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

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


• 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 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


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

• Premium

• Bus

• Combination

– Separate networks used for each sub-mode


• 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


• 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


• Baseline Alternative– Bus Line through the corridor

• Operated in mixed traffic

• Times dependent on congestion

• Build Alternative– Commuter Rail Line

• Fixed guideway

• 5 stations


• Model Runs– Build alternative

• higher mode shares

• improved travel times

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

project area


• 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


• 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


• 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

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

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