The Indiana Division

Use of Technology to Address Congestion

Indiana Congestion Conference
August 5, 2008

Mac Lister
FHWA Resource Center

Discussion Topics

• Problem definition
• Strategies
• Applications and benefits

The Mobility Problem

No longer a big city problem-Congestion in small areas grew 300%!

Everyone in the transportation business has seen graphs like this. This problem was recognized in the early days of ITS 1990… and the strategic plan was intended to address it. The point of the graph is that mobility is deteriorating rapidly due to increasing demand and constant supply.

Why Such a Big Deal About Congestion?

• Engineers and elected officials have used it to define the state of the system
• Reported by States to the Highway Performance Monitoring System (HPMS)
• Implicitly represents the balance of supply and demand

Becoming thought of as an outmoded measure. In addition to its definitional problems, it doesn’t take into consideration how long the congested period lasts. AND it doesn’t represent non-recurring congestion.

Congestion Measurement Issues

• Selection of appropriate variable (speed, density, etc.)
• Selection of appropriate times-of-day (when is the peak period)
• Use of appropriate sampling methodology (representative days and roadway segments, sample size, avoiding incidents, etc.)

Could discuss the need for the same peak period at all locations vs. tailoring the peak to the traffic.

Evolution of Mobility Measures

These measures will be described in additional detail in the section on performance measures. However, it is important to recognize that this is the basis on which operations will be judged.

Define each of the measures. Point out that travel time and travel time reliability are the two measures that are rated highest by travelers.

Hours of delay is used for national reporting such as the TTI reports that indicate how many wasted hours people spend sitting in traffic annually. These measures are directly understood by the public and are far superior to the use of congestion.

Point out which measures relate to recurring congestion and which to non-recurring congestion

Definition of Measures – Travel Time

• Travel Time – The average time to traverse a section of roadway in a single direction
• Trip Travel Time – The average time required to travel from an origin to a destination including times for all modes of travel
• Travel Time Reliability – The additional time that must be added to a trip to ensure that travelers will arrive on time 95% of the time.

Definition of the Measures - Delay

• Delay – The difference between the travel time actually required to traverse a roadway segment and the unconstrained travel time
• Non-Recurring Delay – Vehicle delays in excess of recurring delay
• Recurring Delay –  Vehicle delays that are repeatable for the current time-of-day, day-of-week, and day-type

Perspective on Strategies

• Type of facility – arterial, freeway, corridor
• Problem addressed – recurring vs. non-recurring
• Impact – supply-side or demand-side
• Effectiveness – extent and intensity
• Life-cycle cost – implementation, operations and maintenance

There’’s a tendency to address the measures as a grab bag. If congestion is bad, add more measures. This is done without considering either their combined impact or the problem to be solved. Sometimes strategies are implemented without adequate budget to ensure their long term operations and maintenance.

The class has reviewed the strategies during the pre-study. During this section, we will examine them by trying to answer these questions. We’’ll also introduce some new strategies that might not have been covered by the pre-study material.

ITS Strategies – Traffic Signals

• Includes three variations
  • Better timing of time-of-day systems
  • Traffic-responsive systems
  • Adaptive systems
• Applicability
  • Type of facility – arterial, freeway or corridor?
  • Problem addressed - recurring or non-recurring?
  • Impact – supply-side or demand
  • Effectiveness – Widespread, high or low?

ITS Strategies – Ramp Metering

• Includes the following
  • Time-of-day systems
  • Traffic-responsive systems
  • Adaptive systems
  • Priority lanes
• Applicability
  • Type of facility – arterial, freeway or corridor?
  • Problem addressed - recurring or non-recurring?
  • Impact – supply-side or demand side?
  • Effectiveness – Widespread, high or low?

ITS Strategies – Incident Management

• Includes the following
  • Incident clearance
  • Traveler information
  • Traffic management
• Applicability
  • Type of facility – arterial, freeway or corridor?
  • Problem addressed - recurring or non-recurring?
  • Impact – supply-side or demand side?
  • Effectiveness – Widespread, high or low?

ITS Strategies – Traffic Operations Centers (TOCs)

• Includes:
  • Equipment Control
  • Incident Coordination
  • Communications
  • Monitoring
• Applicability
  • Type of facility – arterial, freeway or corridor?
  • Problem addressed - recurring or non-recurring?
  • Impact – supply, demand side or safety? Effectiveness – Widespread, high or low?

