Active Travel The Role of Self-Selection in Explaining the Effect of Built Environment on Active Travel

Transcription

1 Active Livig Research Buildig Evidece to Prevet Childhood Obesity ad Support Active Commuities RESE ARCH brief Fall 2009 activelivigresearch.org Active Travel The Role of Self-Selectio i Explaiig the Effect of Built Eviromet o Active Travel I their search for effective ways to ecourage physical activity, public health officials have tured their attetio to the built eviromet, focusig i particular o how eighborhood desig ca support walkig ad bikig. 1, 2 Numerous studies have documeted a coectio betwee eighborhood desig ad active travel (i.e., walkig ad bicyclig for trasportatio rather tha for recreatio) amog both childre ad adults. 3 For example, residets walk more for trasportatio i traditioally desiged eighborhoods those with safe sidewalks ad itersectios, ad a street etwork that provides direct access to earby shops ad other destiatios tha they do i typical U.S. suburba eighborhoods, where homes are separated from destiatios by major roads that hider walkig or bikig. While there clearly is a lik betwee eighborhood desig ad active travel, there are still questios about the ature of the cause-ad-effect relatioship that exists betwee them. Do places desiged for walkig ecourage people to walk more, or do people who like to walk prefer to live i places that are desiged for walkig? The latter, what researchers call self-selectio, is a importat cosideratio whe determiig how best to icrease opportuities for physical activity. 4 If differeces i active travel exist because residets who already are active self-select ito eighborhoods that support such travel, the improvemets to the walkig eviromet may ot ecourage residets to walk more. But ifrastructure improvemets could still lead to icreases i active travel by makig it possible for more people who prefer walkig or bikig to live i eighborhoods that support such activities. Researchers have employed differet approaches to determie whether ad to what degree self-selectio occurs, 5 though may studies focus o travel by all modes rather tha just o active travel. As demostrated by the research preseted i this brief, cosistet evidece is begiig to emerge that shows both self-selectio ad the built eviromet have a role i active travel. 6 A atioal program of the Robert Wood Johso Foudatio, with directio ad techical assistace provided by Sa Diego State Uiversity.

2 Active Livig Research activelivigresearch.org 2 Key Research Results Self-selectio is liked to higher levels of walkig i traditioally desiged eighborhoods People who preferred walkig for trasportatio teded to: 1) live i more traditioally desiged eighborhoods that are coducive to walkig; ad 2) walk more tha eighbors who have less preferece for walkig. 7 9 Accordig to a 2004 survey coducted i eight Norther Califoria eighborhoods, 64 percet of people livig i traditioally desiged eighborhoods reported that havig shoppig areas withi walkig distace of their home was a importat factor whe decidig where to live, while oly 53 percet of suburba-eighborhood residets reported the same. 10 As show i Figure 1, residets of both traditioal ad suburba eighborhoods who reported that it was very importat to have shoppig areas withi walkig distace walked to the store three to five times more tha those who said it was ot importat. 11 F i g u r e 1. Residets who preferred to have earby shoppig areas walked to the store more ofte regardless of eighborhood desig 12 Suburba Traditioal 7 6 Walks to store i last 30 days Not at all importat Shoppig areas withi walkig distace Very importat Neighborhood desig has a impact o walkig regardless of self-selectio People who lived i traditioally desiged eighborhoods geerally walked more for trasportatio tha did those i suburba eighborhoods, regardless of their walkig prefereces As Figure 1 shows, amog respodets who reported that havig shoppig areas withi walkig distace was very importat, those i traditioally desiged eighborhoods were much more likely to walk to the store tha were residets of suburba eighborhoods. While it is ot yet clear whether self-selectio or the built eviromet has a greater ifluece o active travel, 16 eight of the 10 studies i Table 1 that quatify these effects show that the built eviromet has a stroger effect o active travel tha does self-selectio. A atioal program of the Robert Wood Johso Foudatio, with directio ad techical assistace provided by Sa Diego State Uiversity.

