The National Household Travel Survey (NHTS) Add-On

Update

Huiwei Shen, FDOT Systems Planning

Florida’s Participation in the NHTS Add-On Program

Florida Model Task Force recommended participation in the National Household Travel Survey (NHTS) Add-On program

MPOAC agreed to use 2.6 million PL fund for 12,000 samples at $175 per sample plus $500K for data analysis

FDOT funded $350K for rural samples across the state

Sampling Plan Design Developed in consultation with FHWA NHTS

team Reviewed and approved by MTF Data

Committee Conforms to existing FDOT boundaries Meets urban and regional modeling needs Original plan based on 2000 Census

Households Revised plan guarantees that minimum

sample size per region is 1,200 Allows for meaningful comparisons

Sampling Plan Region 1 – Collier, Lee, Charlotte, Sarasota, and

Manatee (Census 2000 Households : 545,158 ) Region 2 – Duval, St. Johns, Clay, Nassau, and

Alachua (Census 2000 Households : 613,890 ) Region 3 – Leon, Gadsen, Wakulla, Walton,

Okaloosa, Santa Rosa, Escambia, and Bay (Census 2000 Households : 424,149 )

Sampling Plan Region 4 – Broward, Miami-Dade, Palm Beach,

Indian River, St. Lucie, and Martin (Census 2000 Households : 2,150,666 )

Region 5 – Orange, Osceola, Seminole, Lake, Sumter, Brevard, Volusia, and Marion (Census 2000 Households : 1,040,095 )

Region 7 – District 7 (except Citrus) and Polk (Census 2000 Households : 1,196,954 )

Region 8 – Rural counties not in the first six (Census 2000 Households : 370,209 )

Sampling Plan

    Sample SizeConfidence Interval

(95% CI)

Region

Number of Households Original Revised Original Revised

1

545,158 1,096 1,200 ± 3.0% ± 2.8%

2

613,890 1,234 1,234 ± 2.8% ± 2.8%

3

424,149 852 1,200 ± 3.4% ± 2.8%

4

2,150,666 4,322 4,116 ± 1.5% ± 1.5%

5

1,040,095 2,090 2,000 ± 2.1% ± 2.2%

7

1,196,954 2,406 2,250 ± 2.0% ± 2.1%

8

370,209 2,000 2,000 ± 2.2% ± 2.2%

Total

6,341,121

14,000

14,000 ± 0.8% ± 0.8%

Sampling PlanRegion Sample

SizeRegion 1 1,200

Region 2 1,224

Region 3 1,200

Region 4 4,116

Region 5 2,000

Region 7 2,250

Region 8 2,000

Sampling Plan MPO Sample Size Each MPO will be sampled such that at

least 80% of the sampled households from the MPO are included in the region sample

Why do this? Ensures smaller MPOs are sufficiently

sampled Makes data collection more cost effective

Rural Samples

FDOT District

Total Households

Sample Size

Confidence Interval (95% CL)

1 83,828 453 ± 4.6%

2 125,436 678 ± 3.8%

3 51,894 280 ± 5.9%

5 21,284 115 ± 9.2%

6 35,106 190 ± 7.1%

7 52,661 284 ± 5.8%

Rural Total

370,209 2,000 ± 2.2%

2001 NHTS Sample for Florida

Region Sample Size

Region 1 136

Region 2 158

Region 3 111

Region 4 401

Region 5 240

Region 7 295

Region 8 86

Additional Questions General Questionnaire Improvements

Elder Travel Transit Access Transportation Funding Preference

Additional Questions for Florida Residential Location Decision Seasonal Residents Transit Preference to Supplement

General Questionnaire

NHTS Status Awarded contract to Westat Completed Florida sampling plan Finalized Florida questionnaire Still need $$$ for the national samples Pretest December/January 2008 and

full data collection March 2008 Setup reporting system on internet