SEMCOG | Southeast Michigan Council of Governments

SEMCOG Bridge Condition Map:

This map shows bridge conditions based on the federal National Bridge Inventory (NBI) database. The map has ratings for bridges and culverts as of April 2024. The ratings are used to identify preservation, preventive maintenance, rehabilitation, and replacement needs. For more information about the Bridge data and for a more frequently updated source see the links below:

• Road Bridges
• Pedestrian Bridges

Download the data on this map here.

Instructions:

1. To acquire bridge condition data and additional information about a bridge, zoom into the bridge and click on it.
2. To disable autozoom, uncheck the box under the search icon in the top left corner of the map. This will keep map at desired extent as you change filters.

Definitions:

Condition ratings are based on a 0 to 9 scale and assigned to each culvert, or deck, superstructure, and substructure for each bridge. The ratings are recorded in the National Bridge Inventory (NBI) database. The bridge condition is determined by the lowest score for these bridge elements. If the lowest rating is greater than equal to 7, the bridge is classified as "good". If any of the bridge elements are less than or equal to 4, the bridge is classified as "poor". Bridges with the lowest element rated 5 or 6 are classified as "fair".

Bridge Status:

Weight limit signs may be posted on bridges to prevent loads that cause stresses above the safe limit of the structure. If the weight limit of a bridge is under 3 tons, it must be closed to traffic.

Culverts:

Bridges are structures that have a span greater than 20 feet. Structures with a span less than 20 feet are culverts..

Additional information provided includes:
- Road Name
- County
- Community
- Status

Contact: Visit SEMCOG's Bridge page for detail bridge information or contact Ed Hug for additional questions.