I-95 Variable Speed Limits (complete)
Project Description: The I–95 Variable Speed Limits (VSL) is a pilot project to implement VSL on the northbound lanes of I–95 between mile markers 115 and 130 in Caroline and Spotsylvania counties, and the City of Fredericksburg. This area is characterized by day–to–day speed variability and high crash rates. The project objective is to reduce speed variability, improve throughput, and reduce crashes through the use of VSL that is responsive to real–time traffic conditions.
Project Status: Planned
Project Stakeholders:
Interconnect and Flow
Diagrams
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Project Information Flows:
Project Functional Requirements (Element - Functional Object):
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Fredericksburg District VSL WAW Exchange - RSE Traveler Information Communications
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9: The field element shall provide vehicle current traffic metering status for in-vehicle signing.
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Private Sector ISP Centers - ITS Data Subscription Management
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1: The ITS Object shall support peer-to-peer communications with other ITS Objects to support operational data sharing.
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2: The ITS Object shall allow users to sign up for a data subscription service to access data held by the ITS Object.
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VDOT Fredericksburg District VSL Data Lake - DDS Data Access Management
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3: The data support center shall distribute to other Centers data which has been validated, aggregated, integrated, and sanitized.
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VDOT Fredericksburg District VSL Data Lake - DDS Data Collection and Aggregation
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5: The data support center shall collect data from other Centers.
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VDOT Fredericksburg District VSL Signs - Roadway Variable Speed Limits
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3: The field element shall receive commands from the controlling center that establish speed limits by lane.
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VDOT Fredericksburg District VSL Static Signs - Roadway Variable Speed Limits
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3: The field element shall receive commands from the controlling center that establish speed limits by lane.
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VDOT NOVA District MPSTOC - TOC/ATMS - TIC Data Collection
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1: The center shall collect, process, and store traffic and highway condition information, including incident information, detours and road closures, event information, recommended routes, and current speeds on specific routes.
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VDOT NOVA District MPSTOC - TOC/ATMS - TMC Basic Surveillance
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1: The center shall monitor, analyze, and store traffic sensor data (speed, volume, occupancy) collected from field elements under remote control of the center.
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6: The center shall maintain a database of surveillance equipment and sensors and associated data (including the roadway on which they are located, the type of data collected, and the ownership of each).
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7: The center shall remotely control devices to detect traffic.
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VDOT NOVA District MPSTOC - TOC/ATMS - TMC In-Vehicle Signing Management
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1: The center shall format and output sign information such as traffic and road conditions to field equipment that supports in-vehicle signage communications.
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VDOT NOVA District MPSTOC - TOC/ATMS - TMC Variable Speed Limits
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2: Based on the measured data, the center shall calculate and set suitable speed limits by lane.
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3: The center shall control field equipment that posts the current speed limits and displays additional information such as basic safety rules and current traffic information to drivers.
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4: The center shall monitor the operational status of the variable speed limit equipment, including fault reports.
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6: The center shall provide the current speed limits and additional information such as basic safety rules and current traffic information to drivers.
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VDOT NOVA MPSTOC - TOC Detection - Roadway Basic Surveillance
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1: The field element shall collect, process, digitize, and send traffic sensor data (speed, volume, and occupancy) to the center for further analysis and storage, under center control.
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Vehicle Display - Vehicle Traveler Information Reception
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2: The vehicle shall receive advisory information, such as evacuation information, proximity to a maintenance and construction vehicle, wide-area alerts, work zone intrusion information, variable speed limits, tunnel entrance restrictions, border crossing advisories, and other special information.
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VSP Center - MPSTOC - TMC Variable Speed Limits
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1: The center shall monitor data on traffic and environmental conditions collected from sensors along the roadway.
Standards:
Project Operational Concepts:
Last Updated 5/22/2026
