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US-23 Improvement Project Study - Ann Arbor

MDOT is undertaking an Environmental Assessment (EA) study on US-23 in Washtenaw County between M-14 and I-94. These questions are a combination of questions raised at the group and public meetings, public survey responses, and other outreach to MDOT.   

Learn more about the US-23 Improvement Project Study, Ann Arbor.

  • The project limits are US-23 from the I-94/US-23 interchange area north to east M-14/US-23 interchange area in the city of Ann Arbor, Pittsfield Township, and Ann Arbor Township in Washtenaw County.


  • The environmental assessment of the project is scheduled to be completed in September 2024. The design is scheduled to be completed in 2026, with construction in 2027-2029.

  • Coordination is ongoing to address Federal Highway Administration (FHWA) guidance, which is new and developing, as well as required on the project. Coordination is also ongoing with the Southeast Michigan Council of Governments (SEMCOG), the Washtenaw Area Transportation Study (WATS), and the City of Ann Arbor, and regional and local goals will be reviewed as part of the project.

    A2Zero Climate Action Plan

    Resilient Washtenaw

    MI Healthy Climate Plan


  • The draft purpose and need of the US-23 corridor project between M-14 and I-94 is to improve safety and mobility, address existing and projected traffic congestion, improve operations for all users, and upgrade the aged infrastructure, while minimizing impacts to the natural environment and adjoining properties, and enhancing and preserving positive benefits to the community, businesses and roadway users.

  • An EA is a concise public document that serves to provide sufficient evidence and analysis regarding the significance of environmental impacts of the proposed action.

  • September 2024.

  • A traffic noise study along the entire project corridor is being completed as part of the environmental clearance process. If traffic noise impacts are identified and determined to meet federal thresholds for a residential impact, noise abatement will be reviewed. Noise abatement can take several forms, but noise barriers (walls) tend to be the most practical and cost effective.

    The FHWA will only fund noise walls that meet certain criteria:

    1. It must be effective, meaning it will noticeably reduce noise levels for nearby residents.
    2. The construction cost ($45 per square foot for the single side face surface of barrier) divided by the number of benefiting units is equal to or less than $52,248 (2023) per benefiting unit.
    3. The wall is physically able to be built without any major utility or other conflicts or without creating any safety concerns.
    4. The majority of those who would benefit from the wall must vote in favor of construction.

    Studies have shown that noise barriers are ineffective at providing mitigation for locations 500 feet or further from the source.

  • Based on the findings and recommendations from previous studies completed along this corridor, there is one no-build alternative and three additional alternatives being studied:

    • The no-build alternative would be to rebuild the existing lanes to current design standards with no added lanes.
    • The general purpose lane alternative would be to add one general purpose lane in each direction.
    • The HOV lane alternative would be to add one lane in each direction for vehicles with two or more people during peak travel hours and for general use outside of peak hours of the day.
    • The flex lane alternative would provide a new lane in the shoulder, which would only be open during peak hours.
  • A safety study analyzing the most recent five years of available crash data within the study area, including the interchanges, is being conducted. Mitigation measures will be recommended and implemented with the project to address historical crash trends. In addition, predictive analyses methodologies will be employed to assess the effectiveness of each proposed alternative in addressing those historical crash trends.

  • In response to previous median crossover crashes along this corridor, MDOT is currently completing a project to install high-tension cable median barrier along US-23 from south of I-94 to Geddes Road. Going forward, each of the proposed alternatives will evaluate the safety needs as part of the study to prevent crossover crashes by recommending concrete barrier, guardrail or cable barrier where there is a history of crossover crashes.

  • MDOT is coordinating with local agencies to develop a common understanding of the needs and priorities for nonmotorized access and connectivity crossing US-23. While not all the bridges are currently planned for replacement or major repairs, MDOT is seeking to leverage project funding to the greatest extent possible to attain nonmotorized goals wherever feasible.

  • An operational and safety analysis will be performed at these closely spaced intersections. This analysis is also being coordinated with the ongoing Washtenaw Planning and Environmental Linkages (PEL) study, which includes coordinating with the City of Ypsilanti, Ypsilanti Township, and Pittsfield Township, plus collaboration with The Ride for a long-term vision of this area. There are a few alternatives being investigated as part of both studies. Coordinated efforts will continue throughout project development.

  • Demand is a function of population, land use, and socioeconomic activity, while the capacity of the roadway network is linked to people choosing certain routes. As people tend to choose the most efficient route to reach their preferred destination (i.e., the fastest path), widening US-23 may become attractive for some motorists who are currently using local streets in lieu of US-23. The SEMCOG regional transportation model is being used to estimate this induced demand and will be accounted for in the operational and safety analysis of the alternatives that add capacity to US-23.

  • Based on current data, 40-50 percent of the current traffic on US-23 is through-traffic (regional/commercial) not having an origin or destination in Ann Arbor. These estimates are based on data from Replica, which uses existing crowd-sourced data that is consistently updated using various data sources.  

  • MDOT is coordinating with The Ride for a long-term vision of this corridor. As part of the environmental process, MDOT will analyze planned 20-year improvements from all agencies in the study area and evaluate them with all the study alternatives.

  • MDOT is coordinating with The Ride as part of this study and is looking to help improve accessibility to the existing Plymouth Road park and ride lot. Currently, The Ride does not have any other park and ride lots planned within in the study corridor of US-23 from north of I-94 to south of M-14. MDOT will assess transit usage of the HOV lane alternative along US-23, which would assist buses with operational efficiency along the corridor.

  • The US-23 roadway pavement will be rebuilt to improve the condition of the road and likely reduce noise caused by poor pavement conditions. While some of the bridges in the corridor are not currently planned to be rebuilt, they will be repaired and improved.

  • As part of the study, an aesthetic guide will be developed with the community. The aesthetic improvements from the guide will be implemented when the corridor is rebuilt.

  • The project is anticipated to be under construction from 2027-2029.

  • The project website is available for information, questions, comments with an interactive mapping tool, and feedback at We look forward to you staying engaged.