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District Department of Transportation

Traffic Safety Investigations

Street in SE DC

DDOT is committed to making our city’s streets safer for everyone while providing multimodal mobility and access for residents, guests, and commercial users. A combination of traffic control devices and traffic calming measures can help meet both goals. Our Traffic Safety Investigation program provides a mechanism for DDOT to review roadway segments and intersection concerns to users, analyze existing conditions, and provide a plan for safety mitigations if warranted.

Residents should not request maintenance of existing assets through the Traffic Safety Investigation program; instead, please use the appropriate 311 categories (e.g. Roadway Sign, Sidewalk Repair, Traffic Signal Issue).

A Traffic Safety Investigation is initiated when a resident, ANC, or other community member or organization raises traffic safety concerns within the public right-of-way. When a traffic safety concern is identified, DDOT’s Roadway Safety Branch of the Traffic Engineering and Safety Division will perform a Traffic Safety Investigation to evaluate the extent of the safety issue and determine if any action is needed.

The Traffic Safety Investigation (TSI) Dashboard tracks the process from start to finish. Many of the TSI requests are complex and require review, data collection, or other investigations. DDOT is tracking to make sure residents can see where their request is in the process.

A Traffic Safety Investigation request takes approximately 130 business days to complete our investigation and produce the corresponding engineering design (work order). Once completed, DDOT will deliver the study results to the resident before closing out the request. If safety mitigation is necessary, DDOT will develop recommendations and prepare a work order for construction.

  • If the proposed recommendations change existing traffic control and/or on-street parking, a Notice of Intent (NOI) will be issued by DDOT, which includes a 30 business-day public comment period.
  • The timeline for installation of improvements varies based on the safety mitigation identified.
  • For most mitigations that do not require an NOI, installation typically occurs in the next calendar quarter after the TSI is completed; for example, a TSI request completed in Quarter 1 will be implemented in Quarter 2.
  • TSI service requests will be closed after a work order is produced.

Residents can visit for updates on work order installation.

For more information about vertical traffic calming infrastructure (e.g., speed humps, speed tables, raised crosswalks), including criteria used by DDOT to evaluate implementation on roadways within the District, as well as design specifications for these devices, please refer to DDOT Vertical Traffic Calming Guidelines

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