Corporation sources said that construction majors Larsen & Toubro, Afcons, Shapoorji Pallanji, V Mittal along with Gammon India had bid for the project. Gammon India will get a bonus of Rs 2,00,000 per day if it completes the work within the deadline, while the corporation will charge a penalty of Rs 3 lakh per day in case of time overrun.

The BrihanMumbai Municipal Corporation will contribute 30 per cent towards the project cost, while the rest will be borne by the Maharashtra State Road Development Corporation. The project was part of the Mumbai Urban Development Project-II, and was initially recommended by World Bank consultant Aktins in 1994. Atkins had suggested developing the JJ Hospital square and Crawford market as a bus corridor.

A commission, headed by Jog Engineering chairman Madhav Jog, in its report had strongly recommended a uniform two-carriageway structure without on or off ramps, given space constraints, to locate the main viaduct leaving no space for widening at ramp junctions. It had also recommended that the elevated section should be restricted to light vehicles only.

The JJ Hospital-Crawford Market flyover will have four lanes, while the six lanes on the existing roads will also be used for vehicular traffic. The flyover and the existing lanes will have more than 60,000 south-bound and 50,000 north-bound vehicles.

An MSRDC official said that a pre-cast segmental technology will be used in the project for the first time in Greater Mumbai. The technology was recently used at Bangalore by construction major L&T. With the use of the technology, the project's super structure will be developed within 10 days.

The dual carriageway width of the flyover will be 16.2 km, while the height will be seven meters. The structure comprises a prestressed concrete deck on approximately 35 meter spans supported on a single pier located in the median generally. The supports are in some instances moved apart to allow for the underground services that interfere with the desired location of these piers.

The construction of the elevated structure is designed to involve little disruption. The erection of the deck segments can be either by using an overhead launching girder, or by the use of an underslung truss. In both cases, the traffic on the existing road will not be interrupted except for a four-meter width on the median locally, the official said.