Thresholds and Impacts of Walkable Distance for Active School Transportation in Different Contexts

Transcription

1 Thresholds and Impacts of Walkable Distance for Active School Transportation in Different Contexts Xuemei Zhu, Chanam Lee, Zhipeng Lu, Chia-Yuan Yu College of Architecture, Texas A&M University

2 CONTENT I. Background II.Literature Review III.Study Design IV.Results V.Discussion

3 BACKGROUND Distance: One of the strongest correlates of walking to school (WTS) Questions about walkable distance remain What is the threshold? Does its impact vary by context? Significance: Inform school planning & future interventions thinksmartplan.com/wordpress/wpcontent/uploads/2010/08/parent-pick-up.jpg

4 How do we plan for walkable schools/neighborhoods? What is walkable? Schematic of a neighborhood unit for modest dwellings (Perry, 1929)

5 LITERATURE REVIEW Found 43 studies that examined impacts of distance 36 reported negative impacts 21 used continuous variables of distance (15 based on parental/child estimate, 6 based on objective measures) 15 used categorical variables of distance with thresholds of 0.25, 0.5, or 1 mile (mostly based one parental estimate)

6 LITERATURE REVIEW A few examined thresholds of walkable distance One asked parents about perceived thresholds A few used cumulative %s of WTS per covered distance o 1 km, 0.8 km & 0.5 km ranges used (too coarse) o 85% & 50% WTS used to decide the criterion distance A few studied age/gender-specific thresholds No studies on context-specific thresholds

7 STUDY DESIGN Cross-sectional study Data collection Parental survey in Austin (2007 & 2010, n=6233) (Collected: school travel modes; personal, social & physical environmental factors) Geocoding & shortest route analysis Data analysis Descriptive statistics: Cumulative %s of WTS Threshold of walkable distance Structural Equation Modeling predicting perceived close-enough distance & WTS

8 STUDY SETTING Downtown

9 STUDY SETTING Mean (Standard Deviation) of Physical Environmental Characteristics School type Population density (/acre) Living within ½ mile (%) Sidewalk completeness Street intersection density Inner city, lowincome (4 schools) Urban, lowincome (8 schools) Urban, midincome (4 schools) 9.3 (4.7) 11.2 (3.2) 6.6 (1.5) 2.5 (1.6) 39 (23) 28 (15) 23 (5) 14 (6) 36 (9) 38 (19) 28 (12) 8 (1) Suburban; highincome (6 schools) 0.32 (0.16) 0.18 (0.05) 0.20 (0.06) 0.12 (0.07) Land use mix 0.57 (0.12) 0.54 (0.15) 0.48 (0.21) 0.18 (0.17) Crash rate 9.0 (2.5) 6.9 (3.5) 5.1 (3.4) 1.9 (1.3) Crime rate 100 (35) 102 (52) 40 (15) 10 (8) Sample map

10 STUDY POPULATION Downtown Mean (Standard Deviation) of Population Characteristics School type Inner city, lowincome (4 schools) Urban, lowincome (8 schools) Urban, midincome (4 schools) Hispanic (%) a 90 (6) 82 (4) 58 (15) 15 (6) Free or reduced- price 92 (1) 94 (3) 65 (12) 7 (6) lunch (%) a Medium household income c Suburban; highincome (6 schools) 24,303 (1,878) 36,257 (3,737) 45,531 (8,506) 87,123 (21,030) a For total student enrolment at school; b For the survey sample; c Based on the Census data.

11 RESULTS GIS ANALYSIS: Shortest Home-to-School Route

12 DESCRIPTIVE STATISTICS Mean (Standard Deviation) or Frequency of Physical Environmental Characteristics School type Total Sample size by school Hispanic students among respondents Highest parental education (range: 1 lowest-6 highest) Students walking to/from school Parents perceiving closeenough distance Students with school bus service Home-to-school distance (Mile) Child crossing freeway en route to school Inner city, lowincome (4 schools) Urban, lowincome (8 schools) Urban, midincome (4 schools) Suburban; high-income (6 schools) 202 (91) 383 (133) 208 (24) 271 (101) 90% yes 85% yes 54% yes 13% yes 2.8 (1.1) 2.7 (1.1) 4.0 (1.4) 5.4 (0.8) 29% Yes 44% Yes 28% Yes 22% Yes 40% Yes 55% Yes 47% Yes 56% Yes 56% Yes 29% Yes 25% Yes 28% Yes 1.45 (1.60) 0.92 (1.35) 1.67 (2.35) 1.87 (2.15) 19% Yes 15% Yes 15% Yes 18% Yes

