Income-Based Work Trip Stratification within the Puget Sound Regional Council Travel Model Framework

20th InternationalEmme Users’ Conference

Montreal, QuebecThursday, October 19th, 2006

Chris JohnsonPuget Sound Regional Council

Puget Sound Regional CouncilSeattle, Washington USA

Membership

• King, Kitsap, Pierce and Snohomish Counties

• 70 cities

• 4 Ports

• Tribes

• State agencies

• 7 Transit agencies

• Associate members

3.4 million residents

• (+1.7 million by 2040)

1.9 million jobs

• (+1.2 million by 2040)

King

Kitsap

Pierce

Snohomish

Traditional 4-Step (Trip Based)

938 Zone/19,000 Link Network

Trip Generation – Cross Classification

Trip Distribution – Gravity

Mode Choice – Multinomial/Nested Logit, Non-Motorized Modes

Time-of-Day (AM Peak Period, Mid-Day, PM Peak Period, Evening, Night)

Assignment – Multi-Class (11), Generalized Cost

Full Documentation – www.psrc.org

Overview – Basic Model Structure

Model Process

U.S. and Washington Economies

Prior Years Households and

Employment Location

Zonal Data

Land Use Allocation Models

DRAM/EMPAL

Legend:

Input Files Models/Processes Data Output Files

Output, Jobs, and Personal Income by 30 Industrial

Sectors

HighwayNetworks

Households by 4 Income Groups

and Employment by 5 Categories

Households by Workers, Income, Household Size,

and Vehicles Available

Trips by 7 Purposes (HBW

by 4 income groups)

Economic Forecasting Model STEP

Vehicle Availability

Model

Trip Generation

Model

Additional Zonal and Cost Data

TransitNetworks

Trip Distribution

Model

Mode ChoiceModel

Time of Day Model

Trip Tables by 7Trip Purposes

(HBW by 4 income groups)

Trip Tables by 5 Trip

Purposes and 7 modes

Trip Tables for 5 Time Periods and 4 Purposes (HBW by 4 income groups

4-County Region

Forecast Analysis

Zones

Traffic Analysis

Zones

Trip Assignment

Model

Highway and Transit

Volumes and Travel Times

TruckModel

Land Use and Travel Demand Forecasting Process Trip Purposes (10):

Home-Based• Work (4)

• Other

• Shopping

• School (K – 12)

• College (Households & Dormitories)

Non Home-Based• Work/Other

• Other/Other

Home-Based Work

Income Stratification within:

• Trip Generation

• Trip Distribution

Approach/Structure/Processes

Results

Observations

Final Thoughts

Today’s Focus

Trip Purpose Breakdown

Trip Purpose Productions/Attractions Percent Total

Home-Based WorkIncome less than $25,000 146,924 1%Income $25,000-$45,000 345,518 3%Income $45,000-$75,000 640,106 5%Income more than $75,000 851,933 7%

Home-Based Work - Total 1,984,481 16%College 98,030 1%Home-Based School 883,724 7%Home-Based Shop 1,427,492 11%Home-Based Other 4,418,377 35%Non-Home-Based Work 1,129,434 9%Non-Home-Based Other 2,774,412 22%

Total Person Trips 12,715,950 100%

Built-In Structure not being used – Easily Implemented

Capture Trip-Making Differences among the Different Income Groups

Achieve a Better Match between Household and Job Locations

Position Model for Evaluation/Analysis of Tolling/Pricing Policies

Rationale – Income Stratification

Less than $10,000

$10,000 – $14,999

$15,000 – $24,999

$25,000 – $34,999

$35,000 – $44,999

$45,000 – $54,999

$55,000 – $74,999

$75,000 or More

1999 HH Travel SurveyHH Income Categorization

Stand Alone

Stand Alone

Combine

Combine

Combine

Combine

Income Class Stratification:• Less than $15,000 HH Income

• $15,000 – $24,999 HH Income

• $25,000 - $44,999 HH Income

• $45,000 - $74,999 HH Income

• $75,000 or more HH Income

Categorization from 1999 HH Travel Survey

Sum Productions in Bottom Ranges before Distribution

• Single Range – Less than $24,999 HH Income

Home-Based WorkTrip Production Rates

Less than $16,000 HH Income

$16,000 – $26,599 HH Income

$26,600 – $47,899 HH Income

$47,900 – $79,799 HH Income

$79,800 or more HH Income

$CDN$

2000 Median HH Income:

• King – $53,000

• Kitsap – $47,000

• Pierce – $45,000

• Snohomish – $53,000

Regional HH Income Distribution:

