Calculating Transportation System User Benefits:Interface Challenges between EMME/2 and Summit

Principle Author:

Jennifer JohnSenior Transportation Planner

Portland Metro Planning Department600 Northeast Grand AvenuePortland, Oregon 97232-2736

For Presentation at the 17th International EMME/2 Users Group Conference

Calgary, Alberta, Canada October 22-24, 2003

• Regional Government

• Chartered by voters in the Tri-County area– 1.3 million people– 3 Counties– 24 Cities

Metro

• Responsible for– Open Spaces & Parks– Landuse & Transportation Planning– Garbage Disposal and Recycling

• Owns & Operates– Oregon Zoo– Oregon Convention Center

Metro

Portland Portland

Light Rail TransitLight Rail Transit

ExperienceExperience

“Summit” Software• Federal Transit Administration (FTA)

requirement for all New Starts Projects

• Calculates “User Benefits”– Travel Time Savings

• Baseline and Build Alternatives

Summit Software (continued)

• For the Analyst– helpful in designing transportation systems– assessing how well projects perform– lead to improvements in modeling process

• For FTA– provides consistent reporting measures– “level playing field” – “Transparency”

Integrating Summit and Metro’s Model

• Building the connection

• Challenges

• Project Experiences

Portland Demand Model

• Traditional Four-Step Process

• Updates– response to complex questions

• FTA

• Regional Policy Makers

• local jurisdictions

• consultants

Portland Demand Model

• Old Model Included Post-Mode Choice Process– Model Estimation used information from a

survey that was conducted prior to the opening of the first light rail line in the region.

– A New Survey was conducted in the light rail corridor after the line opened

• New Survey showed difference in walk vs.. park & ride access to light rail

Portland Demand Model

• Portland Metro worked with FTA– Developed Post-mode choice factor

• increased proportion of park & ride access to light rail system

• Post-mode choice factor did not work with Summit Software– New Model sets in Portland do not include any

post processing of mode split information

Summit Requirements

• Total Person Trips

• Total Motorized Person Trips

– all trips that are used in the mode choice model

• Fraction of person trips that have walk-to-transit path

• Transit share of person trips that have a walk-to-transit path

• Fraction of person trips that have a drive-to-transit path

• Transit share of person trips that have a drive-to-transit path

Summit File Format

• Previously listed information must be formatted for input to Summit.– If model is run in EMME/2 module 3.14 will

output the information properly– EMME/2 output needs to be converted to

Binary format

Summit File Format

Required Model Information

• Information pulled out of the model for each trip purpose by market segment– market segmentation

• auto ownership

• income groups

Metro Model Trip Purposes

• Home-Based Work• Home-Based Shop• Home-Based Recreation• Home-Based Other• Non-Home-Based Work• Non-Home-Based Non-Work• College• School

Metro Model Trip Modes

• Drive Alone

• Drive with Passenger

• Passenger

• Auto Access Transit (Park & Ride)

• Walk Access transit

• Bike

• Walk

Walk Access Transit

• Sub-modes– Premium Service

• typically fixed-guideway

• premium bus service can also be included– BRT (Bus Rapid Transit)

– Bus Service– Combination

Market Segmentation In the Model

• Auto Ownership, Income Groups & Time of Day– Home-based Work– Home-based Shop– Home-based Recreation– Home-based Other

• Remaining purposes use only Income and Time of Day

Using Metro Information in the Summit Software

• Summit configured for 8 market segments

• Metro model – 18 segments for four of the trip purposes– 6 segments for remaining purposes

• Summit set up to easily work with conventional model sets

• Metro model not conventional!

Using Metro Information in the Summit Software

• Four purposes with large market segmentation– To fit into Summit three separate files with 6

categories are saved– Summit is run three times for each of these

purposes– Output from each run added together to get

hours of transportation system user benefit

Summit Output Information

• For each trip purpose and market segment– Row and Column Summaries for every zone in

network• Row values indicate benefits from zones

• Column values indicate benefits to zones

– Benefits may be positive or negative

Using Summit Outputs

• Can be used with a variety of available software packages– EMME/2– Excel– ArcView

Summit Output File

Use with EMME/2Format into mo or md and batch into bank

Use with Excel

Use with ArcView

Travel Times and the Summit Software

• Auto and Transit Times evaluated

• User benefit = time savings between alternatives

• Travel times for input to demand model are created in EMME/2– am peak , midday time periods

– auto and transit

– multiple iterations in auto assignment to achieve desirable state of equilibrium

Travel Times and the Summit Software

• Transit Times– Assignments run for each transit sub-mode

• Premium

• Bus

• Combination

– Separate networks used for each sub-mode

Travel Times and the Summit Software

• Single trip table used as starting point

• Alternatives iterated through model– Allows mode share changes to influence travel

times as they are fed back through the model

Travel Times and the Summit Software

• Auto times influence transit path choices– When evaluating alternatives it is helpful to

check differences prior to running model

• Are differences the result of system design?

• Are differences the result of path choice shifting from small changes in the underlying auto assignment?

Portland Project ExperienceWashington County Commuter Rail

Portland Project ExperienceWashington County Commuter Rail

• Baseline Alternative– Bus Line through the corridor

• Operated in mixed traffic

• Times dependent on congestion

• Build Alternative– Commuter Rail Line

• Fixed guideway

• 5 stations

Portland Project ExperienceWashington County Commuter Rail

• Model Runs– Build alternative

• higher mode shares

• improved travel times

• Summit Output– Overall negative benefits– High positive and negative benefits outside

project area

Portland Project ExperienceWashington County Commuter Rail

Portland Project ExperienceWashington County Commuter Rail

Portland Project ExperienceWashington County Commuter Rail

• What did we do to move from initial run to final run?– Summit produces both auto and transit benefit

• Isolated each piece to evaluate them

– Compared travel times from Build and Baseline in emme2bank

• equilibrium assignment issues

• time differences negligible but were magnified in Summit

Portland Project ExperienceWashington County Commuter Rail

• What did we do? (continued)– FTA only evaluating transit benefits

• issues with auto benefits and equilibrium assignments

– Decided to use common trip tables for Baseline and Build Alternative

• While this limits benefit to project as a result of improved travel times to auto it

Portland Project ExperienceWashington County Commuter Rail

• Insights into some remaining zones with negative numbers– Total times vs. weighted components

• Setting up matrix calculations in emme2bank helps identify issues– network definitions– skim procedures

Summary

• Many Issues

• Lessons Learned– Shift in how projects are evaluated

• moving to more precise level of analysis

• level of complexity

– Use available tools and resources to be as familiar as possible with networks, inputs and procedures in model runs