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Integrated Variable Speed Limit Control to Minimize Recurrent Highway Congestions

Traffic Safety and Operations LabDept. of Civil and Environmental EngineeringUniversity of Maryland, College ParkMaryland State Highway AdministrationTraffic Safety and Operations LabDept. of Civil and Environmental EngineeringUniversity of Maryland, College ParkUniversity of Maryland Advanced Transportation Technologies Day2What is Variable Speed Limit (VSL)?A Variable Speed Limit (VSL) system:will change the speed limit dynamicallybased on the prevailing traffic conditions

Maryland State Highway AdministrationTraffic Safety and Operations LabDept. of Civil and Environmental EngineeringUniversity of Maryland, College ParkUniversity of Maryland Advanced Transportation Technologies Day3What does VSL include?

Traffic sensors

Variable message signsDatabase & communicationsControl algorithms (Speed limit)

45SPEED

Maryland State Highway AdministrationTraffic Safety and Operations LabDept. of Civil and Environmental EngineeringUniversity of Maryland, College Park

University of Maryland Advanced Transportation Technologies Day4Why Use VSL?Smooth speed transitionMitigate traffic congestionImprove traffic safety

Maryland State Highway AdministrationTraffic Safety and Operations LabDept. of Civil and Environmental EngineeringUniversity of Maryland, College ParkUniversity of Maryland Advanced Transportation Technologies Day5Field Demonstration SiteMD-100Two-lane highway in each directionSpeed limit 55 MPHHigh accident frequency (39 in 2008)High and dynamic traffic demand during peak hoursRapid speed drop at merging areas

50mph60mph20mph25mph40mphTravel time: Free flow: 180 secCongested: 600 secProject locationNLocation MapBaltimoreWashington DC

Maryland State Highway AdministrationTraffic Safety and Operations LabDept. of Civil and Environmental EngineeringUniversity of Maryland, College ParkUniversity of Maryland Advanced Transportation Technologies Day6System Design

ControlAB2 VMSDisplays advisory messagesTravel Time and/or reduced speed ahead2 VSLDisplay the control speeds from algorithm35SPEED45SPEED4 Detectors2 pairs LPR cameras

HD sensors Speed, volume (30 seconds)Matching LPs to calculate travel TimesDescriptions1234BNLocation Map35SPEED45SPEED

2134ABaltimoreWashington DC

Maryland State Highway AdministrationTraffic Safety and Operations LabDept. of Civil and Environmental EngineeringUniversity of Maryland, College ParkUniversity of Maryland Advanced Transportation Technologies Day7Data Collection Plan No Control

Travel time display onlyVSL and travel time displayVSL only

Maryland State Highway AdministrationTraffic Safety and Operations LabDept. of Civil and Environmental EngineeringUniversity of Maryland, College ParkUniversity of Maryland Advanced Transportation Technologies Day8Results (Speed for different locations)

VSL ControlMD 170MD 713MD 295Coca Cola Dr.1. Reduce Accidents2. Increase Speeds3. Reduce Fuel ConsumptionsAdvantages

Maryland State Highway AdministrationTraffic Safety and Operations LabDept. of Civil and Environmental EngineeringUniversity of Maryland, College ParkUniversity of Maryland Advanced Transportation Technologies Day9Results (Travel Time)No ControlTT Display OnlyVSL OnlyVSL & TT Display25%

Maryland State Highway AdministrationTraffic Safety and Operations LabDept. of Civil and Environmental EngineeringUniversity of Maryland, College ParkResults (Travel time over different periods)University of Maryland Advanced Transportation Technologies Day10

Maryland State Highway AdministrationTraffic Safety and Operations LabDept. of Civil and Environmental EngineeringUniversity of Maryland, College ParkResults (Throughput over different periods)University of Maryland Advanced Transportation Technologies Day11

*The Peak-Period of 30 Minutes **The Peak-Period of 1 Hour18831974204520363713384839803941

Maryland State Highway AdministrationTraffic Safety and Operations LabDept. of Civil and Environmental EngineeringUniversity of Maryland, College ParkUniversity of Maryland Advanced Transportation Technologies Day12Current Development

Source: FHWA

Maryland State Highway AdministrationTraffic Safety and Operations LabDept. of Civil and Environmental EngineeringUniversity of Maryland, College ParkUniversity of Maryland Advanced Transportation Technologies Day13Thanks & Questions?More info: attap.umd.edu

Maryland State Highway AdministrationTraffic Safety and Operations LabDept. of Civil and Environmental EngineeringUniversity of Maryland, College ParkDirection of Travel

Speed(mph)

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Direction of Travel

Speed(mph)

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