Path: utzoo!mnetor!motto!ecijmm!jmm From: jmm@ecijmm.UUCP Newsgroups: ont.general Subject: Re: Highway Driving Rules Message-ID: <277@ecijmm.UUCP> Date: 6 May 89 03:35:39 GMT References: <89Apr26.134028edt.9320@ois.db.toronto.edu> <440@bnr-fos.UUCP> <9523@watcgl.waterloo.edu> Reply-To: jmm@ecijmm.UUCP (John Macdonald) Distribution: ont Organization: R. H. Lathwell Associates, Elegant Communications, Inc. Lines: 95 In article <9523@watcgl.waterloo.edu> kim@watsup.waterloo.edu (Kim Nguyen) writes: >In article <440@bnr-fos.UUCP> schow@bnr-public.UUCP (Stanley Chow) writes: >>The research that I have seen tend to say that it is not the absolute speed, but >>the relative speed difference that causes accidents. It is also said that the >>"slow drivers" cause more accidents for the "fast drivers" than the other way >>around. >> >>To summarise, low speed limit does not reduce accidents. Even it does, people >>should be allowed to *choose* to live dangerously. > >It inspires fear in me to see educated, intelligent people >advocating that "SLOW" drivers are the problem on highways. Pardon >me, but isn't it the drivers who disregard the law, common sense, and >civility who endanger the lives of law abiding (well, relatively >speaking, since we ARE talking about speeding :-), courteous drivers? > >If I am doing 120 on the 401 and some nutcase comes screaming up >behind me, weaving in and out of the lanes and slams his brakes on >right behind me, which one of us is the dangerous one? >... An incompetent nutcase is dangerous regardless of whether he drives fast, average, or slow. They come in all forms and are capable of disregarding the law, common sense, and civility at whatever speed they prefer to drive. Similarily, courteous, competent, sensible drivers come in the entire range of preferred speeds. The existance of the (highly visible) fast nutcase class of driver does in no way prove that *all* fast drivers are endangering the lives of the average speed drivers on the road. It seems clear to me that a slow driver usually causes more endangering than a fast driver. Consider: Assume a multi-lane divided highway with a moderate traffic load (i.e. most cars are separated by more than the minimum safe following distance). Assume that there is an large cluster of traffic which is travelling at approximately the same speed (i.e. within a 15 kph range - sufficient that there is some relative motion between these cars). Put yourself as an observer in a helicopter that is exactly pacing the cluster of cars - it is going the same speed. Watch a competent fast driver pass through the cluster. He changes lanes where neccessary to pass, slows down when approaching a clump that he cannot pass, joins the lane that is going fastest, and then speeds back up again when he has gotten clear of the clump. Another car in the cluster might be affected by the fast car if it catches up to a clump just after the fast car has passed it and ends up one car further back in the queue of cars moving by the clump. Otherwise, the fast car does not interact with the other cars. Now, watch the cluster as it passes a slow car. From the helicopter, this looks very much as if the slow car is driving backwards through the cluster, never changing lanes, never adjusting speed to ease his passage through the cluster. The cars in the cluster must arrange to get out of the way of this backward progress. Whenever he backs through a clump, there is not room for all of the clump in the other lanes, so the clump gets dragged backwards for a while, too, until it eventually does get past the slow car. So who is the greater hazard? The fast driver (assuming he is competent and not one of the nutcases described above), assumes the responsibility for ensuring that the difference in speed does not endanger the other cars on the road, which is why he slows to the average speed when it would otherwise be endangering. The slow driver forces the average drivers to collectively (and simultaneously) assume the responsibility for ensuring that the difference in speed does not endanger any of the other cars on the road. While many of the average speed drivers will be competent, there may be some who chose not to be high speed drivers because they feel competent to accept the responsibility for the difference in speed - these drivers are nonetheless getting such a responsibility forced upon them by the slow driver (of course, they are being forced to accept the difference only between themselves and one car, rather than between themselves and many cars, so it is not as bad as the position that they chose to avoid - except that when a clump approaches the slow car, there can quite suddenly be a large number of cars that have reduced speed considerably). In programming terms I consider the danger caused by the fast driver to correspond to a medium scale single program for which a reasonable proof of correctness has been made, while the danger caused by the average cars working their way around the slow car to correspond to a group of small scale but parallel programs each of which has a expectation of correctness, but no proof individually, and certainly no attempt to verify the interaction protocol has been made. -- John Macdonald