using nhts to estimate activity patterns heather contrino, travel surveys team leader fhwa office of...

Using NHTS to Estimate Activity

Patterns

Heather Contrino, Travel Surveys Team LeaderFHWA Office of Highway Policy Information

Nancy McGuckin, Travel Behavior AnalystYuki Nakamoto, SAS Programmer Extraordinaire

Planning Applications Conference, 2007

Objectives

To explore the application of travel survey data for activity analysis and AB Model inputs: Fill data gaps for transportation planners, Provide guidance on key determinants of

travel, Support benchmarking and testing during

transition time from four-step to new generation, and

Assess trend behavior in use of time/activity

Data Steps…

1. Bridge the trip purpose codes and activity types using three categories: subsistence/mandatory, maintenance, and discretionary

2. Re-code the trip file into home-to-home tours3. Develop profiles of traveler types (developed

with CART) to look at time spent in each activity type, and time spent in travel for each activity type

4. Examine Trends in activity patterns using traveler profiles

Step 1: Bridge Trip Purposes into Activity Types

Percent of Trips within Mandatory/Subsistence Category

Step 1 – Bridging Trips and Activities

Source: 2001 NHTS

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0

School/rel.activity

Attendmeeting/bus.

Trip

Attendschool

Other w orkrelated

Return toWork

Go to w ork

2013

2114

1211

Sub

sist

ence

Percent of Trips

Step 1 – Bridging Trips and ActivitiesPercent of Trips within Maintenance Category

Source: 2001 NHTS

0 10 20 30 40 50

Day Care

P rof Services:attorney/accountant

P et care:walk the dog/vet

Attend meeting: P TA/localgov't

Buy gas

Medical/dental

Shopping/errands

Buy services:video/drycleaner/post office/car

Get/eat meal

Buy goods:Groceries/clothing/hardware

P ercent of Trips

0 5 10 15 20 25 30

Go to library:school related

Attend funeral/wedding

Visit public place

Go out to eat as social event

Rest/relax

Personal services:haircut

Social/Rec

Go to religious activity

other uncoded

Coffee/ice cream/snacks

Go out to to entertainment/sports event/bar

Family and personal

Go to gym/exercise/sports

Visit friends and rels

2362

5581

5263

5022

9083

5460

5153

Dis

cret

iona

ry

Percent of Trips


Percent of Trips within Discretionary Category

Source: 2001 NHTS

Percent of Trips by Activity Category

28.3

40.7

19.5

11.5

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

Mandatory Maintenance Discretionary ServePassenger

Pe

rce

nt

Result: Maintenance activities account for the largest share of trips


Source: 2001 NHTS

Step 2: Code the NHTS into home-to-home tours

Trip 2 Walk

Work

Home

Trip 3 Walk

Lunch at Restaurant

Trip 4 Walk Subway, car

Trip 6 Car

Trip 7 Car

Grocery store

Daycare center

Trip 1 Car, subway, walk

Gas Station

Trip 5 Car

93.2 percent of daily travel is in Home-to-Home tours

2.5 percent of daily travel tours start at home but don't return home at the end of the day

2.9 percent of daily travel tours start at a non-home location but return home

1.4 percent of daily travel tours neither start at home nor return home

Step 2 – Code Home-to Home Tours

Not all people begin and/or end the day at home

Some home-to-home tours are complex, including households with multiple workers and many activities


Disc Home

Main

19.0%

18.6% Home

17.3% Subs Home

60 percent

are simple

5.1% Serve Pass Home

Home

But most home-to-home tours are simple


Subs Home

Subs

17.3%

1.7% Home

0.7% Main Sub

1.0% Subs Disc

Main

Home

Home

.4% Disc Subs Home

.6% Serve Pass Subs Home

.4% Subs Serve Pass Home

2.8% ***** Subs ***** Home

Only 4.8% had one

other activity

stop and 2.8 % had more than

one

Note: People can have more than one activity at a location

Home

26 percent of tours include subsistence activities:


Step 3: Develop Traveler Profiles

Start with characteristics that determine travel from CART (Cluster Analysis Regression Tree), e.g.:

Worker status Vehicle Availability Presence of Children (we used ‘dependants’ who do not

drive) Sex

Then run the number of activities, time in activities, travel time, total out-of-home time, etc by these profile demographics

Then do it for 1995 and look to see if any trends emerge

Look for the groupings that define population segments for activity analysis:

Step 3 – Develop Traveler Profiles

Worker status showed greatest difference in time spent in activities out-of-home: Workers spend more time out-of-home and less time

in maintenance and discretionary activities Non-workers spend nearly as much time in daily

travel as do workers. Less work may not equal less travel

Presence of dependants/children effected both working and non-working women’s time in maintenance activities

Early Findings


Time Spent in Out-of-Home Activities - 2001

0

100

200

300

400

500

600

Men Women Men Women Men Women Men Women

No Dependants Dependants No Dependants Dependants

Worker Non-Worker

Enough Cars

Min

ute

s p

er

Da

y

Maintenance Discretionary Mandatory

Workers spend more time in out-of-home activities – slightly over 8 hours per day