TS Strategies – Traveler Information

• Includes the following
  • Pre-trip planning
  • En-route information
  • In-vehicle information
• Applicability
  • Type of facility – arterial, freeway or corridor?
  • Problem addressed - recurring or non-recurring?
  • Impact – supply-side or demand side? Effectiveness – Widespread, high or low?

ITS Strategies – Lane and Speed Control

• Includes the following
  • Photo enforcement
  • Variable speed systems
  • Variable lane usage
• Applicability
  • Type of facility – arterial, freeway or corridor?
  • Problem addressed - recurring or non-recurring?
  • Impact – supply, demand or safety? Effectiveness – Widespread, high or low?

ITS Strategies – Electronic Payment Systems

• Includes the following
  • Tolling
  • Transit fare payment
  • Parking payment
• Applicability
  • Type of facility – arterial, freeway or corridor?
  • Problem addressed - recurring or non-recurring?
  • Impact – supply-side or demand side? Effectiveness – Widespread, high or low?

ITS Strategies – Commercial Vehicle Operations

• Includes the following
  • Weigh stations
  • Safety inspection
  • Border crossings
• Applicability
  • Type of facility – arterial, freeway or corridor?
  • Problem addressed - recurring or non-recurring?
  • Impact – supply-side or demand side?
  • Effectiveness – Widespread, high or low?

ITS Strategies – Transit Operations

• Includes the following
  • Bus preemption
  • Arrival information
  • Improved scheduling
• Applicability
  • Type of facility – arterial, freeway or corridor?
  • Problem addressed - recurring or non-recurring?
  • Impact – supply-side or demand side? Effectiveness – Widespread, high or low?

ITS Strategies – In-Vehicle Telematics

• Includes the following
  • Navigation
  • Safety & control
  • Information
• Applicability
  • Problem addressed - recurring or non-recurring, safety?
  • Impact – supply-side or demand side?
  • Effectiveness – Widespread, high or low?

Examples of ITS Applications Providing Congestion Relief

• Incident Management
• Work Zones
• Traveler Information
• Signal Timing
• Transit Management
• Toll Collection

Incident Management Programs

• Reduces incident duration by up to 65 percent
• Reduces crashes by up to 40 percent and secondary crashes by 30 to 50 percent
• Reduces fuel consumption by about 1.2 percent annually, saving thousands of gallons per major incident
• Motorist assistance patrols have a benefit-to-cost ratio of up to 36:1
• 32 percent of freeway miles are monitored by video to detect incidents, and 45 percent are served by motorist assistance patrols
• Traffic incident management on arterial streets is growing

ITS in Work Zones

• Temporary traffic management and information systems such as Dynamic Message Signs notify travelers of work zone activity and encourage use of alternative routes during periods of congestion
• Provides real-time information to motorists, reduces backups and traffic delays, and increases safety for workers and road users
• In California, an Automated Work Zone Information System
  • decreased weekday work zone traffic volumes up to 19 percent
  • increased the use of alternate routes by 10 to 15 percent

Traveler Information

• Enables travelers to alter time, mode, and route choices to avoid unexpected congestion
• Route-specific travel time information estimated to improve on-time performance of drivers by 5 to 13 percent
• Estimated to improve commuter on-time reliability by as much as 16 percent
• 511 systems being deployed across the country
  • Currently, 21 states have 511 systems in place
  • Surveys reveal 81 to 92 percent caller satisfaction
  • In Virginia, nearly half of 511 users adjust travel plans based on the information provided

Traffic Signal Systems

• Improved signal operations can
  • reduce traffic delay by 15 to 40 percent
  • reduce travel time by up to 25 percent
  • reduce stops by 10 to 40 percent
  • reduce fuel consumption by up to 10 percent
  • reduce harmful emissions by up to 22 percent
• Optimizing traffic signals can produce benefit-to-cost ratios as high as 40:1
• Adaptive signal control systems can reduce delay from 5 to 42 percent

Other ITS Applications Providing Congestion Relief

• transit management
  • computer aided dispatch systems (cad) that use automatic vehicle location (avl) can improve on-time bus performance by 9 to 23 percent
• toll collection
  • the new jersey turnpike authority reported that their ez pass system reduced toll station traffic delay by 85 percent
  • electronic toll collection saves new jersey turnpike travelers 2.1 million hours each year; reduces fuel wasted at toll stations