When he joined the city's planning body in 1964, the National Capital Development Commission, public transport was integral to its strategic thinking.

The population was 68,000, Lake Burley Griffin had just been completed and Canberra was a car-dominated and low-density dispersed city.

There were buses, Mr Westerman said, but light rail wasn't on anyone's agenda.

But as Canberra began to expand rapidly, there was a need to think big.

"The preferred plan was the Y plan with a centrally located 'urban busway', but some of us were aware that at some stage the form of public transport chosen should be capable of a higher capacity system," he said.

The "Y plan" was essentially the transport plan for long term growth in Canberra and derived its name from its form, with the arms reaching to Belconnen and Gungahlin (then called Mulligans Flat), and tail to Tuggeranong.

Mr Westerman said he became the accidental representative for the Organisation for Economic Co-operation and Development (OECD) committee on the Social Impact of New Transport Technology, and travelled worldwide for research.

"Informative but there was no discussion of automated driverless transport then," he recalled.

He reported back to the National Capital Development Commission on the research, but said it would be premature to make a commitment to technology, as long as the basic structure allowed for options including light rail.

"That was agreed, but interesting issues arose. I remember attending a parliamentary committee which was discussing the planning and design requirements for the 'New and Permanent Parliament House'. I suggested (tongue in cheek) that perhaps there should be provision for a light rail reservation deep in the basement."

Mr Westerman said the commitment to " a metro of some sort" was reflected in the city's planning, but there were issues that were not resolved.

"Issues about the actual route; vertical and horizontal alignment, crossing the lake, tunnelling under City Hill, grade separation. All of that was left for the future. Another issue was the type of corridor: express transport with few stops/stations or densely developed with frequent stops and higher density housing like Northbourne Avenue.

"No doubt all these issues have now been addressed and hopefully resolved. There will be new ones too in the coming age of artificial intelligence. But here is a great start and I hope the citizens will relish, use it and enjoy it."

Mr Westerman left Canberra in January 1979 and now lives in Brisbane. He said he never expected light rail to eventuate in the capital in his lifetime.

"There is a long lead time between idea and realisation," the 93-year-old said. "And I didn't expect to be around at my age."

He said while the idea might have seemed pie in the sky at the time, those sorts of things are now becoming a reality.

"Isn't Google experimenting with drones delivering coffee or pies somewhere in Canberra? That I would never have foreseen."

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