The repair bill for the Acton tunnel crash that blocked traffic for two days in 2015 will be $1.2 million, with the damaged tiles to be replaced.
Roads ACT director Tony Gill said the 80 damaged tiles from the westbound tunnel over Parkes Way would be covered by "like-for-like" insurance arrangements.
With the price tag equating to $15,000 a tile, Mr Gill said the option of replacing all the asbestos-containing tiles in both tunnels was not viable.
The price was in addition to the $260,000 of costs incurred by Roads ACT for the immediate clean-up after an excavator on the back of a truck hit the roof on the morning of October 20, 2015.
Those immediate costs were also covered by insurance.
Mr Gill said the tiles weighed 80 kilograms each and those damaged made up less than 10 per cent of all the tiles in the westbound tunnel, despite covering an area about 60 metres long.
"We'll be looking for a tile that doesn't have any asbestos in it, obviously, and a fixing arrangement that is lighter and easier to put in place," he said.
A replacement of all the tiles in the tunnels would be "ultimately required" in time, he said.
"The balance of the tiles still have asbestos in them, so if there was to be a similar incident, then the same sort of consequences are in place, but what is there at the moment is functional and doesn't pose any safety considerations," he said.
Designs were now being prepared and the tile installation was planned to be completed by the end of June, with physical works likely to start several weeks before then.
Mr Gill said the ACT government paid about $3 million a year for insurance premiums to cover all public roads infrastructure, and he understood the excess fee for the tunnel claim was about $10,000.
It was the fifth major roads claim he was aware of since 2001, with others caused by fires and bad weather.
The decision to replace the tiles and fill in the exposed roof areas was made for aesthetic reasons and to dampen the vibrations from the general traffic, he said.
The October crash shut the westbound tunnel for more than 50 hours, and the speed limit returned to the usual 90km/h only a month after it reopened.
A WorkSafe investigation into the driver was continuing and no penalties had been imposed.