• Less than $24,999 = 20.6% of Households

• More than $75,000 = 29.2% of Households

HH Income Data – 2000 Census

Home-Based WorkTrip Production Rates

65 Unique Classifications

HH Size/Workers in HH/HH Income Range

Home-Based WorkTrip Attraction Rates

Expedient/Straightforward

Based on Analysis of 2000 Census Data

HH Incomes of Workers by Industry

Home-Based WorkTrip Attraction Rates

Quick Recap

Calculate HB Work Productions for 5 Income Classes

Sum Lowest 2 Classes (Less than $25,000)

Calculate HB Work Attractions for 4 Income Classes

Distribute HB Work Trips for 4 Income Classes

• Gravity

• Composite Impedances (log sums)

Results – Distribution

Average Trip Duration and Length by Purpose

Results – Distribution

Intrazonal Trips and Travel Times by Trip Purpose

District-District Comparisons

District-District ComparisonIncome Class 1 (Obs. – Est.)

District 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Total1 14% 4% 4% -1% -4% -7% -1% -2% -1% -3% 0% -1% 0% 0% 0% 0% 0% 0% -5% 0%2 7% 28% 4% -4% -11% -11% -1% -4% -2% -3% 0% -1% 0% 0% 0% 0% 0% 0% 0% 0%3 4% 1% 0% 12% 3% -10% -1% -3% -1% -4% -3% -1% 0% 0% 0% 0% 0% 0% 5% 0%4 0% -1% 0% -6% -6% 6% 10% -7% -3% 0% -1% 10% -1% 0% 0% 0% 0% 0% 0% 0%5 0% 5% 0% 13% 3% 5% 0% -13% -4% -5% -2% -1% -1% 0% 0% 0% 0% 0% 0% 0%6 0% 0% 0% 5% 8% 0% 0% -10% -4% -1% 5% 1% -2% 0% 0% 0% 0% 0% 0% 0%7 0% 0% 0% 0% -1% 50% -23% -7% -15% -2% -1% -1% 0% 0% 0% 0% 0% 0% 0% 0%8 0% 0% 0% 0% 0% 33% 65% -72% -22% -1% -1% -1% 0% 0% 0% 0% 0% 0% 0% 0%9 0% 0% 0% 0% 0% 0% -3% -9% 6% 6% 0% -1% -1% -1% 4% -1% 0% 0% 0% 0%

10 0% 0% 0% 0% 7% -5% -1% -2% -2% 2% -12% 9% 4% 0% 0% 0% 0% 0% 0% 0%11 0% 0% 0% 0% 0% 0% 0% 0% 0% 20% -12% -7% 0% 0% 0% 0% 0% 0% 0% 0%12 0% 0% 0% 0% 0% 0% 0% -1% 5% 0% -15% -3% 13% 0% 0% 0% 0% 0% 0% 0%13 0% 0% 0% 0% 0% 1% 0% 0% -1% -3% 15% -1% -18% 0% 3% 0% 5% 0% 0% 0%14 0% 0% 0% 0% 0% 0% 0% -4% -15% 16% 27% -8% -30% 13% 2% -2% 0% 0% 0% 0%15 0% 0% 0% 0% 0% 0% 0% -3% 15% -1% 7% -3% 14% 1% -30% -7% 8% 0% 0% 0%16 0% 0% 0% 0% 0% 0% -1% -7% -21% 0% 0% -1% 5% -2% 15% -10% 13% 9% 0% 0%17 0% 0% 0% 0% 0% 0% 0% 3% 8% 0% 7% 0% -1% 6% -6% -6% -21% 12% 0% 0%18 0% 0% 0% 0% 0% 0% 0% -2% -11% 0% 4% 0% -1% 8% 11% -3% 16% -20% 0% 0%19 0% 0% 0% 0% 0% 0% 0% 0% 0% 3% -17% -1% 0% 0% 0% 0% 0% 0% 15% 0%

District-District ComparisonIncome Class 2 (Obs. – Est.)