13 Walkable Distance What is the threshold? Does distance & WTS have a linear relationship? Does it vary by contexts?

14 Home-to-school Distance for Different Groups Descriptive statistics for home-to-school distance Perception of Distance close enough Yes No Total Mean=0.550 Mean=1.303 Mean=0.691 Yes S.D.=0.738 S.D.=2.061 S.D.=1.143 Walking to/from school N=1693 (27.16%) Mean=0.864 N=390 (6.26%) Mean=2.15 N=2083 (33.42%) Mean=1.680 No S.D.=0.989 S.D.=2.310 S.D.=2.023 N=1509 (24.21%) N=2641(42.37%) N=4150 (66.58%) Mean=0.698 Mean=2.044 Mean=1.349 Total S.D.=0.880 S.D.=2.293 S.D.=1.838 N=3202 (51.37%) N=3031 (48.63%) N=6233 (100%)

15 WTS within Different Distance Ranges (Total Sample) Walking to/from school (%) 100% 75% 50% 25% 0% 0.52 miles 0.85 miles Home-to-school distance (Miles) Home-to-school distance (Miles)

16 WTS in Different Distance Ranges (Sub-samples) 100% 75% Inner-city low-income Yes (%) Urban Low-income Yes (%) Urban Mmid-income Yes (%) Suburban high-income Yes (%) 50% 25% 0% 0.41 miles 0.52 miles

17 Cumulative % of WTS & Perceived Close-Enough Distance, by Home-to-School Distance 0.4 miles 0.93 miles

18 Cumulative % of Walking to/from School by Distance in Different Contexts

19 Cumulative % of Perceiving Close-enough Distance in Different Contexts 0.75 miles 1.05 miles 1.25 miles 1.52 miles

20 Predict Perceived Walkable Distance Completed analysis: used the 2007 survey sample Final analysis: will combine 2007 & 2010 samples & run separate models for 4 types of contexts

21 A: B: C: AIC: ; BIC: ; Adjusted BIC: R-square:.834 OR=.015 Obj. HTS Distance Perceived Safety OR= *** OR=1.609 Distance X Safety AIC: ; BIC: ; Adjusted BIC: R-square:.834 Obj. HTS Distance OR=.015 OR=.509 Perceived Safety Model Comparison AIC: ; BIC: ; Adjust Per. Close Distance.592 R-square:.834 AIC: ; BIC: ; Adjusted BIC: AIC: ; BIC: ; Adjust R-square:.834 OR=.015 R-square:.834 Obj. HTS Distance *** OR=.015 OR=.509 OR=.015 Obj. HTS Distance *** -.187* Perceived Obj. HTS Distance Safety *** OR= * OR=1.609 OR= Perceived Safety AIC: ; Per. Close BIC: Distance ; -.187* Adjust Per. Close Distance Distance Perceived X Safety Safety OR= R-square:.834 OR= AIC: ; BIC: ; Adjusted BIC: Distance X Safety AIC: ; BIC: OR= ; Adjust R-square:.834 Distance X Safety R-square: Obj. HTS.834 OR=.015 Distance *** OR=.015 OR=.509 Obj. HTS Distance *** Obj. Perceived HTS Distance Safety *** -.187* OR=.509 OR=.509 OR= *.599 Perceived Safety AIC: Perceived Distance ; X Safety BIC: ; -.187* Adjust OR= Per. Close Distance R-square:.799 OR=1.617 OR= AIC: Distance ; X Safety BIC: ; Adjusted BIC: AIC: Distance Sidewalk ; X Compl. Safety BIC: OR= ; Adjust R-square: Per..799 Close OR=.907 Distance R-square: Obj. HTS.799 Distance OR=.027 OR=.907 Sidewalk Compl ** Sidewalk Compl. OR=.531 OR=.027 Obj. HTS Distance ** Perceived Obj. HTS Distance Safety OR= ** OR=1.499 OR=.531 Perceived Safety (Note: Standardized results) Distance Perceived X Safety OR= * *** -.187* OR= Distance X Safety OR=.907 AIC: Sidewalk ; Compl. BIC: ; Adjusted BIC: R-square:.799 OR=.027 Obj. HTS Distance OR=.531 Perceived Safety OR=1.499 Distance X Safety ** OR= * Sidewalk Compl..067*** OR=1.345 Car Ownership -.107*** OR=.401 Bus Availability

