2001 National Household Travel Survey Kentucky Add-on Ben Pierce Presentation By

Acknowledgements MORPACE, International FHWA, Office of Highway Policy Information

Page 3 Kentucky Traffic Model Users Group: Travel Survey Workshop NHTS Presentation Outline  What is the NHTS?  What is the NHTS Add-on Program?  Kentucky’s Involvement  Overview of Survey Methodology  Review of Collected Data  Summary of Participation  Selected Results in Kentucky

Page 4 Kentucky Traffic Model Users Group: Travel Survey Workshop NHTS What is the NHTS?  Travel survey that collects information on travel from a national sample of the civilian, non-institutionalized population of the United States  Conducted roughly every five years since 1969, last conducted in 1995  Traditionally collected travel information for one day of travel; in 2001 also collected information on long-distance travel (prior 28 days)  Data are used to produce national estimates of travel and investigate topics in transportation safety, congestion, mobility of various population groups, the relationship of personal travel to economic productivity, the impact of travel on the human and natural environment, etc.

Page 5 Kentucky Traffic Model Users Group: Travel Survey Workshop NHTS What is the NHTS Add-on Program?  ~26,000 households included in the national sample  National sample designed for national estimates – not enough for reliable state and local estimates  FHWA offered states and local municipalities the opportunity to purchase additional samples specific to their area  In 2001, additional samples were purchased by nine state and local municipalities, adding an additional ~66,000 households  These additional samples are referred to as NHTS Add-ons

Page 6 Kentucky Traffic Model Users Group: Travel Survey Workshop NHTS Kentucky’s Involvement  Kentucky participated as a 2001 NHTS Add-on Purchasing 1,100 households in Kentucky County Number of Purchased Households Number of Completed Households Carter150 Edmonson Pulaski Scott Total1,1001,154

Page 7 Kentucky Traffic Model Users Group: Travel Survey Workshop NHTS Overview of Survey Methods  Computer Assisted Telephone Interview (CATI)  Samples (households) are selected based upon telephone numbers using list-assisted, random digit dialing methods  Two stage survey –Household interview –Person-level interview (Extended Interview)

Page 8 Kentucky Traffic Model Users Group: Travel Survey Workshop NHTS Overview of Survey Methods (cont.) Pre-Contact Letter Household CATI Interview Travel Diaries Telephone Reminder Calls Extended CATI Interviews Signed by Terri Giltner, Exec. Dir. Office of Public Affairs, KYTC $2 incentive First Class mail Up to 19 calls Household characteristics Household demographics Respondent  18 Diaries + Memory Aids $2 per person incentive Priority Mail Travel Day is days after Household Interview Day before Travel Day Message left on answering machine 3 busy signals before no- contact Within 6 days after Travel Day Personal travel characteristics Trip information Proxy reporting allowed

Page 9 Kentucky Traffic Model Users Group: Travel Survey Workshop NHTS Overview of Survey Methods (cont.) Things to Note:  NHTS employs a “memory jogger” style diary, and is a trip-based survey  Information on trips is collected by first “rostering” all trips for an individual, then going back and asking detailed information for each trip  Trips are 1-way; origin-to-destination  Proxies are permitted, but only under certain conditions

Page 10 Kentucky Traffic Model Users Group: Travel Survey Workshop NHTS

Page 11 Kentucky Traffic Model Users Group: Travel Survey Workshop NHTS Three Methodological Differences from NHTS National Methodology 1.National Sample used $5 incentive vs. $2 in Kentucky Add-on 2.National Sample included questions on long- distance travel, Kentucky Add-on did not 3.Definition of a “completed” household differed: National Sample = At least 50% of household members aged 18 years or older needed to complete the extended (person-level) interview Kentucky Add-on = All members of the household needed to complete an extended (person-level) interview

