Why the estimates went up on the tunnel project

New estimates released Wednesday show the price range for a waterfront tunnel has risen to a high of $5.5 billion, though the state says the "likely" cost is $4.6 billion. Both are far higher than an earlier $3.6 billion high-end estimate.

Here's a breakdown of some increased costs:

Materials and labor, up to $860 million

* Includes steel, concrete, copper, energy, and labor. High Inflation, up to $650 million

* Cost increases of up to 6 percent a year, and delays.

Market Uncertainty, up to $240 million

* The bidding climate is considered difficult, because contractors are so busy with other projects nationwide, including reconstruction of New Orleans following Hurricane Katrina.

Other risks, up to $140 million

Scope changes, up to $20 million

* A lid over the highway at Pike Place Market would increase costs. For Highway 520, the issues are similar, except for environmental issues such as fish protection, and costs to treat stormwater from the bridge pontoons.