Laminar Traffic Flow And Dynamic Hard Shoulder Utilization


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Presentation of the BroadBit entry for the showdown of ITS-America's 2009 ITS challenge.

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Laminar Traffic Flow And Dynamic Hard Shoulder Utilization

  1. 1. Laminar traffic flows and Dynamic hard shoulder utilization - Enhancing efficiency of existing road infrastructure
  2. 2. Two simple rules are applied on urban highways: 1. Vehicles can utilize hard shoulders but only at appropriately low speed. This ensures safe use of hard-shoulders. 2. There is a growing minimum distance of 'sticking within the lane' towards the middle of the road. A sensible criteria is along these lines: - outermost lane: no restriction - 2nd lane from outside: at least 1 km or mile straight driving before switching to outer lane - 3rd lane from outside: at least 10 km or mile straight driving before switching to outer lane
  3. 3. 1st effect: Traffic flows more smoothly when unnecessary lane changes are avoided Hard shoulder Lane changes disrupt traffic flow and reduce capacity Transit traffic flows through, fewer lane changes increase traffic capacity Hard shoulder
  4. 4. 2nd effect: Transit flows are less affected by local congestions Hard shoulder Transit flows are hindered by each locally arising congestion Transit traffic flows are much less affected by local congestions Hard shoulder It is also checked that drivers don’t try to skip the exit queue, holding up everyone else, but get on exit ramp lane at end of queue.
  5. 5. 3rd effect: Traffic capacity is increased by utilization of hard shoulders Hard shoulder Hard shoulder capacity is not utilized Hard shoulder capacity reduces congestion during peak hours Hard shoulder
  6. 6. Tackling congestion must start with making best use of existing road infrastructure. Cost-efficient enforcement of these proposed rules is the key to deployment success. Recent technology breakthroughs make cost- efficient enforcement possible.
  7. 7. Lamp-pole installation 200 meters Hard shoulder Hard shoulder Broadband power- line data link Laser scanners for lane monitoring License plate recognition camera for vehicle matching
  8. 8. Hard shoulder Hard shoulder Vehicle distance is measured Each laser-scanner tracks all by time-of-flight measurement vehicles’ position for more than at 10 cm accuracy. Rate of 100 meters range, under all distance change reveals weather and lighting conditions standstill or slow vehicles
  9. 9. Hard shoulder Hard shoulder 200 Mbits/s capability Power-line communications units Ethernet interfaces are also installed onto lamp- Lightning protected outdoors poles, creating an instantaneous equipment broadband network. Distance between nodes up to 400 meters Terminating power-line gateways Nodes can be chained for can be directly connected to fiber bridged data forwarding (G-PON data transport).
  10. 10. Infrastructure enforces good driving: - Vehicles drive slowly in hard shoulder - Inner lanes are for transit driving - No excessive lane switching - No queue skipping
  11. 11. Many variations of this solution are possible - customers may select most suitable one: - Laminar traffic flows with Dynamic hard shoulder use - Only Laminar traffic flows / Only Dynamic hard shoulder use - Innermost lane is tolled express lane ... further varieties of above options
  12. 12. Most importantly, enforcement scheme must be acceptable to drivers THR-452: You are driving over 20 mi/h on hard shoulder! THR-452: You are skipping exit queue! THR-452: You have been repeatedly driving Option 1: Instant short distances in middle lane! VMS warning Option 2: Option 3: warning letter fine
  13. 13. Overview of other congestion management approaches’ deployment aspects Congestion Matched Ride Partial use of Pricing (Tolling) Sharing Public Transport ✓ Can be quickly ✓ Increases traffic ✓ Increases traffic deployed capacity capacity in centers ✓ Effective ✓ Appealing to public ✓ Suited for city center ✓ Moderate capital ๏ Low initial matching ๏ Amount and security requirement rate and congestion of P+R parking may reduction rate be low ๏ Overall traffic capacity is not ๏ Psychology barrier ๏ Public transport is increased for many drivers sparse in some cities ๏ Drivers dislike the ๏ Costly tracking box, ๏ Mostly applies just to idea of being few mobiles good periphery-to-center priced off the road for auto-tracking journeys
  14. 14. Deployment aspects of this solution Laminar traffic flows and Dynamic hard shoulder utilization ✓ Increases traffic capacity ✓ Can be quickly deployed, with immediate effect ✓ Effective congestion alleviation, as it applies to all traffic over deployed road segment ✓ Moderate capital requirement ✓ Appealing to public, especially in contrast to risks created by hard-shoulder use without proper control (e.g. I-95 Boston loop)
  15. 15. Optional future extensions Traffic dependent speed limit for optional traffic flow is dynamically calculated and informed via VMS signs Hard shoulder Hard shoulder Ramp metering ensures safe highway entry Traffic engineering is taken to the next level!
  16. 16. Recent laser-scanner and power-line communication technologies make it possible to smooth traffic flows cost-efficiently! Everyone benefits from the extra lane capacity and less turbulent driving Smooth and laminar traffic flow carries more dense traffic!