Page 12 Kentucky Traffic Model Users Group: Travel Survey Workshop NHTS Data Collected FOR EACH HOUSEHOLD: Number of people Number of drivers Number of workers Number of vehicles Income Housing type Owned or rented Number of cell phones Number of other phones Race of reference person Hispanic status of reference person Tract & block group characteristic FOR EACH PERSON: Age Gender Relation to reference person Driver status Worker status/Primary activity Internet use Travel disability Effect of disability on mobility Highest grade completed Immigrant status Views on transportation Annual miles driven Incidence of public transit use in past two months Incidence of walk and bike trips in past week

Page 13 Kentucky Traffic Model Users Group: Travel Survey Workshop NHTS Data Collected (cont.) FOR EACH WORKER: Full or part ‑ time work More than one job Occupation Workplace location Usual distance to work Usual travel time to work Drive alone or carpool Work from home If commercial driver, amount of commercial travel FOR EACH VEHICLE: Make Model Age (year) DAILY TRAVEL DATA: Origin & destination address (geocoded to Latitudes and Longitudes) Time trip started and ended Distance Means of transportation Vehicle type If household vehicle, which one If transit, wait time If transit, access and egress modes Detailed purpose Number of others on trip Specific household members Number not household members Who drove Most recent trip, for non ‑ travelers (date)

Page 14 Kentucky Traffic Model Users Group: Travel Survey Workshop NHTS Data Collected (cont.): Geocoding Results Geocoding LevelNumber of LocationsPercentage Households Address Level1, % Closest Intersection201.7% Zip Code Centroid50.4% Non-Geocodable30.3% Work Locations Address Level % Closest Intersection867.6% Zip Code Centroid766.7% Non-Geocodable363.2% Trip Destinations Address Level7, % Closest Intersection9019.2% Zip Code Centroid6626.8% Non-Geocodable3513.6%

Page 15 Kentucky Traffic Model Users Group: Travel Survey Workshop NHTS Summary of Participation  50% of eligible households provided household-level information. Household response rate ~40%  Detailed travel information collected from ~53% of households that completed the household interview and agreed to provide travel information  ~40% of all attempted person-level interviews were completed  The overall, person-level response rate for the study ~18% –Scott County Telephone Issues –Person-level RR lower in Pulaski and Scott –HH level issues were refusals and no-contacts (Scott) –Person-level issues were no-contact cases

Page 16 Kentucky Traffic Model Users Group: Travel Survey Workshop NHTS Results: Summary of Participating Households

Page 17 Kentucky Traffic Model Users Group: Travel Survey Workshop NHTS Note on Survey Weights  The NHTS utilized a complex sampling scheme – i.e. this isn’t a simple random sample!  Survey weights were developed for each type of data (household, person, vehicle, trip-level) –Account for complex survey design –Differences in non-response –Post-stratification  Survey weights should always be used when calculating standard errors or measures of precision (e.g., confidence intervals)

Page 18 Kentucky Traffic Model Users Group: Travel Survey Workshop NHTS Results: Miles of Travel Vehicle Miles of Travel 3,435,945 or 1,254,120,088 Annualized Miles Per Vehicle 32.1 or 11,702 Annually Person Miles of Travel 5,329,575 or 1,945,294,783 Annualized Miles Per Person 41.7 or 15,220 Annually

Page 19 Kentucky Traffic Model Users Group: Travel Survey Workshop NHTS Results: Trips Trips per Household per Day 5.7 Vehicle Trips/HH 9.1 Person Trips/HH Total Number of Reported Trips Person TripsVehicle Trips 453,554285, ,547,299 Annually104,358,225 Annually Trips per Person per Day 2.2 Vehicle Trips/person 3.5 Person Trips/person

Page 20 Kentucky Traffic Model Users Group: Travel Survey Workshop NHTS Results: Percentage of Trips by Day of the Week

Page 21 Kentucky Traffic Model Users Group: Travel Survey Workshop NHTS Results: Percentage of Trips by Trip Purpose

Page 22 Kentucky Traffic Model Users Group: Travel Survey Workshop NHTS Results Many More Results…..