MADISON, Wis. (AP) — An audit finds that major highway projects completed in Wisconsin over the past decade cost twice as much as initially estimated.

The findings in a Legislative Audit Bureau report released Thursday come as the state Department of Transportation faces a nearly $1 billion budget shortfall.

The report finds that estimated costs for 19 major projects completed between 2006 and 2016 were $1.5 billion. That is $772 million more than initially projected.

The audit also finds that the estimated costs of 16 ongoing major highway projects have increased by $3.1 billion.

The Audit Bureau recommends that DOT use its money more effectively and improve how it manages the planning, engineering, construction and maintenance of state highways.

A Republican state senator says a highly critical audit of the Wisconsin Department of Transportation is "devastating" and will force major changes at the agency.

The nonpartisan Legislative Audit Bureau released its highly anticipated report Thursday. It found that DOT dramatically underestimated costs of completed and ongoing projects and failed to take into account inflation and other unexpected cost increases.

Sen. Rob Cowles is co-chairman of the Legislature's Audit Committee. He tells WHBY that the audit "will be devastating to the management of DOT." He says, "They have to do this whole thing differently."

DOT Secretary Mark Gottlieb resigned three weeks ago. Gov. Scott Walker had no immediate comment on the audit.