22 SEM Predicting Perceived Close Distance: Model C AIC: ; BIC: ; Adjusted BIC: R-square:.799 Obj. HTS Distance Perceived Safety Distance X Safety Sidewalk Compl. Car Ownership OR=.027 OR=.531 OR= ** OR= * OR= *** -.107*** Per. Close Distance Bus Availability OR=.401

23 Predict Walking to/from School 1. Test the mediator role of perceived walkable distance in influencing WTS 2. Predict WTS using personal, social & physical environmental variables

24 A: B: C: mediator role of perceived walkable distance : AIC: ; BIC: ; Adjusted BIC: OR=.324 Model Comparison Bus Availability *** OR= *** AIC: ; BIC: Car Ownership Walk to School AIC: ; BIC: ; OR=.324 Adjusted BIC AIC: ; BIC: ; OR=.324 Adjusted Bus Availability BIC: Obj. HTS Distance OR=.324 Bus Availability OR= *** *** OR=.220 Bus Availability OR=.735 Car Ownership *** -.308*** AIC: ; BIC: ; Adjusted BIC: OR=.735 Car Ownership -.308*** OR=.318 Car Ownership Obj. HTS Distance Bus Availability Obj. HTS Distance *** AIC: ; OR=.220 OR=.655 Obj. HTS Distance BIC: *** -.424*** Car Ownership Walk AIC: to School ; OR=.220 BIC: ; OR=.318 Adjusted BIC 1.858*** *** OR=.068 OR=6.408 AIC: ; OR=.220 BIC: ; OR=.318 Adjusted Bus Availability BIC: *** Obj. HTS Distance Per. Close Dist. OR=.318 Bus Availability OR= *** (X4) AIC: ; BIC: ; Adjusted BIC: Bus Availability OR=.655 Car Ownership *** -.424*** OR=.370 OR=.655 Car Ownership OR= *** Bus Availability -.995*** Car Ownership OR=.068 Obj. HTS Distance OR *** 1.858*** OR=.671 OR=.068 Obj. HTS Distance AIC: ; OR=6.408 BIC: Per. Close *** *** Car Ownership Obj. HTS Distance Walk AIC: to School ; BIC: Per ; Close Dist. OR=.370 Adjusted (X4) BI 1.234*** OR=.068 OR=3.436 AIC: ; BIC: ; (X4) ** OR=.370 Adjusted Bus Availability BIC: Obj. HTS Distance Per. Close Dist. OR=.370 Bus Availability OR=.671 (X4) -.995*** OR= *** Bus Availability OR=.671 Car Ownership -.995*** -.399*** OR=.671 Car Ownership OR= *** Car Ownership OR=.068 Obj. HTS Distance O ** 1.234***

25 SEM Predicting WTS: Model C AIC: ; BIC: ; Adjusted BIC: OR=.370 Bus Availability Car Ownership OR=.671 OR=.068 Obj. HTS Distance OR= ** -.995*** -.399*** 1.234*** OR=3.436 Per. Close Dist. (X4) *** Walk to School (Unstandardized results.)

26 SEM Predicting WTS: Measurement models tested first Personal factors.566***.617***.494***.504***.664*** R 2 =.434*** Too much planning R 2 =.383*** Easier to drive R 2 =.506*** Too much to R 2 =.496*** Too hot R 2 =.336*** No time to Walk.659***.619***.711***.704***.580*** Hispanic Highest education # of fam. members Car ownership OR=1.351 OR=.843 Walking Barriers OR=1.158 OR=.720 OR=.389*** ***.082*** -.105*** -.349*** Model fit tested N=2, ***.479***.393***.426***.456*** R 2 =.555*** Kid think WTS cool R 2 =.521*** Kid walks often R 2 =.607*** Walk good R 2 =.574*** Peo in neigh walks R 2 =.544*** Enjoy WTS w/ Kid.745***.722***.779***.757***.737***.777***.529*** OR=2.184 Positive Attitudes.517*** -.177*** Social factors.396***.260***.129***.190*** R 2 =.604*** Family likes WTS R 2 =..740*** Other Kids WTS R 2 =..871*** Oth. K walk in daily R 2 =.810*** Oth parents walk.860***.933***.900***.780*** OR= *** Peer Influences OR= *** Walk to School Objective physical environment Bus availability -.515*** OR=.375 HTS distance.002 OR=1.026 Sidewalk complet. Crash rate Crime rate OR=1.007 OR=.999 OR=.651 % high speed road OR= * Presence of FWY

