, to catch up with a tram slowing down for a wellmarked tram stop? The speed is maintained until close to the tram and then the brakes are applied in a quick stop. How often have you reduced your speed behind the speeding car or even coasted smoothly up behind car and tram at a stopping place? Sometimes, too, by the use of judgment, you are able to regulate your speed that, by the time you reach the halting tram, it has moved off again, and the use of your brakes or gears has been obviated. That is sensible, economical driving. But to return to figures which should be interesting to those who do not know the enormous stresses which they place on their braking systems: to those who expect minor miracles in the matter of stopping. Behind the smooth deceleration of the modern braking system there is enormous energy which is little understood, if at all, by those drivers who “drive on the brakes.” Such drivers would probably rely more on the engine to retard the speed of their vehicles if they were aware of the energy required to halt a swiftly moving motor vehicle. For instance, computations by experts show that a motor-vehicle weighing with load in the l’egion of 31cwt. when being braked from 10 m.p.h. to stop in 4ift develops 44 h.p. while stopping. From 20 m.p.h. to stop in 18ft calls for 90 h.p.; from 30 m.p.h. to stop in 40ft calls for 140 h.p.; from 40 m.p.h. to stop in 71ft calls for 188 h.p.; from 50 m.p.h. to stop in 111 ft 236 h.p. is developed, and at 69 m.p.h., to stop in 160 ft, calls for 280 h.p., which is equivalent to lifting the vehicle to a height of 120 ft in 3.6 seconds. Consideration of these figures should serve to bring home to motorists the terrific work they put on the brakes of their vehicles by undue and harsh braking, and why an occasional checking up of the braking system is advisable. And, by the way, if you are accustomed to driving on the brakes, don’t travel with your wheels tracking on tram lines. Your brakes will lock the wheels, but they will not prevent skids along tram lines that are wet. Why not slow down and make economical and safe use of your brakes?