3 Active Livig Research activelivigresearch.org Despite these isights, it is importat to ote that the existig body of research does ot fully explai why some people egage more i active travel tha others. For example, the survey of eight Norther Califoria eighborhoods foud that self-selectio, built eviromet factors ad socio-demographic characteristics together explaied oly about oe-third of the variatio i how ofte residets walked to the store. 17 This implies that the bulk of the variatio is explaied by factors such as prior experieces, which were ot icluded i the study. Ta b l e 1. Fidigs o built eviromet ad self-selectio effects by umber of studies 18 Effects Foud* Number of Studies Built eviromet effect but o self-selectio effect 1 Built eviromet effect ad self-selectio effect 15 (but o coclusio about which effect is greater) Built eviromet effect with self-selectio accouted for but ot measured 12 Built eviromet effect greater tha self-selectio effect 8 Built eviromet effect smaller tha self-selectio effect 2 Self-selectio effect but o built eviromet effect 0 *Icludig studies of travel by all modes ad studies of active travel. The demad for traditioally desiged eighborhoods appears to exceed the supply Both supply of 19 ad demad for 20, 21 traditioally desiged eighborhoods seem to be growig. Natioal surveys showed that iterest i livig i a traditioally desiged commuity grew from 44 percet i 2003 to 50 percet i 2005, ad that iterest icreased amog all respodets except for those who lived i rural areas. 22 Studies have show that more people wat to live i traditioally desiged eighborhoods tha are able to For example, a survey of more tha 1,400 residets of the Atlata regio foud that respodets who were more iterested i compact, mixed-use, walkig-orieted eighborhoods had a greater desire for a chage from their curret eighborhood tha did those who did ot idicate such iterest. 26 The size of the gap betwee supply ad demad is ucertai. While may people desire to live i traditioally desiged eighborhoods, they ofte also value cotradictory qualities. Usig data from a 1994 survey of 611 residets i Portlad, Orego, researchers foud that residets who preferred smaller lot sizes ad shorter walkig distaces to stores also preferred sigle-family homes ad off-street parkig. 27 A atioal program of the Robert Wood Johso Foudatio, with directio ad techical assistace provided by Sa Diego State Uiversity.

4 Active Livig Research activelivigresearch.org Icreases i active travel do ot ecessarily lead to icreases i total physical activity Accordig to a survey of 393 households i the Chapel Hill area of North Carolia, residets of traditioally desiged ew urbaist eighborhoods walked for trasportatio three to four times as ofte as residets of covetioal suburba eighborhoods, but the average levels of overall physical activity were idetical for the two groups. 28 Coclusio The results preseted i this brief show that creatig more traditioally desiged commuities may lead to at least a moderate icrease i active travel. At the same time, importat questios remai about the relative impact that idividuals attitudes, prefereces ad eviromets have o their choices about active travel. Several importat implicatios about strategies for icreasig active travel emerge from this research: Igorig the self-selectio factor is likely to lead to overly optimistic forecasts of the potetial effect of built eviromet strategies o active travel. Icreasig the supply of walkig-orieted commuities is likely to icrease active travel if it eables walkig-orieted residets to move from drivig-orieted to walkig-orieted eighborhoods i other words, if it allows them to self-select. Improvemets to the built eviromet that facilitate walkig have the potetial to icrease active travel for all residets, whether the eighborhood or its residets are walkig-orieted or ot. The potetial to icrease active travel through chages to the built eviromet likely is limited. Built eviromet strategies are importat, but they are ot likely to brig about substatial icreases i active travel o their ow. Several types of studies would help aswer the remaiig questios about self-selectio, 29, 30 although all are challegig ad few have bee coducted to date. Survey residets about their active travel before ad after a improvemet to the 31, 32 walkig or bicyclig eviromet i their existig eighborhood. Survey residets about their active travel before ad after they move from a drivigorieted eighborhood to a walkig-orieted eighborhood (or vice versa). 33, 34 Because these residets may be self-selectig ito the walkig-orieted eighborhood, the surveys also must iclude questios o attitudes ad prefereces. Track residets i log-term pael studies to show how their attitudes ad prefereces about active travel chage over time, whether i respose to the built eviromet or other factors. Examie how factors such as age, icome, umber of childre ad other factors affect people s ability to choose a walkig-orieted eighborhood. A atioal program of the Robert Wood Johso Foudatio, with directio ad techical assistace provided by Sa Diego State Uiversity.

