What can we do about traffic congestion?Posted: March 6, 2010
The Federal Government’s State of Australian Cities 2010 Report was released yesterday. It says the avoidable cost of traffic congestion in Australia’s capital cities was $9.4 billion in 2005 and is expected to rise to $20 billion by 2020.
What can we do in a city like Melbourne about congestion? There are four basic ways to address the issue:
- Increase road space
- Shift travellers to a less-congested mode
- Suppress demand for road space
- Manage the level of demand
The first approach involves building more road capacity e.g. new or widened freeways. However people seem to have an almost inexhaustible demand for travel, so as soon as a route gets faster due to added capacity, it pretty quickly fills up again until once more it becomes congested.
The second approach usually involves attempting to shift drivers out of their cars and onto public transport. Traffic congestion is positive for public transport because it undermines the cars speed advantage. The problem however is that any road space liberated by travellers shifting to public transport is soon filled up by other drivers as per point one above. Moreover the customary assumption that the alternative mode isn’t itself congested doesn’t always apply e.g. Melbourne’s currently overloaded train system.
The third approach is to suppress demand. This is what happens at present with traffic congestion – the road effectively becomes clogged and can’t carry any more cars. The key downside of congestion, however, is that it slows everyone down equally. High value trips – like say a job interview, a funeral, an important business meeting, a load of freight – are slowed as much as comparatively low value trips like driving teenagers to school or doing the daily shopping during peak hour.
The fourth way involves a number of measures but the key one is road pricing – requiring drivers to pay a charge (toll) for road space, with prices higher during peak periods. Drivers making high value trips at peak hour will be more inclined to pay for the privilege while those making low value trips will have an incentive to seek out alternatives, such as possibly not making the trip at all, scheduling it for an off peak period when the toll is lower, or shopping once a week rather than every second day. Some trips could even be taken by walking or public transport rather than by car.
Road pricing is the most sensible approach. The main disadvantages are the charge that it is inequitable and the reality that it would be difficult to implement politically – drivers get angry at having to pay for something that they’ve always regarded as free. I plan to deal with these issues in a future post.