Evaluating Alternative Operations Strategies
to Improve Travel Time Reliability
Key SHRP2 L11 Deliverables
SHRP 2 L11 Team
Project Outcomes:
Kittelson & Associates:
John Zegeer, Principal Investigator
Marais Lombard, Assistant Principal Investigator
Research Team:
Sivaramakrishnan (Siva) Srinivasan
University of Florida Transportation Center
Mark Hallenbeck
Washington State Transportation Research Center
Randal Pozdena
Dr. Joseph L. Schofer
Northwestern University
Dr. Michael Myer
Georgia Institute of Technology
2) Effectiveness of Transportation Agencies
Add Logos
Danica Rhoades
Write Rhetoric
1) Generate profile of highway users & their need for travel time
reliability. Draft Completed
2) Assess the effectiveness of transportation agencies in
meeting reliability needs. Draft Completed
3) Develop goals & desired performance targets for travel time
4) Develop methods for estimating the value of travel time.
5) Identify trends likely to affect travel time reliability.
6) Develop three alternative scenarios for 2030, including an
assessment of their impact on travel time reliability as well as its
importance to users and operators.
7) Evaluate strategies for affecting travel time reliability.
8) Develop Concept of Operations for the present as well as for
three alternative futures.
The objectives of this task are to classify users into groups and
identify measures of travel-time reliability for each group.
SHRP2 Program:
SHRP2 is a targeted, short-term research program aimed at
addressing the challenges of moving people and goods
efficiently and safely. Within the overarching aims of the SHRP2
program, the Reliability Focus Area aims to develop approaches,
methods, and practices for improving the reliability of our
transportation system by reducing the adverse consequences of
nonrecurring congestion.
SHRP2 L11 Study Objectives:
To identify and evaluate strategies and tactics to satisfy the
travel time reliability requirements of users of the roadway
network – those engaged in both freight and person transport in
urban and rural areas.
Sources of Congestion
Single/Double Occupant, Transit, Multi-Modal
Work Flexibility
Urban/Rural, Distance, Facilities
Performance Targets
1) High-level, Qualitative Goals - based on important User
2) Quantitative Performance Measures for Each Goal based on stakeholder needs & requirements, as well as
existing conditions evaluation.
• Buffer Index - Difference between 95th percentile travel time
and average travel time, normalized by average travel time;
• Planning Time - The 95th Percentile Travel Time Index;
• Percent trips with space mean speeds <= 50 mph; and
• Percent trips (section or O/D pair) w space mean speeds
<=30 mph.
User Surveys & Discussions
Freight Movers
Operational Characteristics
Fleet Size:
Small Fleet (Single Driver)
Medium/Large Fleet
Freight Characteristics:
Part of Supply-Chain
Time of Day
Possibilities for Adverse
Identify a comprehensive set of trends regarding internal and
external macro-level factors that affect travel time reliability in
the present and the future.
• Identify comprehensive set of trends (internal and external)
• Screen potential trends and assess their relationship to nonrecurring congestion and reliability
• Develop Working Paper
Assess how these trends are influenced by factors internal
and external to the Transportation Agency
6) Three Alternative Futures for 2030
Identify apparent and potential trends that may:
• Influence the transportation system & demands for it;
• Frequency of non-recurring congestion;
• Priorities placed on mitigation such congestion;
• Technologies that may facilitate effective responses;
• Broader social, environmental, and political context within
which future transportation system will be managed.
Changes & Enhancements in
Supporting Technologies
Global Climate Change
Three Alternative
Futures for 2030
Increases in Energy Costs
Increasing & Aging Population
7) Strategies and Tactics
List and discuss no-, low-, and high-tech strategies
and tactics that can improve travel time reliability
for the following:
Long-Haul or Urban only
Point-point vs multiple
Freeway/Arterial Usage
Pricing Facilities
Border Crossings
Exclusive Lanes
3) Goals for Improving Reliability
Time of Day, Possibility of Adverse Weather
Travel Context
• Strategies Implementable by Agencies.
• Ability of Agencies to Implement Strategies under current ,
resource-constrained conditions.
• Qualitative Measurements to Rank Effectiveness of
Existing Measures Used
Children at Home Routine & Temporally Constrained
User Requirements
Assess Reliability for 1) the Network as well as 2) entire
Transportation System.
1) Current & Future User Needs
About SHRP 2 L11 Travel Time Reliability Research
Evaluate the current effectiveness of transportation agencies,
incident responders, and other stakeholders in meeting user
(passenger & freight) requirements.
5) Trends that Affect Reliability
4) Economic Benefits
Develop & carry out an approach for imputing the dollar value of
incremental improvements in travel time reliability to enable
evaluation of alternative operations strategies aimed at reducing
non-recurring congestion.
Evaluate Various Settings for measuring
the value of reliability:
• Users/ Markets;
• Facilities – freeway/arterial;
• Levels of Ambient Congestion;
• Types & Sources of Congestion
(1) those currently in use in the U.S. and other countries;
(2) emerging strategies and tactics;
(3) new and innovative strategies and tactics that could
appear by the more distant future, 2030.
8) Operations Concept for Present and Future
Develop a Baseline Concept of Operations (Con Ops) for the
present. Also, develop three distinct Concepts of Operations
framed by different futures for the year 2030.
Con Ops Document will Answer the Following:
• What - known elements & high-level capabilities of system;
• Where - geographical & physical extents of system;
• When - time-sequence of activities that will be performed;
• How - resources needed to design, build, operate &
maintain system;
• Who - stakeholders involved with system & their respective
responsibilities; and
• Why - justification for system, identifying what corridor
currently lacks and what system will provide.