Source: 2001 NHTS

Time Spent in Out-of-Home Activities - 2001

0

100

200

300

400

500

600

Men Women Men Women Men Women Men * Women


Worker Non-Worker

Not Enough Cars

Min

utes

per

Day


This is true even if there are fewer vehicles than drivers…

Source: 2001 NHTS


Time Spent in Travel 2001

0

20

40

60

80

100

120



Worker Non-Worker

Enough Cars

Min

ute

s p

er

Da

y


Source: 2001 NHTS

Non-workers spend nearly as much time in daily travel as do workers…


Time Spent in Travel - 2001

0

20

40

60

80

100

120

Men Women Men Women Men Women Men * Women


Worker Non-Worker

Not Enough Cars

Min

ute

s p

er

Da

y


Source: 2001 NHTS

Even when there are fewer vehicles than drivers…


What are the Trends in Activity Patterns?

Altogether, people are spending more time at home; just under 30 minutes a day -- (is this Internet effects? Social changes? Big screen TVs? Not aging cohorts within adult men—I checked by age group)

Workers are reporting more time in mandatory activities and more minutes of travel every day for mandatory

Workers are spending less time in out-of-home discretionary activities, but slightly more time in travel for discretionary

All groups are spending much less time in out-of-home maintenance activities, but slightly more time in travel for maintenance

Summary of Early Findings

Step 4 – Examine Trends

Since 1995, both men and women report spending more time at home…

Trends in the Amount of Time Spent at Home

780

800

820

840

860

880

900

920

Workers Men Women

Min

ute

s p

er

Day

1995 2001


Time Spent in Mandatory/Subsistence Activities

0

50

100

150

200

250

300

350



Worker Non-Worker

Enough Cars

Min

utes

per

Day

1995 Mandatory 2001 Mandatory

Source: NHTS Data Series

And workers are reporting more time in mandatory/subsistence activities


Trends in Daily Minutes of Travel for Mandatory/Subsistence

0

5

10

15

20

25

30

35

40

45

50



Worker Non-Worker

Enough Cars

Min

ute

s p

er

Da

y

1995 Mandatory 2001 Mandatory


While just slightly more time in travel for mandatory activities


Time in Maintenance Activities

0

50

100

150

200

250



Worker Non-Worker

Enough Cars

Min

utes

per

Day

1995 Maintenance 2001 Maintenance

All groups are spending less time in out-of-home maintenance activities as compared to 1995



Trends in Daily Minutes of Travel for Maintenance

0

10

20

30

40

50

60



Worker Non-Worker

Enough Cars

Min

utes

per

Day

1995 Maintenance 2001 Maintenance

And slightly more time in travel for out-of-home maintenance activities…



Time Spent in Discretionary Activities

0

20

40

60

80

100

120

140

160



Worker Non-Worker

Enough Cars

Min

utes

per

Day

1995 Discretionary 2001 Discretionary


All workers are spending less time in out-of-home discretionary activities


Trends in Daily Minutes of Travel for Discretionary

0

5

10

15

20

25

30

35

40

45



Worker Non-Worker

Enough Cars

Min

utes

per

day

1995 Discretionary 2001 Discretionary

But all groups are spending more time in travel for discretionary activities



Summary Overall, most tours are simple Workers and non-workers have similar daily amounts of

time in travel (is there a minimum threshold to ‘travel time budgets’?)

Non-workers travel more and spend more time in Maintenance and Discretionary activities

Less time constraint ≠ less travel

As baby-boomers retire will they travel more for maintenance and discretionary activities?

Trends show workers spending less time in maintenance if people are substituting/multi-tasking at work then let’s not

just focus on substitution ‘at-home’

Further Analysis Look at the complexity of tours/activity patterns related to

urban area size Are simple tours less likely in large metro areas?

Look at shared activities/shared rideStill haven’t untangles inter-household interaction/decision making aspectAuto constraint of less cars than drivers didn’t show much difference in behavior

Suggestion: try to separate shopping more precisely into maintenance or discretionary

Suggestion: better data on work-at-home and at-work multi-tasking

Other suggestions on data gaps?

Shared activity between household members

This schema does not include children’s activities, which is available in NHTS and also more likely to result in shared activity and travel

General Schema of NHTS Trip Data

Look at Shared Activities

Look at shared ride

Carpool Fam-pool All

1990 HBW 24.5% 75.5% 100%2001 HBW 17.0% 83.0% 100%2001 Work Tours 26.3% 73.7% 100%

All=All Multi-Occupant Vehicle Trips

Thank You!

Visit our website:http://nhts.ornl.gov

Contact:[email protected]@dot.gov

using nhts to estimate activity patterns heather contrino, travel surveys team leader fhwa office of...

Documents

home slide

home step

home tours

home time

code home

activities step

travel time

nonhome location