Laminar Traffic Flow And Dynamic Hard Shoulder Utilization
1. Laminar traffic flows and Dynamic
hard shoulder utilization
- Enhancing efficiency of existing road
infrastructure
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. 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. 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. 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. 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. 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. 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. 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. Infrastructure enforces good driving:
- Vehicles drive slowly in hard shoulder
- Inner lanes are for transit driving
- No excessive lane switching
- No queue skipping
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. 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. 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. 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. 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. 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!