District 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Total1 11% -3% 6% -1% -1% -4% 0% -1% 3% -2% -2% -1% -1% 0% 0% 0% 0% 0% -3% 0%2 2% 14% 3% -9% -7% 4% -1% -2% -1% -2% 2% -1% -1% 0% 0% 0% 0% 0% 0% 0%3 4% 0% 8% -7% 0% 0% -1% -2% -1% -3% 0% -1% 1% 0% 0% 0% 0% 0% 2% 0%4 -1% -3% 3% 18% -11% -11% 5% -3% -1% 0% -2% 1% 0% 0% 4% 0% 0% 0% 0% 0%5 0% 0% 0% -1% 11% -11% 2% -7% 2% 1% 5% 0% -1% 0% 0% 0% 0% 0% 0% 0%6 0% 1% 0% -1% 3% -6% -1% -3% 3% 1% 2% 0% 1% 0% 0% 0% 0% 0% 0% 0%7 0% 4% 0% -1% 3% -3% -2% -6% -7% -1% 8% -3% 1% 0% 4% 0% 4% 0% 0% 0%8 0% 0% 0% 0% -1% 1% -4% 7% -14% -5% 0% 13% -2% 0% 0% 4% 0% 0% 0% 0%9 0% 0% 0% 0% 0% 0% -2% -8% 1% -2% 3% 2% 0% 0% -2% 5% 5% 0% 0% 0%

10 0% 0% 0% 0% -1% -4% -1% -6% 1% 3% 1% 8% 1% 0% 0% 0% 0% 0% 0% 0%11 0% 0% 0% 0% 0% 0% 0% 0% 33% -1% -21% -10% 0% 0% 0% 0% 0% 0% 0% 0%12 0% 0% 0% 0% 0% 4% 0% 1% 6% 7% -13% -7% 4% 0% 0% 0% 0% 0% 0% 0%13 0% 0% 0% 0% 0% 0% 0% -4% -3% 5% 1% -5% 1% -1% 1% 1% 2% 1% 0% 0%14 1% 0% 0% 0% 3% -2% -1% 3% -5% 0% -3% -4% -1% 6% -2% 6% -1% 0% 0% 0%15 0% 0% 0% 0% 0% -1% -1% -2% -5% -1% 3% -4% -6% 0% 9% -6% 15% -1% 0% 0%16 0% 0% 0% 0% 0% -1% -1% -3% 2% -2% 0% 11% -7% 4% -8% -13% 3% 15% 0% 0%17 0% 1% 0% 0% 0% 2% 0% 3% 6% 0% 3% 4% -2% -2% 4% -1% -16% -2% 0% 0%18 0% 0% 0% 0% 0% 0% -1% -4% -2% 0% 1% 1% 1% -1% 0% -3% 3% 6% 0% 0%19 3% 0% 0% 0% 0% 0% 0% 0% 0% 1% -18% -1% 1% 0% 0% 0% 1% 0% 13% 0%

District-District ComparisonIncome Class 3 (Obs. – Est.)

District 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Total1 0% -5% 7% 4% -1% -2% 0% -1% 0% 2% 3% 1% -1% 0% 0% 0% 0% 0% -6% 0%2 -1% 4% 2% 1% -3% -2% -1% 0% 0% 1% 2% -1% 0% 0% 0% 0% 0% 0% 0% 0%3 -2% 7% 9% -5% -4% -1% -1% 0% -1% -3% 2% 0% -1% 0% 0% 0% 0% 0% -1% 0%4 -1% -5% -1% 7% 4% -5% -1% -2% -1% 1% 7% -1% -1% 0% 1% 0% 0% 0% 0% 0%5 0% 0% 0% 2% 8% -7% -2% -2% 0% 0% 3% -1% -1% 0% 0% 2% 0% 0% 0% 0%6 0% 1% 1% -1% 7% -1% 0% -3% -4% -5% 1% 4% -4% 0% 0% 1% 2% 0% 0% 0%7 0% 0% 0% -1% -1% -2% 15% -2% -9% -5% 9% -5% -3% 0% -1% 3% 3% 0% 0% 0%8 0% 0% 0% 1% -1% 3% 0% -4% -5% 1% 6% -1% 2% 0% -1% 1% 0% 0% 0% 0%9 0% 0% 0% 0% -1% 3% -2% -1% -3% 2% 3% 1% -4% -1% -2% 0% 4% -1% 0% 0%

