Company LOGO Ramp Meters Company LOGO What

Company LOGO Ramp Meters

Company LOGO What are Ramp Meters? • Part of Navi. GAtor, Georgia DOT’s Intelligent Transportation System (ITS) • Also includes electronic signs, cameras, website, and 511 system • “Traffic lights” on interstate entrance ramps designed to control traffic flow onto the interstate • Proven to relieve traffic congestion in over 20 U. S. cities for over 20 years

Company LOGO Why Ramp Meters? PPI Project Delivery

Company LOGO Why Ramp Meters? PPI Project Delivery

Company LOGO Why Ramp Meters? • Without metering, groups of closely-spaced vehicles (sometimes 15 -30 at a time) all enter the Interstate together. • At the merge point, they force their way into travel lanes, causing congestion- especially in the right lanes. • In already heavy traffic, there is a total breakdown of free -flow near the on-ramps. This has a ripple effect for Project many miles. PPI Delivery • Even with no incidents, heavy on-ramp traffic causes congestion that builds and lasts through the rush-hour.

Company LOGO How Do Ramp Meters Work? • Similar to traffic signals with red and green lights • Most effective when turned on prior to the onset of rush-hour • Cycle from red to green every 3 -5 seconds, allowing one vehicle at a time to merge onto the freeway. Project PPI Delivery • Yellow is not used, except on the very first cycle

Company LOGO Benefits of Ramp Meters • Reduced congestion on the Interstate • Faster overall travel times • Reduced merging accidents • Reduced fuel consumption • Reduced vehicle PPI emissions Project Delivery

Company LOGO Current Ramp Meter Locations • 4 on I-75 NB between Midtown and W Paces Ferry (1996) • 4 on the Downtown Connector SB (2005) • 130+ turned on during last 9 months PPI • About 30 more meters will be Project Delivery phased in within next 6 months, concluding the program the

Company LOGO Two-lane Ramp Meter Design On two-lane ramps, the meter operates in a ‘leftlane’, ‘right-lane’, ‘left lane’ manner. . PREPARE. . . TO STOP . . .

Company LOGO What if. . . ? • If too many cars start to back up on the ramp, automated sensors detect this and adjust the cycle to allow vehicles to move through faster. • If cameras show ramp traffic impeding surface street flow, the meters can be turned off completely. • There will be a short learning curve period in the first few days for each corridor as the public adapts and GDOT makes necessary adjustments. Project PPI • Delivery There is no “magic bullet” solution to eliminate congestion. Ramp meters are just one of several tools that can help fight it.

Company LOGO Fears / Actual Outcome § “The public won’t understand what to do at ramp meters” Fairly intensive PR campaign in advance of turn-on Motorists understand concept of red/stop; green/go § “There will be lots of accidents on the ramp” Did not occur “Prepare to stop” signs warn approaching traffic

Company LOGO Fears / Actual Outcome § “Ramp meters won’t help” Meters have “de-congested” several perennially congested segments of freeway Duration of congestion is reduced § “They’ll just shift the problem from the freeway to the surface streets” Most of the storage of vehicles occurs on the ramps, not the surface streets In cases where traffic spilled onto surface streets, special “flush” patterns were developed to temporarily turn meters off

Company LOGO Results Summary § Travel Time Reductions ranged from: 50 to 358 seconds 7. 9 – 34. 8 % § # of stop reductions ranged from: 0. 7 to 5. 3 (one corridor had a 0. 7 increase) § Total Delay Reductions ranged from: 13. 7 to 276 seconds 11. 4 to 81. 8 %

Company LOGO Results Summary, cont. § Emissions data also collected Hydrocarbon (g) reductions ranged from: § 4. 6 to 31. 4 % Oxides of Nitrogen (g) reductions ranged from: § 4. 8 to 38 % § One corridor increased 5. 8% Carbon Monixide (g) reductions ranged from: § 0. 8 to 14. 9 % § Two corridors had increases (0. 8% and 13. 3%)

Company LOGO Duration of congestion § Navi. GAtor detection data studied for 3 weeks before and after ramp meters

Company LOGO Duration of congestion Figure 19. Duration of Congestion: Wednesday (PM Peak – I-285 Westbound)

Company LOGO Duration of congestion Figure 6. Duration of Congestion: Friday (AM Peak – I-285 Eastbound)

Company LOGO