Sound walls, fiber-optic cables and utilities would have to be moved, and drainage would have to be upgraded. A biking and walking trail along the interstate also would have to be adjusted.
The widening would be further complicated if two shoulders were included, one in each direction. Kilgore's campaign said it has not determined whether the plan would include shoulders, but VDOT officials and transportation experts said such an improvement should be included for safety reasons.
Although Kilgore wants to widen the highway in both directions, he has outlined how to pay for the eastbound lane only.
"The cost of this project is estimated at approximately $160 million," the Kilgore plan says, although campaign officials said the price tag might increase to $193 million.
The estimate is based on "preliminary numbers" from VDOT, according to the campaign.
Joan Morris, a spokeswoman for the agency, said that widening the westbound side would probably cost $112 million to $233 million but that VDOT does not have a cost estimate for widening the interstate in the eastbound direction.
VDOT officials speculate privately that widening the road in both directions would cost $224 million to $466 million, depending on the scope of the project.
The campaign said Kilgore would earmark $40 million a year in federal funds for the project, as well as an additional $33 million in other federal highway money, to reach the $193 million figure.
Asked how Kilgore might make up a difference that could range from $31 million to $273 million, Martin said: "We believe we'll be able to draw down federal dollars to complete the project. It's hard to give specific numbers when you're not in office."
Federal and state statistics show that new highway money from Congress over the next several years will probably range from $92 million to $105 million per year. However, congressionally earmarked projects take up a minimum of $50 million annually, records show.
That leaves $42 million to $55 million a year for all other projects where federal funds are needed, including extra money for widening I-66, according to VDOT officials.
