Understanding Activity Patterns and Trends David Levinson

Introduction Travel and Activity are Two Sides of the Same Coin Time in Travel is inseparable from Time at Activity Activities Considered (Home, Work, Shop, Other) Daily Activity Budget (24 hrs)

Space- Time Prism

2001 NHTS: Trips By Purpose

Montgomery County Trends

Patterns

Information Networks Fundamental question … how do we choose non-work destinations? First time (acquire information) Repeats (experience, habit) Choose between known and unknown destinations.

Where does Information Come From Formal: media networks: TV, Radio, Internet, Yellow Pages Informal: social networks

Changes in Retail

Economies of Scale in Supermarkets

Questions Is congestion rising? Are commutes getting longer? Are people spending more time commuting? Are people spending more time traveling? How do the declining trip times and increasing speeds reconcile with the general perception of worsening congestion?

More Questions What do travel and activity depend on? Is spatial determinism correct? Does income matter? Does location matter? Does demographics matter?

Rational Locator Hypothesis Despite falling speeds and increasing distances, average travel time can remain constant. Individuals will adjust their home and work locations in order to maintain commuting durations in the face of rising congestion. Dispersion and decentralization are conscious choices that enable rational locators to achieve their goals.

Rational Allocator Hypothesis Changes in Time Allocation (1968 to 1988) due to rising female labor force participation. Can be understood in context of Bounded Rationality “Allocators” - shape temporal activity patterns within household, spending time and money to produce household goods, maximizing utility. Technology, rising per capita income, and labor force participation create substition of in-house activities by out-of-home activities. E.g. eating out, day care.

Activity Duration Calculation

DC Time Use Data

Twin Cities Time Use Data

* Denotes Significance at 95% level Comparison of 1990 and 1995 NPTS

Change in Person Work Trip Volume (AM Peak Period) DESTINATION:CENTER CITYINNER SUBURBSOUTER SUBURBSTOTAL ORIGIN‘68‘88  ‘68‘88  ‘68‘88  ‘68‘88  CENTER CITY INNER SUBURBS OUTER SUBURBS TOTAL

Change in Average Work Trip Time (AM Peak Period) DESTINATIO N CENTER CITYINNER SUBURBSOUTER SUBURBSREGIONAL AVERAGE ORIGIN‘68‘88  ‘68‘88  ‘68‘88  ‘68‘88  CENTER CITY INNER SUBURBS OUTER SUBURBS

Drive Alone Trip Distribution

Trip Distances and Speeds Increased for Work Trips by All Modes (6.5 to 7.8 (> 20%) miles Euclidean (multiply by 1.4 or so to get Network Distances)) Distances increased slightly for nonwork trips (< 10% for home based, about 25% for other to other ) Speeds up in general (~20% for work trips).

Resolving the Paradox Suburban Arterial Urban Radial 1968 Speed55 MPH25 MPH 1988 Speed40 MPH20 MPH 1968 Traffic10%90% 1988 Traffic50%

Weighted Averages While Speed drops on both facilities, Average Speed rises from 28 MPH to 30 MPH. More generally, speed can drop on every facility from the day it opens as traffic increases, but if people increasingly use higher speed facilities, that use will outweigh the speed drop. This may be of little comfort to the commuter whose work trip becomes worse every year until he relocates.

Trip Chaining As available time shrinks, trip chaining is a practical substitute. Rather than –home to work to home to other to home. We see –home to work to other to home.

Trip Peaking: Work Trips

Trip Peaking: Nonwork Trips

Travel and Activity Patterns 1990 vs NPTS Time Spent at Home Decreased for Non Workers and Female Workers Time at Home in 1990 Substituted for Work in 1995, especially for Female Workers Time Spent at Other Declined for Workers but Increased for Non-Workers Overall Travel Times have either remained Stable or Increased, but not significant

Travel Duration Travel Duration = f( Activity Duration & Frequency) TDi = ß0 + ß1 * ADi + ß2 * AFi Transport Planning Models Only Consider Activity Frequency, not Duration ADi positive & significant in 6 of 9 activity categories, negative & significant for 1 of 9 (home) [ Staying Home is Substitute for Travel ]

Correlations: Activity Complements or Substitutes Non-Travel Activities are Substitutes Travel is Complementary to Like Activity & Travel to Home; Substitutes for Other Activities.

