Revised plans to improve the A303 around historic Stonehenge in Wiltshire have been published.
A cut and cover tunnel may be an option to bypass the stones
Proposals to bore a road tunnel taking traffic away from the ancient monument had been approved in 2004.
But last July, the Highways Agency was ordered to review the scheme after the estimated cost escalated to £510m.
A cheaper tunnel option has been put forward, together with a number of other schemes, all of which will now go out to public consultation.
Options include a "cut and cover" tunnel, which is cheaper than a deep-bore passage and involves creating a shallow channel and covering it with a roof.
Other possibilities include a bypass to the north or south and changes to the Countess Roundabout.
Stephen Ladyman, Minister of State for Transport, said: "The government is committed to improving the A303 past the World Heritage Site at Stonehenge.
"I hope that everyone with an interest in this important issue will take this opportunity to contribute to the review process."
Culture minister David Lammy added: "This review is an important stage in our work. We need to find a solution for the A303 past Stonehenge that is right for the setting of the stones and right for the historic landscape which surrounds them."
The public consultation period runs from 23 January to 24 April 2006, with public exhibitions being held in Salisbury on 9-11 February 2006 and in London on 17-18 February 2006.
Alternatives to the underground road tunnel at the site could threaten the recovery of one of Britain's rarest birds - the stone curlew - the RSPB has warned.