5 Active Livig Research activelivigresearch.org 1 Frumki H, Frak L ad Jackso R. Urba Sprawl ad Public Health: Desigig, Plaig, ad Buildig for Healthy Commuities. Washigto, DC: Islad Press, Heath G, Browso R, Kruger J, et al. The Effectiveess of Urba Desig ad Lad Use ad Trasport Policies ad Practices to Icrease Physical Activity: A Systematic Review. Joural of Physical Activity ad Health, 3(Supplemet 1): S55 S76, Jauary Trasportatio Research Board ad Istitute of Medicie. Does the Built Eviromet Ifluece Physical Activity? Examiig the Evidece. Washigto, DC: Natioal Academies Press; Levie J. Access to Choice. Access, 14: 16 19, Mokhtaria P ad Cao X. Examiig the Impacts of Residetial Self-Selectio o Travel Behavior: A Focus o Methodologies. Trasportatio Research Part B, 42(3): , March Cao X, Mokhtaria P ad Hady S. Examiig the Impacts of Residetial Self-Selectio o Travel Behavior: A Focus o Empirical Fidigs. Trasport Reviews, 29(3): , May Hady S ad Clifto K. Local Shoppig as a Strategy for Reducig Automobile Travel. Trasportatio, 28 (4): , November Khattak A ad Rodriguez D. Travel Behavior i Neo-Traditioal Neighborhood Developmets: A Case Study i USA. Trasportatio Research Part A, 39(6): , July Hady S, Cao X ad Mokhtaria P. Self-Selectio i the Relatioship Betwee the Built Eviromet ad Walkig: Empirical Evidece from 10 Ibid. 11 Ibid. 12 Ibid. Norther Califoria. Joural of the America Plaig Associatio, 72(1): 55 74, March Khattak A ad Rodriguez D, Cao X, Hady S ad Mokhtaria P. The Iflueces of the Built Eviromet ad Residetial Self-Selectio o Pedestria Behavior: Evidece from Austi, TX. Trasportatio, 33(1): 1 20, Jauary Frak L, Saeles B, Powell K, et al. Steppig Towards Causatio: Do Built Eviromets or Neighborhood ad Travel Prefereces Explai Physical Activity, Drivig, ad Obesity? Social Sciece & Medicie, 65(9): , November Cao X, Mokhtaria P ad Hady S, Hady S, Cao X ad Mokhtaria P, Cao X, Mokhtaria P ad Hady S, Steuteville R. New Urba Neighborhoods Make Big Gais. New Urba News, 9(1): 1 6, Myers D ad Geari E. Curret Prefereces ad Future Demad for Deser Residetial Eviromets. Housig Policy Debate, 12(4): , Hady S, Sallis J, Weber D, et al. Is Support for Traditioally Desiged Commuities Growig? Joural of the America Plaig Associatio, 74(2): 22 Ibid , March Myers D ad Geari E, Levie J ad Frak L. Trasportatio ad Lad-Use Prefereces ad Residets Neighborhood Choices: The Sufficiecy of Compact Developmet i the Atlata Regio. Trasportatio, 34 (2): , March Levie J, Iam A ad Torg G. A Choice-Based Ratioale for Lad Use ad Trasportatio Alteratives: Evidece from Bosto ad Atlata. Joural of Plaig Educatig ad Research, 24: , March Levie J ad Frak L, Walker J ad Li J. Latet Lifestyle Prefereces ad Household Locatio Decisios. Joural of Geographical Systems, 9(1): , April Rodriguez D, Khattak A ad Eveso K. Ca New Urbaism Ecourage Physical Activity? Comparig a New Urbaist Neighborhood With Covetioal Suburbs. Joural of the America Plaig Associatio, 72(1): 43 56, March Mokhtaria P ad Cao X, Cao X, Mokhtaria P ad Hady S, A atioal program of the Robert Wood Johso Foudatio, with directio ad techical assistace provided by Sa Diego State Uiversity.

6 Active Livig Research activelivigresearch.org 31 Wells N ad Yag Y. Neighborhood Desig ad Walkig A Quasi-Experimetal Logitudial Study. America Joural of Prevetive Medicie, 34(4): , April Boaret M, Aderso C, Day K, et al. Evaluatio of the Califoria Safe Routes to School Legislatio: Urba Form Chages ad Childre s Active Trasportatio to School. America Joural of Prevetive Medicie, 28: , February Steuteville R, Krizek K. Residetial Relocatio ad Chages i Urba Travel: Does Neighborhood-Scale Urba Form Matter? Joural of the America Plaig Associatio, 69(3): , September Active Livig Research, a atioal program of the Robert Wood Johso Foudatio, stimulates ad supports research to idetify evirometal factors ad policies that ifluece physical activity for childre ad families to iform effective childhood obesity prevetio strategies, particularly i low-icome ad racial/ethic commuities at highest risk. Active Livig Research wats solid research to be part of the public debate about active livig. This report was prepared by Susa Hady, Ph.D., Uiversity of Califoria at Davis, Xiyu (Jaso) Cao, Ph.D., Uiversity of Miesota, ad Patricia Mokhtaria, Ph.D., Uiversity of Califoria at Davis, with support from the Active Livig Research staff. Peer review was provided by Marlo Boaret, Ph.D., Uiversity of Califoria at Irvie; Christie Hoeher, Ph.D., Sait Louis Uiversity; ad Kevi Krizek, Ph.D., Uiversity of Colorado, Dever. Visit for a Web-based versio ad other updates. Active Livig Research Sa Diego State Uiversity 3900 Fifth Aveue, Suite 310 Sa Diego, CA A atioal program of the Robert Wood Johso Foudatio, with directio ad techical assistace provided by Sa Diego State Uiversity.