The Straits Times reported that the development of Changi East, where the airport's Terminal 5 (T5) is being planned, will require major roadworks - including the possible construction of two parallel roads with a total of up to 20 lanes - to support the expected higher traffic volumes.

Under preliminary plans, both roads will run side by side for about three-quarters of a kilometre, before one breaks off and turns into the future T5, The Straits Times has learnt.

The other will lead to Changi Coast Road, which will be diverted from its current location as it separates the existing airport from the T5 site. The plan is for motorists to be able to access the new roads from the Pan-Island Expressway, East Coast Parkway and Xilin Avenue. All three will be expanded. Airport Boulevard will also become wider.

The development of Changi East, which aims to cement Singapore's position as a major airport for destination and connecting traffic, will include the construction of offices and hotels.

The authorities have to be mindful not to confine widening and expansion works to stretches near the airport, said National University of Singapore Transport Researcher Lee Der Horng. "It is important for the traffic capacity and flow to gradually build up and thin out so we avoid bottlenecks upstream and downstream."

Plans have been announced for a new ground transportation centre to serve the future T5 and Changi East, with at least one, if not two, new MRT lines.

With the number of passengers set to increase in the coming decades and competition from rival airports becoming more intense, it may also be time to consider an express rail service to Changi Airport, with city check-in and other related facilities, said Dr. Lee.

"In Hong Kong, the express train takes you from the airport to the city with just three stops in between. Once you reach the city, there is a comprehensive bus network to ferry travellers to all the main hotels in the area," he said.