Gyratory Traffic Regulation. A NOVEL AND PRACTICAL SUGGESTION FOR DEALING WITH TRAFFIC AT BUSY CENTRES.

Progress, Volume III, Issue 7, 1 May 1908, Page 228

Gyratory Traffic Regulation. A NOVEL AND PRACTICAL SUGGESTION FOR DEALING WITH TRAFFIC AT BUSY CENTRES.

Some practical suggestions for the improved control of vehicular traffic at important street junctions w ere presented by Mr. W. Noble Twelvetrees, M.l.Mech.E., A.M.1.E.E., M.R.5.1., in his recent presidential address to the Civil and Mechanical Engineers' Society, at the Caxton Hall, Westminster. The maximum relief promised by the author's proposals could be obtained immediately in the more populous districts of London. The author stated that the greatest hindrance to vehicular traffic was that due to the compulsory stoppages necessary for permitting the passage of vehicles along intersecting routes, and to the blockages caused by drivers who endeavoured to cross comparatively open spaces along the shortest possible lines.

The intermittent stoppage of traffic at street junctions \\a , performed with admirable tact by the police. The duty of regulation \^as comparatively easy at points where not more than four thoroughfares converged, but less easy -where the number of converging streets exceeded four. To illustrate the system of gyratory traffic movement, he took the case of a junction such as that shown in Fig. I—where1 — where four streets converge upon an area sufficient to permit continuous locomotion. To avoid unnecessary complication, only one line of traffic in each direction was considered in each street, and the drivers of the vehicles were assumed to take the shortest cut to aoy chosen destination. The resulting sixteen points of conflict led to hopeless confusion ; the only lines free from intersections were those along the outside. A httle reflection would show that, if vehicles were prevented from penetrating into the central area, where conflict is so pronounced, and were compelled to follow a circular line, there could be no points of intersection. On the contrary, there would be a gyratory procession, receiving and distributing traffic along tangential curves at each of the four branches.

Fig. 2 shows the same hypothetical junction with gyratory traffic regulation absolutely obviating all points of conflict, and reducing the number of converging and diverging lines from 24 to 16. At the centre of the junction is a circular refuge, and at the mouth of each street a refuge, whose sides should be curved sufficiently to act as a training wall, guiding the flow of traffic in the required directions Gyratory traffic regulation was first proposed by Mr. Holroyd Smith, M.I Mech E; , M.I EMJ., who, some ten years ago, brought the idea before the London^County Council. Within the last eighteen months the notion has been advocated by M. Eugene Henarl, a Parisian architect, by Mr. W. H. Booth, A.M.Am.Soc, C.E.,

of Westminster, in a letter to the Times, and by Mr. Schroder, of Berlin, in a paper read before the " Verein fur Eisenbahnkunde." The author admitted that a certain amount of intersection must necessarily result from the establishment of concentric circles of gyratory movement But he thought that the difficulty was more apparent than real, and that any slight drawbacks that might attend the adoption of the gyratory system would certainly be more than counter-balanced by the avoidance of confusion, stoppages, and delays ; by the additional safety assured to foot passengers, for whom subways should be provided , and by the far smaller number of police officers required for the purposes of regulation In London there were several spacious junctions where the gyratory system could be applied very easily.

One point where the tiaffic congregated in peculiarly antagonistic fashion was the five-branch junction at the Oxford street end of Tottenham court road As represented m Fig 3, this junction would cause the formation of no fewer than 4o points of conflict, even for a single stream of vehicle-, in each direction, if the intermittent stoppage system were not applied by the police To show how easily matters might be improved, he gave a revised plan of the junction (see Fig -I)]

where the only alteration to property was the suggested easing of the sharp corner at the eastern side of Tottenham court road Then by the aid of a central plateau and the usual blanch refuges, the gyratory system of regulation could at once evolve order out of chaos It was not really essential that any of the buildings around tins junction should be touched, and the work of regeneration could be undertaken by the Commissioner of Police, after construction of the necessary retuges by the local authorities The fi\e additional curves on Fig. 4 show how a vehicle could pass from one street, to the next one on the left, without joining the main stream of traffic. He pointed out that it would be easy to show how other equally desirable improvements might be effected at numerous tramway junctions around the central districts of the Metropolis The address covered many examples of the gyratory system of traffic control, but space will not allow ot more examples being given here The author remarked tnat the object of his address was to point out various places where the system could be adopted tentatively, m order that its advantages might be demonstrated at little cost.