Conclusions Activity Duration a key factor explaining travel duration Activities are substitutes Travel is complement only to like activity & return trip Activity Duration is fairly constant between groups, with large individual variations which are not easily predicted

LifeCycle & Time at Home

LifeCycle & Time at Work

LifeCycle & Time at Shop

LifeCycle & Time at Other

LifeCycle & Time at Travel

Choice Model Logit model to predict share of time between 4 activities (incl. travel to act.) for individuals who undertook all four Greatest part of explanatory power is in Activity Specific Constant. 2nd most sig = activity frequency

Activity Duration Space (density, metro area, region) Money (income, work-status, gender) Life-Cycle (age, gender, household size, # adults, age of oldest child)

Work Outside HomeWork at HomeNonworkersAll Persons MFMFMFMFTotalHousehold HOME WORK SHOP OTHER TOTAL Mean Activity Frequencies

Work Outside HomeWork at HomeNonworkersAll Persons MFMFMFMFTotalHousehold HOME WORK SHOP OTHER TOTAL Mean Activity Durations

Home Time spent at Home dropped for workers and nonworkers, men and women. Why? Mobility, substitution of out-of-home activities.

Work Marked trend in increase time at work. Female labor force participation increases However, for workers, time at work decreased. Contrast with “Overworked American” argument.

Shop With rising income, people should shop more, right? However, time available for shopping drops as more women worked. So while both workers and non-workers shop more, the overall time spent shopping is steady (increased for men, decreased for women). Once again, Weighted Averages help explain our paradox.

Other Other: Pickup Drop Off, School, Unspecified other activies (doctor, bank, church, recreation, eating out, etc.) Men did more other than women in 1968, less in Overall, there is more time at other activities. Non-work is rising. Nonworkers (as expected) do more nonwork than workers.

Travel Time spent traveling has increased sharply. Commuting time has held steady. Thus non-commuting (nonwork) travel is the source of most rise in travel demand. There is no overall travel budget in DC. This is in contrast with other findings for other areas (e.g. Twin Cities, see Barnes and Davis)

References Levinson, David and Ajay Kumar (1994). "The Rational Locator: Why Travel Times Have Remained Stable." Journal of the American Planning Association, Summer : Levinson, David and Ajay Kumar (1995). "Activity, Travel, and the Allocation of Time." Journal of the American Planning Association. 61: activity.pdf + Levinson, David "Space, Money, Life-cycle, and the Allocation of Time." Transportation 26:2:

NPTS Data 1990/91 and 1995/96 Nationwide Personal Transportation Survey 1990 and 1995 Federal Highway Administration Highway Statistics Individuals whose total activities did not add to 1440 minutes (24 hrs), excluded This study looks only at adults, years of age Excluded travelers with a daily shopping time greater than 420 minutes 1990 Survey Households, individuals, Trips

MWCOG Data 1968 and 1987/88 Household Travel Surveys 1968: 20,000 Households Making 135,000 Trips 1987/88: 8,000 Households Making 55,000 Trips For Consistency, Analysis limited to 3 rings (though 1987 survey examined a somewhat larger area). Key Activities: Home, Work, Other Key Modes: Drive Alone, Carpool (2, 3+), Walk to Transit, (Park and Ride, Kiss and Ride in 1988),

Mean Travel Time by Mode and Purpose Work Trips Home-Based Nonwork Work-Based Nonwork Other-Based Other Drive Alone Drive Alone Carpool Carpool Carpool Carpool Walk to Transit Walk to Transit Park and Ride Kiss and Ride Walk All Modes All Modes

Myths 1.The long commute is commonplace 2.Jobs Housing Balance doesn’t matter 3.‘Sprawl’ makes congestion worse 4.Travel times are rising 5.Transit investment will lower travel times 6.Most travel is work trips

Commuting and Non- Commuting Rational Locator hypothesis suggests something like a loose commuting time budget. Clearly there is a total time budget (24 hours in a day). Is there an overall travel time budget?

1988 Distribution by Mode