10 2% 2% 2% -1% 2% 2% -1% -3% -2% 7% -10% 1% -2% 0% 0% 0% 2% 0% -1% 0%11 0% 0% 0% 0% 0% 0% 0% 0% 19% -1% -53% 38% -1% 0% 0% 0% 0% 0% -1% 0%12 0% 0% 0% 1% 0% 2% 0% 6% 2% -1% -6% -10% 6% 0% 0% 1% 1% 0% -1% 0%13 0% 0% 0% 0% 0% 2% 1% 0% 2% -3% -7% -1% 1% 0% 3% 1% 1% 0% -1% 0%14 0% 0% 0% 0% -1% -2% -1% -4% 0% -3% 5% -1% -3% 4% 1% -3% 5% 1% 0% 0%15 0% 0% 0% 0% 0% 2% 3% -3% 0% 0% 2% 1% -7% -2% 0% 1% 2% 2% 0% 0%16 0% 0% 0% 1% 0% -1% -2% -5% -9% -3% 0% -2% 0% -1% 1% 6% 19% -3% 0% 0%17 0% 0% 0% 0% 0% 1% 1% -3% -2% 3% 1% -2% 0% -2% 3% 4% -7% 1% 0% 0%18 0% 0% 0% 0% 0% 0% -1% -2% -1% -1% 2% -1% 0% -1% 0% 0% 9% -4% 0% 0%19 1% 0% -1% 2% 1% 0% 0% 0% 0% -1% -13% -2% 0% 0% 1% 0% 2% 0% 13% 0%

District-District ComparisonIncome Class 4 (Obs. – Est.)

District 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Total1 3% 0% 4% 3% -2% 2% 0% 0% 0% -1% 1% 1% 0% 0% 2% 0% 0% 0% -11% 0%2 -9% 6% 0% 4% -3% -1% 0% 0% 5% 0% 1% -1% 0% 0% 0% 0% 1% 0% -1% 0%3 -8% -8% 18% -9% 2% 0% 0% -1% 0% 1% 3% 3% 0% 0% 0% 0% 0% 0% 0% 0%4 -5% -3% 3% 7% 0% -12% -1% 5% -1% 0% 8% -2% -1% 0% 2% 3% 0% 0% -1% 0%5 0% -5% -4% -1% 3% 4% 0% 2% 4% -1% 0% -2% 1% 0% 0% 0% 0% 0% 0% 0%6 -1% -1% -2% -1% 1% 3% -2% 6% 4% 1% -5% -4% 3% 0% -1% 0% 0% 0% 0% 0%7 1% -1% -1% -1% -5% -4% 13% 3% 7% -6% 0% -5% -4% 0% 2% -1% 3% 0% 0% 0%8 0% 0% 1% 0% 1% -5% 4% 14% -5% -5% -2% 0% -2% 0% -1% 2% -1% 0% 0% 0%9 0% 0% 0% 0% -2% -2% -3% 0% 11% -2% 9% -3% -3% -1% -3% 1% 0% -1% 0% 0%

10 -1% -1% -1% 1% 0% -9% -1% 1% 6% 6% 11% -6% -3% 0% -1% 0% 0% 0% -2% 0%11 0% 0% 0% 0% 0% -1% 0% 14% 0% -2% -5% -1% -1% 0% 0% 0% 0% 0% -3% 0%12 0% 0% 1% 0% -1% -1% -1% 1% 8% -2% -7% -5% 5% 2% -1% 2% 0% 0% -1% 0%13 0% 0% 2% 0% -1% -2% 0% 2% -1% -5% 12% -3% -7% 0% 0% 1% 4% 0% -1% 0%14 0% 0% 0% 1% -1% -4% -1% -3% -2% -1% 15% 1% 5% 0% -7% -1% -1% -1% 0% 0%15 0% 0% 0% 0% 1% -3% -1% -3% -6% -2% 6% 5% -3% -1% 7% -1% 1% 0% 0% 0%16 0% 0% 0% 0% 0% 3% -1% 3% -9% -2% 4% 0% 5% -3% -9% 0% 11% -1% 0% 0%17 0% 0% 0% 0% 0% -2% 0% 1% -3% 5% -1% 1% -1% -2% -4% -5% 15% -3% 0% 0%18 0% 0% 0% 0% -1% -1% -1% -4% 0% -1% -1% -3% -2% -1% -1% 3% 9% 4% 0% 0%19 -3% 0% -2% 1% 0% 1% 0% 2% 0% 6% 9% 0% 1% 0% 0% 0% 0% 0% -13% 0%

District-District ComparisonAll Income Classes (Obs. – Est.)

