This photo of the airport tunnel was posted on the city's website in September. (City of Calgary)

The City of Calgary has handed over responsibility for the new airport tunnel to the Calgary Airport Authority now that the city has finished pouring the tunnel's concrete.

The handover will allow the Airport Authority to work on its new runway and taxiways that will be built on top of the tunnel.

Most of the work on the roads leading to the 620-metre long tunnel will be completed next year, with the tunnel expected to open for traffic in May 2014.

City officials say the tunnel is on budget at an estimated cost of $294.8 million.