Road congestion: the stark reality

This number of buses and trains must be added each year, not just as a one-time expansion of capacity. If these were added in one year and then nothing else done, the traffic would continue to worsen thereafter.

We conclude from this that major investment is needed in public transport just to keep pace with the growing demand for travel, as population grows, and that it is probably unlikely that government can find sufficient money to increase road capacity to accommodate most of the growth in car travel which will become increasingly congested.

Can congestion be reduced by building new roads? In modern times, it has become clear that this is impossible. When road capacity is added to reduce congestion, the congestion reductions are short-lived, because people travel more and further with the added capacity; congestion eventually returns to the same level as before, or becomes worse.

One reason for this is that road users do not pay the real costs of using the road, and so adding new road capacity is almost like giving people free tickets to travel - they will choose to travel more, and further. However, this is also not to say that more road capacity should not be built. We are talking here about building extra road capacity to try to reduce congestion. On the other hand, if we road-building just stops, then those additional 17,500 car trips in the morning peak per year will have to squeeze into the existing road space, which is already congested.

In Sydney, on average, trips by car are about 10-11km long. That means about 175,000 additional vehicle kilometres of travel must be accommodated in the system each year in the morning peak. On average, main roads and motorways can accommodate about 1,200 vehicles an hour per lane. If the morning peak lasts two hours, then an extra 73 lane kilometres are needed every year in each direction, just to accommodate growth.

The M2 motorway in Sydney is 20km long and has two lanes in each direction - 40 lane kilometres in each direction. The amount of new road space required to accommodate just population growth so that congestion gets no worse is equivalent to building about two new M2 motorways every year.

It should be clear that dealing with congestion is a major problem. Not only does it look as though it cannot be reduced, but it will be difficult to stop it getting progressively worse.

Can nothing be done about this?

There are some things we can do about it. One of the most obvious is to change the way in which those who use roads pay for using them. At the moment, we pay for roads through fuel taxes, vehicle registration, and some other taxes. However, apart from the fact that cars use more petrol in “stop and go” conditions than in free-flowing conditions, we don’t pay for the congestion we cause.

What we pay for road use at the moment is very insensitive to where and when we choose to drive, and does not represent the real costs imposed on others (through delay), on the environment (through noise, pollution, and so on), and through accidents. Many experts would describe fuel taxes as a blunt instrument for charging for road use.

Even with increasing petrol prices, cars are perceived as inexpensive, and we choose to drive where and when we wish. We are much more responsive and responsible in our choices when we are required to pay a sufficient amount to stop and think as to whether we really need to make that expenditure.

The car is really free at the point of use, because we don’t put our hands in our pockets to pay to use the car each time we want to go somewhere. If we did, we might think twice about whether or not we really had to use it. This is the principal behind road user charging.