National Academies Press: OpenBook

Livable Transit Corridors: Methods, Metrics, and Strategies (2016)

Chapter: Appendix G - Statistical Analysis of Metrics and Typology Categories

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Page 117
Suggested Citation:"Appendix G - Statistical Analysis of Metrics and Typology Categories." National Academies of Sciences, Engineering, and Medicine. 2016. Livable Transit Corridors: Methods, Metrics, and Strategies. Washington, DC: The National Academies Press. doi: 10.17226/23630.
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Page 117
Page 118
Suggested Citation:"Appendix G - Statistical Analysis of Metrics and Typology Categories." National Academies of Sciences, Engineering, and Medicine. 2016. Livable Transit Corridors: Methods, Metrics, and Strategies. Washington, DC: The National Academies Press. doi: 10.17226/23630.
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Page 118
Page 119
Suggested Citation:"Appendix G - Statistical Analysis of Metrics and Typology Categories." National Academies of Sciences, Engineering, and Medicine. 2016. Livable Transit Corridors: Methods, Metrics, and Strategies. Washington, DC: The National Academies Press. doi: 10.17226/23630.
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Page 119

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117 Table G-1 provides factor analysis results for 10 of the 12 metrics used in this Handbook. The two factor variables produced in this process were then used (along with the remaining 2 of 12 total metrics) as independent variables in an ordinary least squares (OLS) linear regression model to predict a proxy quality-of-life indicator variable: the corridor non-auto internal trip capture rate. Linear regression model results using the variables (factors) produced from the factor analysis model run plus the two remaining metrics—corridor pedestrian environment and corridor pedes- trian collisions per daily 100,000 pedestrians—are shown in Table G-2. Linear regression results suggest the collection of livability metrics (the independent variables) is a good predictor of transit corridor non-auto internal trip capture rates, and by inference, transit corridor quality of life. These findings helped the Handbook’s research team validate the metrics. Table G-3 provides analysis of variance (ANOVA) statistical analysis results suggesting that for the 250 outside-of-CBD corridors analyzed, the metrics used in this Handbook (including Housing Unaffordability and Income Diversity) have average values for each typology category that are significantly different from each other. These significant differences are consistent with the theoretical hypotheses posed prior to analysis and the values shown in Table 10 (see Step 3 for additional discussion of these results). These findings indicate that as a group, the 12 metrics used in this study are useful for distinguishing one typology category from another. Furthermore, since the linear regression model (see Table G-3) predicting corridor non-auto internal capture rates provided validation of the metrics, these ANOVA results also help validate the typology. A P P E N D I X G Statistical Analysis of Metrics and Typology Categories

118 Livable Transit Corridors: Methods, Metrics, and Strategies Rotated Component Matrixa Metric Factor 1 2 Transit employment accessibility 0.839 0.439 Corridor transit service coverage 0.795 0.486 Corridor housing unaffordability -0.137 -0.845 Corridor income diversity 0.680 Corridor jobs density 0.925 Corridor retail jobs density 0.897 -0.157 Corridor health care opportunities 0.705 0.522 Corridor density (population/acre) 0.754 0.463 Access to culture & arts 0.918 Ridership balance 0.332 0.101 Notes: N = 250 U.S. Transit corridors. Extraction method: Principal component analysis. Rotation method: Varimax with kaiser normalization. aRotation converged in 3 iterations. Total Variation Explained: 71.69%. Table G-1. Factor (loadings) analysis results summary table for outside-of-CBD corridors. Variable (Factor or Metric) Coefficient Significance Factor 1: Transportation/Land Use/ Livable Opportunities Integration 0.043 *** Factor 2: Housing Affordability & Income Diversity 0.164 *** Pedestrian environment (intersection density) 0.355 *** Pedestrian collisions per 100,000 pedestrians -0.256 *** Constant 0.093 ** Model Fit N1 31 R Square 0.914 Notes: 1Non-auto Internal Capture Rates developed for 31 transit corridors from California, Texas, and Florida National Household Transportation Survey Supplementary datasets. ** = p < 0.05 *** = p < 0.01 Table G-2. OLS linear regression results predicting outside-of-CBD corridor non-auto internal capture rates.

