Closing parts of Park and Portland Avenues to make way for a park near the new Vikings stadium would cause major traffic disruptions in that part of downtown, according to a new report.

In a draft of the Alternative Urban Areawide Review and Mitigation Plan, closing a one-block segment of Park and Portland avenues between 4th and 5th Streets would bring noticeable increases in traffic and congestion on surrounding streets during the morning and evening rush hours.

No decision has been made on whether to close the streets entirely.

Other options include reducing both streets to two lanes and having them open only during peak periods.

The report said closing the roads could eliminate street parking and increase traffic on other nearby streets such as Washington, Chicago, 4th and 5th Avenues.

It also noted that any closures or reconfiguration could delay emergency response times for nearby Hennepin County Medical Center.

Any changes to Park or Portland Avenues need the approval of the Hennepin County Board because they are county roads. The City of Minneapolis has jurisdiction of 4th and 5th Streets.

Last week the board heard from Ryan Companies Vice President Rick Collins about the planned $400 million mixed-use development west of the new Vikings stadium. Collins explained the company's goal to close all or parts of Park and Portland Avenues to enhance the "urban park experience" at 4th Street and Portland Avenue S.

Board members have expressed opposition to restricting traffic because of concerns about access to the hospital. Collins said building a bridge over or a tunnel under Portland would be too expensive.

Board Chairman Mike Opat said the county won't take a stand on road issues until the Minneapolis City Council makes a recommendation.