27 Personal factors OR=1.351 Hispanic OR=.843 R 2 =.434*** Highest education *** Too much planning R 2.659*** =.434*** OR=1.158 R R 2 =.383*** 2 =.434***.566*** Too much planning.617***.566*** # of Easier Too fam. much members to drive planning -.126***.619***.659***.659*** R 2 =.383*** OR=.720 R R 2 =.434*** =.506*** 2 =.383***.617*** Easier to drive.619***.494***.617*** Car Too ownership Easier much to to drive.082***.711***.619***.566*** Too much planning R 2 =.506*** carry OR=.389*** R =.496*** 2.659*** =.506*** R 2 =.383***.494*** Too much to.711***.617***.504***.494*** Too Too hot much to.711*** Easier Walking to drive R ***.704***.619*** carry =.496*** Barriers R R 2 =.336*** =.506*** 2 =.496***.504*** Too hot.704***.664***.580***.494***.504*** No Too Too time much hot to to Walk.711***.704*** R 2 =.336*** carry R.664***.580*** 2 2 =.496*** 2 =.336*** =.555*** No time to Walk.664***.580***.504***.445*** Kid Too No think hot time to Walk WTS cool.704*** -.349***.745*** R 2 =.555*** (X45).529*** R 2 =.521*** =.336*** 2 =.555***.445*** Kid think WTS cool.664***.479***.445***.745*** walks often.722***.580*** No Kid time think to WTS Walk cool.517***.745*** R 2 =.521*** (X46) (X45) R R 2 =.555*** =.607*** 2 =.521***.779***.479*** Kid walks often.722***.393***.479*** Walk Kid walks good OR=2.184 R 2 =.434*** often.722***.445*** Kid think WTS cool R 2 =.607***.779***.566*** interact. Too (X46) much (X47) R =.574*** 2 planning.757***.745*** (X45) R.393*** Positive 2 =.521*** =.607***.779***.659*** Walk good.479***.426***.393*** Peo Kid Walk in walks neigh good Roften 2 =.383*** walks -.177***.722*** Attitudes R 2.757***.737*** =.574***.617*** interact. Easier to R (X47) =.544*** 2.757*** (X46) R 2 =.607*** drive =.574***.619***.779***.426*** Peo in neigh walks.456***.393***.426*** Enjoy Walk Peo in good WTS neigh R 2 w/ =.506*** walks Kid.777***.737***.737*** R 2 =.544***.494*** interact. Too much to.711*** R (X47) R 2 =.604*** 2 =.544***.757*** =.574***.456*** Enjoy WTS w/ Kid.777***.396***.426***.456*** Peo Family Enjoy in neigh likes WTS R 2 =.496*** walks WTS w/ Kid.777*** R 2 =.604***.504*** (X51) Too hot R 2.737*** R =.604***.704***.396***.780*** R 2 =.544*** 2 =..740*** Family likes WTS.456***.396*** Enjoy Family WTS likes Other Kids R 2 WTS =.336*** w/ WTS Kid.777***.260***.860***.664***.580*** R 2 No (X51) time to Walk =..740*** R 2 OR=.959 =.604*** R 2 =..871*** 2 =..740***.396*** ***.260*** Other Kids WTS.860***.129***.260*** Oth. Family Other K walk likes Kids R 2 in =.555*** WTS daily.860*** R 2 =..871***.445*** (X51) Kid Peer think WTS R =.810*** 2 =..871*** cool.900***.933*** R 2 =..740***.933***.745*** Hispanic OR=.843 OR=1.351 Highest Hispanic education OR=1.351 OR=1.158 OR=.843 # Highest of fam. members education -.126***.050 Hispanic OR=.720 OR=1.158 OR=.843 Car # of ownership fam. members.082*** -.126** Highest education.050 OR=1.158 OR=.720 OR=.389*** Car ownership.082*** # of fam. members -.126*** -.105*** OR=.720 OR=.389*** Car ownership.082*** -.105*** OR=.389***.529***.529*** Hispanic OR=2.184 OR= ***-.34 Highest education *** Positive OR=2.184 OR= ***.517*** Attitudes # of fam. members -.126** OR=2.184 OR= *** Attitudes Car ownership.082***.780*** Positive Attitudes Walking Barriers Walk Peer to School Influences Peer.529*** OR=1.351 Walking Barriers Walking Barriers Walking Barriers Positive *** OR= *** OR=.389*** -.177*** -.105***.780*** OR= ***.780*** -.3 OR= *** OR= ***.517*** -.3

