Annex 6 Limitation of Conventional Bus Priority Lanes: Case Studies

HCBRT systems have sometimes been described as ‘closed’ systems – as the passengers, once within the system area/units, can go anywhere within the network. ‘Open’ systems simply offer road space – in the form of traditional bus lanes – to existing bus routes, in order that they can escape some of the general traffic congestion. The ‘open’ system works best under a relatively low volume of bus traffic.

Busways offer uncongested space, but do not solve the problems at bus-stops. Many experiences with high-capacity busways in Latin America and China have now shown that the operating problems of ‘open’ systems cannot be resolved without integration. Typical problems are:

  • Confused boarding and alighting.
  • Excess number of units operating on the corridor.
  • Vehicle delays at intersections. Only a few units can pass the traffic signal per cycle. This is due to the waiting times of all units to get to the loading area and finish loading/unloading during the green time.
  • Queues at Signals. If intermediate stops are located close to intersections – often a necessity for passengers to cross the road – long bus queues can form on the approach lanes, blocking access of units to the loading areas.
  • Too Many Public Transport Routes on the Busway. Average speeds on the busway are determined by the slowest unit. This is often no more than 10–12 kph.

Several cities have learnt this lesson and are in the process of upgrading their busways into integrated HCBRT. Kunming is moving from the peak congested BOL to a modern form of HCBRT in order to increase capacity. The same process is being followed in Brazil in Sao Paulo and Porto Alegre, where the bus companies are implementing the key elements of HCBRT on their busways in an effort to increase operating speeds. In Sao Paulo, this is expected to raise commercial running speed from 14kph to closer to 20kph in the peak. This is equivalent to almost a fifty per cent increase in the bus fleet – without the extra cost to operators or passengers. The case of Seoul also deserves special attention, as the BOL in Seoul were modified after severe traffic jams on the median bus lanes were reported due to heavy traffic clogging. The volume of buses allowed to use the BOLs was decreased in an effort to improve running speeds.

The following sections examine capacity of BOLs in each of the case study cities.

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