2. Traffic Safety and Operations Lab Dept. of Civil and Environmental Engineering University of Maryland, College Park Maryland State Highway Administration Integrated Variable Speed Limit Control to Minimize Recurrent Highway Congestions

3. Traffic Safety and Operations Lab Dept. of Civil and Environmental Engineering University of Maryland, College Park Maryland State Highway Administration University of Maryland Advanced Transportation Technologies Day 2 What is Variable Speed Limit (VSL)?  A Variable Speed Limit (VSL) system:  will change the speed limit dynamically  based on the prevailing traffic conditions

4. Traffic Safety and Operations Lab Dept. of Civil and Environmental Engineering University of Maryland, College Park Maryland State Highway Administration University of Maryland Advanced Transportation Technologies Day 3 What does VSL include? 45 SPEED

5. Traffic Safety and Operations Lab Dept. of Civil and Environmental Engineering University of Maryland, College Park Maryland State Highway Administration University of Maryland Advanced Transportation Technologies Day 4 Why Use VSL?  Smooth speed transition  Mitigate traffic congestion  Improve traffic safety

6. Traffic Safety and Operations Lab Dept. of Civil and Environmental Engineering University of Maryland, College Park Maryland State Highway Administration University of Maryland Advanced Transportation Technologies Day 5 Field Demonstration Site  MD-100  Two-lane highway in each direction  Speed limit 55 MPH  High accident frequency (39 in 2008)  High and dynamic traffic demand during peak hours  Rapid speed drop at merging areas 50mph 60mph 20mph 25mph 40mph Travel time: Free flow: 180 sec Congested: 600 sec PROJECT LOCATION N Location Map Baltimore Washington DC

7. Traffic Safety and Operations Lab Dept. of Civil and Environmental Engineering University of Maryland, College Park Maryland State Highway Administration University of Maryland Advanced Transportation Technologies Day 6 System Design Control A A B B 2 VMS Displays advisory messages Travel Time and/or “reduced speed ahead” 2 VSL Display the control speeds from algorithm 35 SPEED 45 SPEED 4 Detectors 2 pairs LPR cameras HD sensors Speed, volume (30 seconds ) Matching LPs to calculate travel Times Descriptions B B N Location Map 35 SPEED 45 SPEED A A Baltimore Washington DC

8. Traffic Safety and Operations Lab Dept. of Civil and Environmental Engineering University of Maryland, College Park Maryland State Highway Administration University of Maryland Advanced Transportation Technologies Day 7 Data Collection Plan

9. Traffic Safety and Operations Lab Dept. of Civil and Environmental Engineering University of Maryland, College Park Maryland State Highway Administration University of Maryland Advanced Transportation Technologies Day 8 Results (Speed for different locations) VSL Control MD 170MD 713MD 295 Coca Cola Dr. 1. Reduce Accidents 2. Increase Speeds 3. Reduce Fuel Consumptions Advantages

10. Traffic Safety and Operations Lab Dept. of Civil and Environmental Engineering University of Maryland, College Park Maryland State Highway Administration University of Maryland Advanced Transportation Technologies Day 9 Results (Travel Time) No Control TT Display Only VSL Only VSL & TT Display 25%

11. Traffic Safety and Operations Lab Dept. of Civil and Environmental Engineering University of Maryland, College Park Maryland State Highway Administration Results (Travel time over different periods) University of Maryland Advanced Transportation Technologies Day 10

12. Traffic Safety and Operations Lab Dept. of Civil and Environmental Engineering University of Maryland, College Park Maryland State Highway Administration Results (Throughput over different periods) University of Maryland Advanced Transportation Technologies Day 11 *The Peak-Period of 30 Minutes **The Peak-Period of 1 Hour 1883 1974 20452036 3713 384839803941

13. Traffic Safety and Operations Lab Dept. of Civil and Environmental Engineering University of Maryland, College Park Maryland State Highway Administration University of Maryland Advanced Transportation Technologies Day 12 Current Development Source: FHWA

14. Traffic Safety and Operations Lab Dept. of Civil and Environmental Engineering University of Maryland, College Park Maryland State Highway Administration University of Maryland Advanced Transportation Technologies Day 13 Thanks & Questions? More info: attap.umd.edu