Statistical Analysis of Metrics and Typology Categories 119 Variable (Metric) Sum of Squares Degrees of Freedom Mean Square F- Statistic P-Value Transit Jobs Accessibility Between Groups 4.121E+10 2 2.061E+10 193.215 0.000 Within Groups 2.655E+10 249 106644971 Total 6.777E+10 251 Transit service coverage (aggregate frequency of transit service per square mile) Between Groups 1182198429 2 591099214 128.986 0.000 Within Groups 1136495917 248 4582645 Total 2318694345 250 Housing unaffordability (percent of income spent for housing) Between Groups 234.932 2 117.466 5.219 0.006 Within Groups 5648.862 251 22.505 Total 5883.794 253 Income diversity (variance from regional median household income) Between Groups .060 2 .030 6.161 0.002 Within Groups 1.218 251 .005 Total 1.278 253 Jobs density (employees/acre) Between Groups 15694.037 2 7847.019 165.450 0.000 Within Groups 11904.508 251 47.428 Total 27598.545 253 Retail jobs density (retail employees/acre) Between Groups 88.899 2 44.449 134.779 0.000 Within Groups 82.778 251 .330 Total 171.677 253 Transit balance of ridership flows Between Groups .350 2 .175 2.512 0.089 Within Groups 4.732 68 .070 Total 5.082 70 Health care opportunities (health care employees/ acre) Between Groups 332.513 2 166.257 80.229 0.000 Within Groups 520.143 251 2.072 Total 852.656 253 Population density (population/acre) Between Groups 23995.677 2 11997.839 191.116 0.000 Within Groups 15757.190 251 62.778 Total 39752.868 253 Access to culture and arts (corridor entertainment employees/acre) Between Groups 459.856 2 229.928 157.497 0.000 Within Groups 366.433 251 1.460 Total 826.288 253 Pedestrian environment (intersection density) Between Groups 174445.130 2 87222.565 97.357 0.000 Within Groups 224871.842 251 895.904 Total 399316.972 253 Pedestrian collisions per 100,000 pedestrians Between Groups 43.936 2 21.968 4.630 0.013 Within Groups 313.167 66 4.745 Total 357.103 68 Notes: P-Values less than 0.100 are considered statistically significant, indicating there are significant differences between the average values of each typology group for that variable (metric). Table G-3. ANOVA results comparing average metric scores for each outside-of-CBD transit corridor typology category.

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TRB's Transit Cooperative Research Program (TCRP) Research Report 187: Livable Transit Corridors: Methods, Metrics, and Strategies presents practical planning and implementation strategies to enhance livability in transit corridors. This Handbook provides a resource for planning practitioners, policy makers, and other stakeholders to measure, understand, and improve transit corridor livability.

The handbook provides a definition of transit corridor livability and a set of methods, metrics, and strategies—framed within a five-step visioning and improvement process—that communities can use to improve livability in their transit corridors. It includes a set of tools and techniques that can help in planning and building support for corridor improvements, screening alternatives in preparation for environmental review, identifying a corridor’s livability needs, and developing an action-oriented set of strategies for improving transit corridor livability and quality of life.

A spreadsheet-based Transit Corridor Livability Calculator tool is available for download. Instructions for using the Calculator tool are embedded within. Additional guidance in the form of a User Manual can be found in Appendix H of TCRP Research Report 187. To ensure the Calculator tool is fully-functional, make sure the tool's spreadsheet file and the TCRP Research Report 187 PDF file are both saved to the same directory folder on your computer.

Any digital files or software included is offered as is, without warranty or promise of support of any kind either expressed or implied. Under no circumstance will the National Academy of Sciences or the Transportation Research Board (collectively “TRB”) be liable for any loss or damage caused by the installation or operation of this product. TRB makes no representation or warranty of any kind, expressed or implied, in fact or in law, including without limitation, the warranty of merchantability or the warranty of fitness for a particular purpose, and shall not in any case be liable for any consequential or special damages.

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