The REL-Hyundai consortium quoted a concession period of nine years and 11 months against 75 years quoted by Mukesh Ambani's Sea King Infrastructure Ltd, the only other bidder.
The Maharashtra State Road Development Corporation (MSRDC), the nodal agency for the project, had estimated that the project would be viable only if the winner operates the bridge and collects toll for at least 44 years.
MSRDC is re-evaluating the winning bid through a London-based technical consultant Dar Consultants and the report is expected within a fortnight. Confirming this, Minister for Public Works and MSRDC Chairman Anil Deshmukh said: "The concession periods demanded by both brothers seem to be unrealistic."
The REL-Hyundai consortium was supposed to have been given the Letter of Intent (LoI) within one month from the date it was declared the preferred bidder, which was February 20, but has not received it so far.
An REL spokesman declined to comment.
Phase I of the MTHL comprises a six-lane dual carriageway and Phase II, which is expected to be added in the period 2015-18, will consist of a double-track rail link that will run parallel to the road link.
Under the terms of the bid, the REL-Hyundai consortium has to complete construction of the first phase within five years and can charge Rs 250 per heavy vehicle and Rs 120 per vehicle for cars and other light commercial vehicles.
"REL seems to be banking heavily on multi-axle vehicles to recover its costs," said a senior official from the state's public works department. "Ours and the consortium's estimates differ almost by four to five times."
The official said the deparment had estimated that the sea link would carry 3,000 multi-axle vehicles per day in 2004, whereas REL hopes to attract traffic of 12,000 to 15,000 multi-axle vehicles per day.
Multi-axle vehicles attract the maximum toll, which is normally four to five times that of passenger cars.
The consortium's projections are based on traffic that will be generated by the special economic zones being set up by Mukesh Ambani, Indiabulls, Mahindra and Mahindra, Bharat Forge and others in the Raigad and Pune districts and two private ports that are coming up at Revas and Dighi in Raigad, the official added.
In its initial bid document, the REL-Hyundai consortium had also quoted projected revenues from utilising real estate on the either bank of the sea-link and through advertisements along the sea-link. However, MSRDC objected to this, citing coastal zone regulations, and the proposal was dropped, the official said.
The consultants' report will be sent to a high-powered committee on infrastructure headed by the chief secretary. This committee will send the report to the cabinet along with its recommendations.
Additional reporting with PB Jaykumar and Raghavendra Kamath