District 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Total1 6% -2% 5% 2% -1% -1% 0% -1% 1% -1% 1% 0% 0% 0% 0% 0% 0% 0% -7% 0%2 -3% 8% 2% 0% -4% -1% -1% -1% 1% -1% 2% -1% 0% 0% 0% 0% 0% 0% -1% 0%3 -1% 0% 10% -4% 0% -2% -1% -1% 0% -2% 1% 0% 0% 0% 0% 0% 0% 0% 1% 0%4 -2% -4% 0% 9% -2% -7% 1% -1% -1% 1% 4% 0% -1% 0% 2% 1% 0% 0% 0% 0%5 0% -2% -1% 1% 7% -2% 0% -2% 2% -1% 1% -1% 0% 0% 0% 0% 0% 0% 0% 0%6 0% 0% -1% 0% 4% -1% -1% -1% 1% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0%7 1% 0% -1% -1% -3% -2% 11% 0% 1% -5% 3% -5% -3% 0% 1% 0% 3% 0% 0% 0%8 0% 0% 1% 0% 0% -2% 3% 6% -6% -3% 1% 1% 0% 0% -1% 2% -1% 0% 0% 0%9 0% 0% 0% 0% -1% -1% -2% -2% 6% 0% 6% -1% -3% -1% -2% 1% 2% -1% 0% 0%

10 0% 0% 0% 0% 1% -5% -1% -2% 1% 7% -1% 2% -1% 0% -1% 0% 0% 0% -1% 0%11 0% 0% 0% 0% 0% 0% 0% 4% 13% 2% -26% 9% -1% 0% 0% 0% 0% 0% -1% 0%12 0% 0% 0% 0% 0% 1% 0% 2% 5% 0% -9% -6% 6% 0% 0% 1% 0% 0% -1% 0%13 0% 0% 1% 0% 0% 0% 0% 0% 0% -2% 3% -3% -3% 0% 1% 1% 3% 0% -1% 0%14 0% 0% 0% 0% 0% -3% -1% -2% -3% -1% 9% -1% 0% 3% -3% 0% 1% 0% 0% 0%15 0% 0% 0% 0% 0% -1% 0% -3% -2% -1% 4% 1% -3% -1% 3% -2% 5% 1% 0% 0%16 0% 0% 0% 0% 0% 1% -1% -1% -8% -2% 2% 0% 2% -1% -4% 0% 13% 1% 0% 0%17 0% 0% 0% 0% 0% 0% 0% 0% 1% 3% 2% 0% -1% -1% 0% -1% -3% 0% 0% 0%18 0% 0% 0% 0% 0% 0% -1% -3% -1% -1% 1% -1% -1% -1% 0% 0% 8% 1% 0% 0%19 0% 0% -1% 1% 0% 0% 0% 1% 0% 2% -6% -1% 0% 0% 0% 0% 1% 0% 4% 0%

Results: District-District Validation

Most Trips, Regardless of Income Class are Intra-District

Some Discrepancies (both Intra- and Inter-District) Exist and Should be Further Investigated

Overall (All Income Classes) District-District Comparison Appears Acceptable

HB Work Trip Production Rates Increase as HH Income Increases

Observations

ObservationsHome-Based Work Trip Production Rates

Trip Rate Differences Less Evident on Attraction Side

• Government – Highest Low Income, Lowest High Income

• Manufacturing – Lowest Low Income, Highest High Income

• Retail – Percent of High Income HHs is Surprising

Observations

ObservationsHH Income Profiles of Workers by Industry

Average Trip Lengths Increase as HH Income Increases

Observations

Observations

Average Trip Duration and Length by Purpose

Observations

Intrazonal Trips and Travel Times by Trip Purpose

HB Work Trip Production Rates Increase as HH Income Increases

Trip Rate Differences Less Evident on Attraction Side• Government – Highest Low Income, Lowest High Income

• Manufacturing – Lowest Low Income, Highest High Income

• Retail – Percent of High Income HHs is Surprising

Average Trip Lengths Increase as HH Income Increases

Valid Distribution Model

Observations

Zone Size

• Smaller Zones Would Allow for Easier Isolation of Higher/Lower Income Neighborhoods

• Or Does Zone Size Matter?

More Refined Income Brackets

• $75,000+ Probably Too Low for the Highest Income Range− $75,000 – $100,000 = 13.4% (2000 Census)− More than $100,000 = 15.8% (2000 Census)

• 2006 HH Survey – Category with $100,000+

Why the Trip Production Rate Differences? Would Tours Show Same Differences?

Will these Production Rates Stay Constant Over Time – 2040? Will these Income Profiles by Industry Stay Constant Over Time – 2040?

Occupation vs. Industry Data – Occupation-based Data May Be More Reflective of Income

• (I.e., Management vs. Sales vs. Service vs. Retail)

More Geographic Analysis

Thinking Out Loud…

Merci!Questions?

Chris JohnsonPuget Sound Regional Council1011 Western Avenue, Suite 500Seattle, WA 98104tel 206 389 2876fax 206 587 4825cjohnson@psrc.orgwww.psrc.org