7.2.3. ATC is primarily a traffic management tool aimed at all traffic. Bus priority may be included in ATC systems depending on the system. For example, the UK considers three types of bus priority in ATC[22]:
a) Passive priority: within fixed time, plan-by-time-of-day systems, bus stops and dwell times can be input into the programs used to calculate signal timings using BUSTRANSYT. Signals timings are calculated, and weighted, to recognise the differences between bus movements and other traffic. For responsive ATC systems, bus links can be similarly weighted. The benefits of passive bus priority are limited – maybe 5% reduction in bus journey times. Furthermore, in developing cities, where there are very high bus flows and unpredictable bus stop times, the approach may have small value;
b) Active priority: individual buses are detected on traffic signal approaches and signal timings modified to allow buses priority; this is more straightforward for fixed time, plan-by-time-of-day systems but is feasible for responsive ATC systems. Again, with high bus volumes in developing cities, the approach may not be straightforward; and
c) Bus tracking: requires a system to track all buses at all times on-street. The ATC system has to have an interface with the bus tracking system such that the arrival times of buses at junctions can be predicted and the signals adjusted accordingly. The system requires all buses to participate in the tracking system which, with the large numbers of buses, companies, types of vehicle in some developing cities, would be problematic.
7.2.4. Thus, while there are measures which may be included in ATC systems to assist buses,
those measures are complex, relatively costly add-ons to basic ATC, some are not yet fully developed and they may not be appropriate for the developing city context. In general, ATC is most likely to benefit all traffic, which will include, but not concentrate on, buses and is probably essential for a well managed city. Poverty impacts are likely to be positive but in developing cities, poverty impacts (together with the most efficient use of road space) are best achieved by physical bus priority lanes and busways.
7.3.1. Buses are (or perhaps will become, as in China or some Indian cities currently with little formal public transport system) the backbone of the transport system for many cities, and will remain so, for the foreseeable future. Buses are important, inter alia [23], to the poor and positive reallocation of road space from cars to buses will assist operations and
will capitalise on the efficiency of buses in using that road space. Experience in developing cities varies greatly world-wide; for example:
a) In Latin America, there are many cities where road space has been reallocated to buses to provide bus priority and bus lanes on either on a system-wide basis or a scheme-by-scheme basis. Bus lanes and busways exist in probably 100’s of cities with notable systems or extents in Curitiba, Porto Alegre, Sao Paulo, Bogota, Lima,
Quito, Santiago, Mexico City, Leon, many other others;
b) In Asia, there are few developing cities which have allocated extensive road space to bus priority and busways. As far as is known, these include only Bangkok, Manila, Madras and Kuala Lumpur. It is surprising that there are so few bus lanes in many major and medium sized cities that operate conventional bus systems. However, in at least the three former cities, enforcement of with-flow bus lanes (as opposed to the contra flow bus lanes which constitute most of the Bangkok lanes) remains problematic.. It is noted that in Chinese cities, a limited number of segregated busways are proposed under Bank projects but indications are that these will not be easy to implement nor to gain political acceptance;
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