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Intelligent Transport Systems
ITS Applications: Freeway Management
Systems
ITS Lectures Overview
Lecture 1: ITS Overview & Fundamentals, Systems Engineering
Approach
Lecture 2: ITS Applications: Freeway Management Systems
Lecture 3: ITS Applications: Freeway Management Strategies
Lecture 4: ITS Applications: Public Transport Systems
Lecture 5: ITS Applications: Arterial Management Systems
Lecture 6: Hot Topics: Connected and Autonomous Vehicles,
Autonomous Vehicle, Smart City, Big Data and others
Tutorial: ITS Design - Freeway Management Systems device
placement, and other applications
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FREEWAY MANAGEMENT STRATEGIES
Typical relative improvement for several ITS measures
60
Percentage of overall
benefits
50
40
30
20
10
0
Recurrent
congestionmotorist
information
Non-recurrent
congestionmotorist
information
Non-recurrent
congestionreduction of
incident
clearance time
Ramp metering
Motorist service
patrols
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Freeway Management Strategies
Capacity Enhancement
Demand Management
Management and Operations
Capacity Enhancement example: Ramp
Management and Control
2020/08/26
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Single lane ramp metering system layout
LEGEN
D:
STOPLINE
RAMP METERING SIGNALS
M
M
FREEW
AY
I
M
ME
ADVANCE RAMP CONTROL
WARNING SIGN WITH
FLASHING BEACON
CHECK-IN DETECTOR
(MULTIPLE DETECTORS MAY
BE USED)
o
CHECK-OUT
DETECTOR
Q
QUEUE
DETECTOR
CONTROLLER
FRONTAGE ROAD OR SURFACE STREET
M
MAINLINE
DETECTOR
ME
OPTIONAL MERGE DETECTOR
Ramp Management
• Signal on entrance ramp
to manage flow of traffic
onto freeway
7-8
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Example: Twin Cities Evaluation
Crashes – 21% reduction with metering
Travel time – 22% increase without metering
Avg. speed – 7% reduction without metering
Throughput – 14% reduction during peak
periods without metering
Overall – 5:1 benefit/cost ratio
Demand Management Strategies: HOV /
Transit Facility Improvements
2020/08/26
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Benefits
Vehicles Persons
(approx)
Single
Occupant
Vehicle
45
45
Carpool
(2/car)
22
45
Carpool
(3/car)
15
45
Vanpool
(8/van)
6
45
Bus
1
45
Benefits
Travel time savings
More predictable travel times
Increase person throughput
Enhance transit operations
Environmental and air quality
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Benefits in Los Angeles County
Travel time savings in HOV lanes
• AM Peak = 1 to 25 minutes
• PM Peak = 1 to 33 minutes
Person-trips in PM peak hour
• 6000+ in carpool lane
• ~2000 in all other lanes on same facility
Types Of HOV Facilities
Exclusive
Barrier separated
Buffer separated
Non-separated
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Exclusive
Barrier Separated – Reversible
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Barrier Separated – Bi-directional
Buffer Separated
2020/08/26
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Non-separated
Demand management: Managed lanes Display Options
Separate Lane and Queue Warning
Integrated Full-Color Displays
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Freeway Management Systems
Variable Speed limits
• Speed Harmonization
Postpone or prevent freeway traffic breakdowns
Dampen shockwaves moving upstream
Harmonize traffic flow & speeds across lanes during peak
periods
Eliminate large speed differentials to reduce vehicle crashes
• Weather/Visibility
Freeway Management Systems
Queue Warning
• Informs motorist of reason for slower speeds
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Freeway Management Systems
Hard Shoulder Running
Dynamic Hard
Shoulder
Running
(Visualization)
Fixed Schedule
Hard Shoulder
Running
Freeway Management Systems
Managing Non-Recurring Congestion
(Incident Management)
Managing and preparing for these events is an
operational philosophy that supports and becomes a
foundation for transportation system management
and operations (TSMO).
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Freeway Management Systems
Traffic Incident Management (TIM)
TIM consists of a planned and coordinated multidisciplinary
process to detect, respond to, and clear traffic incidents so that
traffic flow may be restored as safely and quickly as possible
Effective TIM reduces
the duration and impacts
of traffic incidents and
improves the safety of
motorists, crash victims,
and emergency
responders
25
Freeway Management Systems
TIM Process
Detection
Verification
Response
Traffic
Management
Site Management
Traveler
Information
Clearance/Removal
After-Action Review/
Debrief
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Freeway Management Systems
Incident Timeline: What Does Safe Quick
Clearance Mean?
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Freeway Management Systems
Select Special Cases
• Work Zone Management
• Goods Movement
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Freeway Management Systems
Work Zone ITS
• Traffic management systems
Traditional traffic management
Monitoring
Signals
Ramp metering
Dynamic merge systems
Variable speed limit / Active Traffic Management (ATM) systems
•
•
•
•
Traveler information systems
Incident management systems
Intrusion alarm systems
Automated speed enforcement / feedback systems
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Freeway Management Systems
Goods movement application: Safety Hotspots
Oregon Downhill Speed Information System
• Upstream WIM
relates weight to
transponder in
truck to issue
advisory
• Public information
campaign
• 13 percent
reduction in
crashes
30
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Freeway Management Systems
Truck Parking
UDOT Truck Parking Program
31
16