FOR MANY years I caught buses at peak hour on Northbourne Avenue. To amuse myself as I waited I would count the number of cars with only one occupant that passed me, or the number of cyclists, or pedestrians who crossed the avenue at the pedestrian crossing.

It was never a scientific study, but the count was often surprising. At the lights, cars stretched back what appeared to be a long way, blocking all three lanes. But often there were only about 20 people held up by this - three lanes of six or seven cars and a few trucks.

Crossing the road when they got the go-ahead there were often more people.

Commuters at the bus stop could spot their bus caught in the traffic well before it arrived. And when it came the bus would be caught again, sometimes just a few cars short of a stop. When the traffic started to move, it would have to stop again to pick up the passengers.

It seemed obvious to all that the wide open space in the middle of Northbourne Avenue should be used for the purpose of getting commuters into town a little faster. Not that any of us wanted to see the trees cut down. Only the ACT Department of Environment (or whichever authority ''manages'' the trees) is keen on that.

Now the ACT government has released a plan for the corridor for all to consider. The options are a Bus Rapid Transit or a Light Rapid Transit system.

One look at the cost and the decision is easy. The bus option is priced at $300-$360 million, while the light rail is more than double that at $700-$860 million. Even if the light rail cost is inflated, as its proponents claim, there can be no question that this option would be significantly more expensive than the bus option.

It is estimated that bus rapid transit lanes would cut peak-hour delays in travel from Civic to Gungahlin from 16 minutes to eight minutes. The rail option could save another two minutes.

But the bus option offers much greater flexibility. The Light Rail would run from Gungahlin to Civic and only vehicles designed for the track could operate on it. On the other hand, a fast bus transit lane down Northbourne Avenue could take vehicles not only from the major centre of Gungahlin but also from Watson, Downer or even the Federal Highway. Presumably buses from O'Connor or Dickson could also swing into the fast lane at some point and save their passengers a few minutes travel every day. Every minute counts. If commuters find it is faster to travel by bus than by car, they are more likely to take the public transport option.

Light rail might appear sexy, but it offers no immediate advantages. If in time Canberrans found they had $400 million to spare, consideration could be given to converting the bus track to rail.

All sides of politics should back the bus option - better to get a real improvement in place than to battle for an idealised, costly alternative.

But, as always, petty politics is playing its part. If the usual point- scoring continues, nothing will be done, as illustrated by the never-ending discussion over the location of the second Sydney airport. According to former Labor transport minister Peter Morris, talk of a second airport site started in 1946. The Hawke Labor government bought land at Badgerys Creek but today there is still no agreement on development.

As the major gateway to Australia, Sydney's Mascot Airport is an embarrassment, put to shame by many airports in Asia, such as Singapore or Kuala Lumpur.

Nevertheless, the political hurdles to get a replacement seem insurmountable.

Badgerys Creek is clearly the best option, as recommended by the Joint Study on Aviation Capacity for the Sydney Region. But one look at the federal and state electorates around the site reveals immediately why it won't happen. Sitting on a knife edge, Federal Labor does not want to lose Chris Bowen in McMahon or David Bradbury in Lindsay. But it also has a problem with any expansion of Mascot, where the minister with primary responsibility for the airport issue, Anthony Albanese, holds the nearby seat of Grayndler and Peter Garrett has Kingsford Smith itself. Similarly, NSW Premier Barry O'Farrell does not want to lose the host of seats he won in the Badgerys Creek region in the recent state election. As a result he came up with the fanciful proposal that Sydney's second airport could be Canberra.

Even if a very fast train could bring passengers to the NSW capital in an hour, that would not be the only time taken to get to their destination. After the long flight to Australia, international passengers would have to go through Customs and Immigration. Then they would have to get to the train platform and wait for the next scheduled departure. How frequently would the trains go? And would they retain the same frequency 24 hours a day, 365 days a year?

And when they got to the other end of the line, passengers would still have to take another mode of transport to their ultimate destinations.

Taxis at Mascot might be expensive and badly organised but at the moment passengers can get to their destinations in one step.