I-43 North-South Freeway

The I-43 North-South Freeway is one of Wisconsin's busiest corridors and serves as a vital interstate link, connecting southeastern Wisconsin to the rest of the state.

Future projections show that by 2045, traffic is expected to increase by 9,700 vehicles per day to the north end of I-43 and by 15,000 vehicles per day to the south end of I-43. Covering a 14-mile stretch, the updated I-43 North-South Freeway will meet existing and projected traffic volumes. The Wisconsin Department of Transportation selected HNTB, who collaborated alongside JT Engineering, Benesch, Collins Engineers, and Lakeside Engineers, to provide construction engineering and inspection services for approximately four miles of I-43.

The I-43 North-South, South End Project replaces the existing deteriorating pavement, widens the existing local bridges, reconstructs multiple local intersections, reduces congestion, and improves safety while minimizing impacts to local businesses and stakeholders.

Key improvements include:

• Expanding I-43 north south from four to six lanes, with three lanes in each direction
• Reconstructing the existing Brown Deer Rd local road into southeast Wisconsin’s first diverting diamond interchange (DDI)
• Reconstructing Jean Nicolet Rd. along the west side of I-43 north south
• Replacing the Union Pacific railroad bridge over I-43 in Glendale
• Reconstructing Port Washington Road in Glendale from bi-directional traffic to a divided road with new bike lanes in both the north and south directions

In addition to CEI services, HNTB also provided design services throughout the entire corridor. HNTB is currently providing traffic mitigation strategies and public involvement efforts to ensure minimal disruption and maintain safety. The firm manages daily traffic staging with not only the I-43 North-South, South End Project, but the entire I-43 corridor, ensuring that emergency vehicles and pedestrians can move safely through and around construction zones. HNTB’s public involvement team maintains communication with residents, businesses and stakeholders, providing updates on construction activities and responding to questions or concerns.