Wednesday, October 13, 2010

Lights, no camera, and not much action

Inner Northern Busway (upside down)
BrizCommuter had to travel along the Inner Northern and South East Busways mid-afternoon. It took a highly unimpressive 15 minutes just to travel a few hundred metres from King George Square Station (pictured) to Cultural Centre. Why? The traffic lights at the exit from the Queen Street Bus Station were only letting two buses through per cycle from Queen Street Bus Station, and the lights were not on a particularly short cycle either. BrizCommuter is convinced the buses were usually faster when they were routed via congested North Quay. So much for progress! Can anyone explain why the traffic lights are set so as to limit the capacity of the busway? Surely buses should have priority over cars?

Whilst on the subject of backwards public transport, BrizCommuter has to get to work for 8am this Sunday. With a pathetic hourly train service, BrizCommuter would get to work either 50 minutes early, or 10 minutes late. Unfortunately the latter is not an option, and BrizCommuter values his sleep too much for the former! The bus service that runs past BrizCommuter's house does not even start until after 9am. It should be noted that at the same time on a Sunday morning in Perth, the trains run every 15 minutes, that's 4 times more frequently than in Brisbane! Do TransLink and QR realise that some people actually work on Sunday mornings?


  1. Brizcommuter, the busway is so frequent that often headways are below 90 seconds. A traffic light takes that long to go through a cycle.

    If buses were always given priority by the traffic light, the light would be stuck permanently on green for the bus, and no further movements would be possible at the intersection from any other direction.

    This is why those signals are not prioritised.

  2. The traffic lights were only letting through 2 buses from Queen Street Bus Station (QSBS) about every 2 minutes. That is a measly 60 buses/hour. The busway through Cultural Centre can handle over 170 buses/hour. Although not all buses run through QSBS, this is an inefficient use of public transport infrastructure, and was resulting in delays of more than 12 minutes to buses!

  3. Letting only two buses though on average, with a 1.5-minute wait for the next cycle, is utterly obscene. Surely that set could be programmed to a much faster cycle like the Melbourne St portal.

  4. 60 buses per hour is one bus per minute- about the same time that the traffic light takes to change.

    You can't give a bus traffic light priority if the buses arrive faster than a light can change. The buses must therefore queue.

    The Melbourne street portal is also highly unlikely to have any kind of signal priority either, for the same reason- there are too many buses arriving too quickly to give them all priority.

  5. They need to abolish the Cultural Centre-William St connection and reduce the number of sequences in the traffic light cycle. And what a stupid comment from "Anonymous"! Let's not have public transport at all.

  6. Simon, think about it.

    If you prioritise every bus so that each time a bus approached the traffic light it would turn green, each time the bus did that the light would stay on green for 60-90 seconds approximately, in which time the next bus would have arrived at the light, also triggering it and making it turn green.

    Now, if you have a bus arriving every 60 seconds, the light will be PERMANENTLY STUCK ON GREEN.
    Effectively, you will close the intersection and make it impossible for traffic flow in any other direction!

    This is why busways have their own dedicated lanes with very few traffic lights.

  7. The point is that letting through 2 buses every 2 minutes causes big bus delays. The traffic lights need to be able to be adjusted so as to prioritise bus traffic over car traffic within reason. This does not mean keep the busway lights green until their isn't a bus in sight, more of a case of if there are 5 buses waiting at the lights, give the busway a green light for 40 seconds instead of 20. Ultimately, busway capacity is not going to be maximised until the road junctions either side of the Victoria Bridge are grade-seperated.


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