Maryland Route 99 Investigation

Howard County is undertaking an investigation into the transportation challenges facing residents in the MD 99 corridor. In 2017, during public meetings on the County’s 2018 Priority Letter, many residents shared their concerns about the safety and congestion challenges on MD 99, especially in the section between Marriottsville Road and the US 29/MD 99 intersection. Recognizing these challenges, the County initiated an investigation into the traffic, safety, and congestion challenges on the MD 99 corridor. The investigation is focused on gathering data and information and the impacts on residents.  The results will help guide future county and state actions.

MD 99 Corridor Investigation Report: 

The MD 99 Corridor Investigation originated in response to long-standing concerns by residents in neighborhoods bordering the corridor, as well as broader public concerns regarding safety and traffic in the corridor.

The County designed the project with the primary objective of developing short-term mobility solutions in the corridor to address five key themes which directly reflect public feedback and comments. These themes were used to structure the project; each theme was studied and analyzed to develop a range of recommendations around them. The findings and recommendations are presented an interactive online report format in which we detail the process, data, findings and recommendations. The interactive online report details:

  • The purpose of the project
  • Public comments and feedback
  • The study team
  • Previous studies and projects
  • Traffic data collection
  • Existing conditions, such as traffic volumes, sight line evaluations, traffic operations and the bike/pedestrian network.
  • Recommended mitigation strategies for selected intersections for sight distance, traffic operations and safety, presenting recommendations to add to the existing bike/pedestrian network to support safety and access to schools, as well as a Transportation Demand Management program.

The recommendations in the report are projects and programs that can address short-term mobility challenges.  Longer term solutions for I-70 and US-29 will need to be addressed by MDOT SHA through capacity improvements as well as the Transportation Systems Management and Operations Program.

The next steps are as follows:

  1. Public Comment Period (September 10 to September 30, 2019)
    1. Following the close of the public comment period, the project team will review comments to help guide the selection of recommendations and actions
  2. Project Planning and Design (12 months)
    1. Develop estimates for selected construction recommendations
    2. Advance selected non-construction recommendations, such as line of sight mitigation and signal adjustments
    3. Advance Transportation Demand Management recommendation
  3. Funding for Engineering and Construction
    1. The recommendations in this report are not currently funded and would need to be funded as part of county capital projects and/or the Maryland Department of Transportation’s Consolidated Transportation Program.

Please click here for the interactive online report. The online report also includes a comment form.

We have also developed a one-page summary document with the findings and recommendations. Please click here for the summary document.

MD 99 Corridor Investigation Report Appendices:

Appendix A Traffic Count Data

Appendix B Signalized Intersection Analysis 

Appendix C Public Comments

Appendix D Signal Timing at Intersections

Appendix E Traffic Signal Warrants 

December 11 Meeting Materials:

On Tuesday, December 11, 2018, the Office of Transportation held a meeting from 7 PM to 8:30 PM to share findings and recommendations from the Maryland Route 99 Corridor Investigation.

The investigation considered a wide variety of issues and concerns raised by residents, including:

  • Traffic volumes, queuing and traffic back ups
  • Travel times and travel speeds at different times of the day
  • Traffic signal operations
  • Challenges to making left turns onto MD 99 from side streets
  • Crashes
  • Impacts of school drop-off and pickup times on traffic
  • Ingress and egress at schools and school walk zones

The following materials were presented at the meeting, including a presentation, boards with existing conditions, findings and recommendations. Please review the presentations and boards and if you have any comments or questions please provide comments by:

We will also be developing written responses to some of the more detailed and complicated questions raised during the presentation. We will post them on the site as they are completed.

MD 99 Presentation

MD 99 Meeting Agenda

Information and Background Boards

Travel Speeds

Traffic Volumes

Aerial maps of the MD 99 corridor

Public comments since 2017

Development Activity


Origin and Destination Results

Recommendation and Feedback Boards

Signal and Geometric Recommendations

Sight Distance Mitigation Recommendations

Bicycle & Pedestrian Improvement Recommendations

Transportation Demand Management

 Open House Materials:

On Tuesday, February 6, 2018, the Office of Transportation hosted an open house from 5 PM to 8 PM at the at the George Howard Building (3430 Court House Drive, Ellicott City). The Open House provided a venue for community members to talk to staff and for staff to learn as much as possible from area residents to ensure the project team is are aware of the issues experienced by the people who live in the area and know it best. At the open house the Office of Transportation and MDOT-SHA had tables and boards with information we have gathered such as traffic volumes and crash data. Attendees had the opportunity to review the information, and to discuss issues and concerns one on one with county and state staff.

The following materials were presented at the Open House:

MD 99 Resources:

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