Traffic signal

“ When confronted with a situation in which motor vehicles are standing or running slowly in a queue at the section or junction of a road where the lanes are decreased, or at a road crossing where there are no traffic signal lights, traffic signs or traffic line markings or direction of traffic police, the motor vehicles shall take turns to pass in order. ”

“ Traffic light signals designed primarily for controlling the movement of vehicular traffic also contribute to the safety of the pedestrian in providing opportunities for crossing the carriageway when vehicular traffic is held up. In designing traffic light signal installations the needs of pedestrian traffic should be fully considered and such provision for that traffic as is practicable should be made. ”

“ We believe that the visibility of traffic signals would be further enhanced by contrast if the signal heads were painted entirely black, instead of being banded black and white as they are at present. As it is important that traffic signal installations should be conspicuous both to drivers and pedestrians we consider that the present practice of having black and white bands on the supporting posts should be continued. ”

“ Special signal installations are sometimes provided away from road junctions to facilitate crossing of the carriageway by pedestrians at points where both vehicular and pedestrian traffic are heavy. The modern types of signals are actuated by vehicle detectors placed in the carriageway and by push buttons or similar devices operated by the pedestrians desiring to cross. ”

“ At most crossings, however, pedestrians are at present expected to judge for themselves when it is safe to cross by keeping their eye on the traffic. At the simpler junctions pedestrians are usually able to see at least one signal appropriate to each traffic phase to help them in judging the traffic situation. But where complex methods of control are employed, signals can be confusing or misleading and it is safer to judge mainly by watching the traffic. ”

“ Where one-way systems have been introduced signal-heads facing the direction in which traffic no longer flows should be retained and their lenses masked to show only a cross so that pedestrians are warned before traffic starts to move again. ”

“ It should be the aim to provide room for at least one vehicle turning into the minor road to wait at the crossing without obstructing traffic on the major road. More vehicles should be accommodated if there are large numbers turning. If signalled pedestrian crossings are sited too close to junctions, drivers might mistake a vehicular green signal for a priority signal over traffic on the major road.
15.21 Where part of a lay-by lies within the controlled area, the zig-zag markings should be laid along the edge of the main carriageway. ”

“ TRAFFIC SIGNAL STOP LINE
3.7 The marking (diagram 1001) consists of a single continuous line 200 mm or 300 mm in width and indicates the position beyond which a driver must not proceed when required to stop by light signals. The 200 mm width is generally for use in urban areas. The 300 mm width should be used in rural areas, or where the 85th percentile speed exceeds 35 mph. The greater width may also be used in urban areas at difficult locations, or where heavy traffic results in rapid erosion of the marking. ”

“ On installations at junctions where pedestrian traffic is regular but not exceptionally heavy, we consider it desirable that additional three-light signals (showing the same signal as the appropriate primary signal) should be provided so that a pedestrian about to cross the road at the junction can see at least one signal immediately facing him. ”

“ In our view a great deal more could be done by the use of carriageway markings to increase safety at junctions not controlled by traffic signals or police and to remove doubt from the minds of drivers and consequently to make such junctions safer. ”

“ Units along a highway that regulate or advise the vehicle operators are broadly known as traffic control devices. Presently they consist of traffic signals, signs, pavement markings and other markers or delineations along the roadway. The earliest forms were milestones and notched trees. With the advent of the automobile, signing and markings became prevalent in the early 1900’s on principal highways in and around the larger cities. Most of these early devices were developed by innovative people based primarily on their imagination and ingenuity. ”

“ Without prejudice to the obligation to obey an instruction to stop given by a light signal or a sound signal, no road-user shall enter a level-crossing at which the gates or half-gates are across the road or in process of being placed across the road, or at which the half-gates are in process of being raised ”

“ Alternate one-way working past an obstruction should be controlled by traffic signals where traffic is dense or at extended obstructions; by manually operated Stop and Go signs where traffic is not dense and obstructions are small and of short duration; and, where the above means are not justified, by signs indicating the direction in which traffic has priority. ”

“ Where a signal phase permits opposing right turns but no ahead movements from the right turn lanes, and there are no opposing dedicated lanes, use of the arrows to indicate that vehicles should pass near side to near side will help prevent conflict. If the number of right-turning vehicles is high, it would be of benefit to provide a dedicated right turn lane even if a separate signal stage is not provided. ”

“ It remains to consider the problems of how best to help pedestrians at traffic signals. This help will normally be at the expense of vehicle flow, as is the case with the all-red phase when introduced for pedestrian benefit at junctions, and a decision on whether to introduce it will depend upon the number of pedestrians to be catered for and the vehicle flow. ”

“ If the crossing is not equipped with such lights, but vehicular traffic is regulated by traffic light signals or by an authorized official, pedestrians shall not step onto the carriageway while the traffic light signal or the signal given by the authorized official indicates that vehicles may proceed along it ”

“ Experience abroad suggests that these lane control signals should be repeated at intervals of not more than 300 yards and that they should not be placed where they can be confused with signals controlling intersections.
249. There is a serious danger that traffic signals in urban areas may fail to be seen because they become confused with the background lights of shops and advertisements. Powers already exist to prevent such lights being placed where they conflict seriously with the efficiency of traffic signals. ”