28 Social factors Objective physical environment.393***.426***.456***.396***.260***.129***.190*** Walk good R 2 =.574*** Peo in neigh walks R 2 =.544*** Enjoy WTS w/ Kid R 2 =.604*** Family likes WTS R 2 =..740*** Other Kids WTS R 2 =..871*** Oth. K walk in daily R 2 =.810*** Oth parents walk.757***.737***.777*** Attitudes -.177*** OR=1.351 Hispanic.780*** OR=.843 Highest Walk education.050 to School OR=.959 R 2 =.434*** *** OR= *** OR= *** Too much planning # of fam. members -.126*** Peer.659*** Hispanic.933*** R Influences 2 =.383*** OR= ***.900*** Easier to drive.619*** Car ownership OR= *** OR= *** Highest education.050 R 2 =.506*** Too much OR=.287 R 2 =.434*** Hispanic OR=.389***.494*** to.711*** OR= *** Walking Bus Too availability much planning # of fam. members OR=.843 R *** -.126*** =.496***.659*** *** Highest Barriers education.050 =.383*** OR= ***.617*** Too hot OR=.375 R 2 =.434*** Easier to drive.704***.619*** Car ownership OR= ***.566*** HTS Too distance much R 2 =.336***.002 R 2 planning # of fam. members -.126*** =.506***.664***.580***.659*** OR=.389*** No time to OR=1.026 Walk.494*** Too much R 2 =.383*** to.711*** OR= ***.617*** Sidewalk carry Easier complet. R 2 to drive Walking =.555*** R 2.619*** Car ownership -.105***.082*** =.496*** ***.445*** Kid think WTS OR=1.007 R 2 cool =.506*** Barriers.504*** Too hot OR=.389***.745***.704***.517***.494*** Crash Too rate much R 2 to.711*** =.521*** carry 2 =.336*** Walking.479*** Kid walks often OR= ***.664*** R *** =.496***.580*** No time to Walk Barriers OR=2.184 OR= *** Crime Too rate R hot 2 =.607***.779***.704*** Hispanic.393*** 2 =.555*** Positive Walk good OR=.651 R 2 =.336***.529***.445*** OR= ***.664*** Kid think WTS cool Attitudes % high speed R 2.757***.580*** No time.517*** (X45) =.574*** road to Walk.745*** Highest education *.426*** =.521*** Peo in neigh OR=.394 Rwalks 2.479*** Kid walks 2 =.434*** OR=1.158 =.555*** often.737***.722***.529*** OR= ***.445*** Presence Too Kid (X46) think much Rof 2 =.544*** FWY WTS planning # of fam. members -.126*** 2 cool =.607***.659***.456*** Enjoy WTS w/ Kid.777***.779***.745***.517*** (X45).393*** Positive Walk good R 2 =.521*** =.383*** OR= *** -.177***.479*** Easier interact. Kid Rwalks 2 =.604*** to drive (X47) Attitudes 2 often.722***.619*** Car ownership.082***.757*** OR=2.184 =.574***.396***.780*** Family (X46) likes WTS.426*** R 2 =.607*** =.506*** Peo in neigh walks.779*** OR=.389***.494***.393*** Too.737*** Positive Walk much good to.711*** R 2 =..740*** *** carry =.544*** Walking interact. (X47) OR=.959 Attitudes ***.260***.456*** R ***.757*** =.574*** =.496*** Other Enjoy Kids WTS w/ Kid.860***.777*** Barriers.504***.426*** Peo Too in hot neigh R 2 =..871*** 2 walks.704*** =.604*** Peer.933***.737*** R 2 =.544*** =.336***.780***

29 DISCUSSIONS 0.5-mile threshold for walkable distance (Consistent with some previous studies.) Perception of walkable distance is influenced by nondistance related factors & acts as a significant mediator in influencing WTS. (Implications for interventions.) Distance vs. walking to school is not necessarily a linear relationship, as shown in sub-group analysis, & the relationship varies by context. Distance & freeway are 2 significant physical environmental factors. (Future school/neighborhood planning should respond to this.)