Twin Cities metropolitan-area freeway traffic congestion increased slightly between 2008 and 2009, from 17.3 percent to 18.2 percent overall, according to the Minnesota Department of Transportation in a report released this week.

Agency officials say that many factors affect congestion levels, such as the local economy, population growth, gas prices, transit ridership and vehicle miles traveled.

Congestion is expected to plateau or increase minimally over the next few years as current and planned highway projects near completion. MnDOT goals for addressing congestion include operational solutions, such as rapid clearing of traffic incidents, electronic message signs and ramp meters.

“MnDOT is also working closely with the Metropolitan Council and other partners to provide a safe, reliable and modern transportation system,” said Metro District Engineer Scott McBride. “The range of solutions includes cost-effective construction projects to improve traffic flow, high-occupancy voluntary toll lanes, expanded park-and-ride lots, bus shoulder bypass lanes and bus rapid transit projects.”

Highway construction projects completed between 2002 and 2009 have helped with the overall trend of declining congestion, MnDOT officials said. Some of the projects include the following:

Completion of the Urban Partnership Agreement project on I-35W which includes areas of increased capacity as will as a high-occupancy toll lane.

The new I-35W Mississippi River Bridge in Minneapolis.

Addition of lanes and “unweaving” at I-35E and I-694 in Vadnais Heights and Little Canada.

The new I-35E Mississippi River Bridge in St. Paul.

Lane additions in each direction of I-694 between Brooklyn Boulevard and I-494 in the northwest suburbs.

Lane additions in each direction of I-494 between Highway 55 and France Avenue in the southwest suburbs.

Lane additions on I-94 over McKnight Road east of St. Paul.

Lane additions on Highway 100 at Highway 7 in St. Louis Park.

Completion of the first of two bridges carrying I-494 over the Mississippi River in South St. Paul, adding a lane in each direction.

Other capacity-adding projects that will be completed in the coming years include:

Highway 62 (Crosstown) at Interstate 35W and Highway 62 in Minneapolis and Richfield.

Wakota Bridge/I-494 spanning the Mississippi River in South St. Paul and Newport.

Interchange reconstruction at Highway 169/County Road 81 in Brooklyn Center.

Completion of third lanes on I-494 between Highway 61 and I-94 in the east metro.

Highway 610 extension in Maple Grove.