“ In practice we do not think that the junction warning signs which we recommend will be widely required. On major roads they will only be needed on those rare occasions where there are no traffic signals and no map type advance direction sign and where drivers cannot see a side turning or the direction signs associated with it, for example, because of a bend or hump in the road. ”

“ Where there is a gap in the central reservation and traffic can turn right into the dual carriageway from the side road, "no entry" signs might be beneficial to deter drivers from turning into the wrong carriageway. Where the junction is controlled by traffic signals, the signs would usually not be necessary. ”

“ They do not affect the general principles formulated by the 1933 Committee, nor have they necessitated any major alterations in the layout and operation of the signals as viewed by the road user. From the latter aspect practice is now largely standardised and is familiar to the road user, and we see no reason to introduce any major changes. We desire, however, to emphasise that traffic signals should be installed only where it is not practicable by improved road layout (e.g. by grade separation or by roundabouts) to provide for the safe and uninterrupted flow of traffic. ”

“ Traffic control devices are the several elements provided on highways to advise, guide, warn, regulate or otherwise inform the vehicle drivers. The basic types of devices are signs, pavement markings, roadside delineators and traffic signals. The 1971 Manual on Uniform Traffic Control Devices was approved by the Federal Highway Administrator as the national standard for all highways open to public travel. ”

“ Both signs should be internally illuminated at all times. (At present the Turn Left (or Right) sign is only illuminated when the green signal is illuminated, but is legible at all times during daylight.)
(b) The signs should be placed beside the green lens, and on that side of the signal head appropriate to the wording on the sign (e.g. “Turn Left” on the left side of the signal and “No Right Turn” on the right side of the signal) provided that this can be done without rendering inadequate the clearance between the signals and traffic on the carriageway. ”

“ If visibility is such that a Stop line would be justified, the left turn should be brought under signal control. A left turn slip lane should be separated from the other lanes by a traffic island. If no provision is made for pedestrians, they are likely to have difficulty in crossing an unsignalled slip road in an otherwise signalled junction. ”

“ The detailed arrangements for marking roundabouts and signal controlled junctions are described in sections 8 and 9 respectively.
4.25 The number of marks recommended in table 4-3 is the minimum on each approach, although this is not always possible on minor roads. The number of marks should be extended wherever justified by road or traffic conditions; the marking can with benefit be extended to start at the location of the accompanying warning sign. Figure 4-5 indicates
a possible combination of signs and markings at a road junction. ”

“ At certain junctions where control is not exercised by traffic signals, police, or a Stop sign there will nevertheless be a need for a sign in addition to the new transverse carriageway marking which we advocate in paragraph 224. We therefore recommend for this purpose the sign at figure 8. Since avoidance of accidents will depend upon drivers obeying the sign we believe that it should be given a legal mandatory significance and the meaning of 'proceed so as not to cause inconvenience or danger to traffic on the major road'. ”

“ A traffic survey should be carried out to determine the extent of the problem, not only to assess the suitability of the junction for box marking but also to establish whether any alternative measures might be effective (e.g. re-timing or linking of traffic signals at adjacent junctions) . ”

“ A plate to diagram 573 (see section 18) is used where the signals are located along another road. When used on a dual carriageway road, the signs should be duplicated on the central reservation.
8.2 The sign may be used with all three-aspect type traffic signals, including Pelican, Toucan and Puffin crossings and portable traffic signals used at road works. It is not for use with wig-wag signals to diagram 3014, where diagram 563.1 or 773 should be used with the appropriate warning sign (see sections 17 and 21) . ”

“ They therefore include not only roadside signs, but traffic signals, carriageway markings, 'catseyes' and indications on street bollards.
There are four classes of roadside traffic signs, mandatory, prohibitory, warning and informatory. Prohibitory signs (e.g. No entry) give notice of a Statutory Order or Regulation and entail penalties if ignored. Penalties are also entailed if a mandatory sign (e.g. Keep left) is ignored . ”

“ At certain types of junctions where there is two-phase control, such as T junctions, staggered crossroads and junctions with one-way streets, we think that additional signals should more frequently be installed to ensure that pedestrians can see not only the signals controlling the traffic stream they are about to cross but also those for traffic flowing at right angles. ”

“ In the method of control known as the flexible progressive system the signals at a number of adjacent junctions can be co-ordinated in such a way that traffic may proceed at a uniform speed along the main thoroughfare without being held up at each successive intersection, while at the same time frequent opportunities are given for cross traffic to proceed. ”

“ But instances are rare indeed in which the congestion of through highways in cities has been attacked at its principal root—the frequent grade intersection of cross streets. Instead of eliminating this principal cause of traffic delay, city authorities have generally resorted to the installation of traffic lights for control of the intersecting traffic streams and the prevention of accidents, and this expedient measure has in some cases been so applied as to increase rather than reduce the obstruction of traffic. ”

“ With the exception of traffic signals and zebra crossing beacons, all posts, brackets and fittings used for the mounting of signs, as well as the backs of signs and any bracing, should be coloured grey. ”

“ In this country where the road pattern is so complicated, we think it would assist travellers in finding their way between important towns if a system of Primary routes other than motorways was established, the roads in which would be clearly distinguished by having directional signs of a particular colour. Moreover, we foresee that this distinction might eventually enable a code of improved driver conduct, aimed at improving traffic flow and safety, to be applied generally to these Primary routes. ”