Table 4.
Random-intercept factional logit regression results on tract-level percentage workers taking public transportation to work (PTTW).
| Rural tracts |
Urban tracts |
t-test for differencea | |||
|---|---|---|---|---|---|
| Variables | Marginal effects | p-value | Marginal effects | p-value | p-value |
| Tract pop. density (1000/sq mile) | -0.032 | 0.0003 | 0.025 | <.0001 | 0.0504 |
| Median housing age | 0.000 | 0.6238 | 0.066 | <.0001 | <.0001 |
| Tract intersection density/sq mile | 0.001 | 0.0003 | 0.002 | <.0001 | 0.0966 |
| Tract % area green canopy | 0.002 | 0.0005 | -0.007 | <.0001 | 0.0013 |
| Average distance to 7 closest parks | 0.001 | 0.0934 | -0.166 | <.0001 | <.0001 |
| EPA poor air quality status | 0.039 | 0.3541 | 1.277 | <.0001 | 0.2481 |
| Tract med. income (in $1000) | -0.003 | 0.0024 | 0.004 | 0.0127 | 0.0004 |
| Tract Gini coefficient (%) | -0.009 | <.0001 | -0.012 | 0.002 | 0.0013 |
| Tract med. housing value (in $10,000) | 0.009 | <.0001 | 0.001 | 0.5803 | <.0001 |
| Tract % housing owner-occupied | -1.346 | <.0001 | -7.841 | <.0001 | 0.2741 |
| County total crime/1000 people | -0.002 | 0.0272 | 0.011 | 0.0604 | 0.0258 |
| Tract % 16+ commuting 1 hour+ | 0.020 | <.0001 | 0.118 | <.0001 | 0.007 |
| Tract % living in college dorms | -0.010 | <.0001 | -0.020 | <.0001 | 0.0065 |
| Tract % living in military quarters | -0.008 | 0.0999 | -0.044 | 0.002 | 0.8553 |
| Tract median age | -0.009 | <.0001 | 0.000 | 0.9521 | 0.1674 |
| Tract % Asians | 0.004 | 0.2138 | 0.045 | <.0001 | 0.0067 |
| Tract % Blacks | 0.002 | 0.0048 | 0.056 | <.0001 | <.0001 |
| Tact % Hispanics | -0.006 | <.0001 | 0.038 | <.0001 | <.0001 |
| Tract % foreign-born | 0.017 | <.0001 | -0.008 | <.0001 | <.0001 |
| Tract % 25+ college educated | 0.004 | 0.0007 | 0.046 | <.0001 | 0.5868 |
| R2 | 0.10 | 0.69 | |||
| R2 environmental variables only | 0.01 | 0.56 | |||
| R2 non-environmental variables only | 0.10 | 0.51 | |||
Note: The random-intercept fractional logit models were estimated with PTTW prevalence specified between 0 and 1. However, the marginal effects were multiplied by 100 for ease of presentation. As an example, a marginal effect of 0.025 for tract population density should be interpreted as: On average, an increase of 1000 people/ sq miles in the tract was associated with a 0.025% increase in prevalence of PTTW in urban tracts.
a
t-tests evaluated the significance of the difference between rural tracts and urban tracts.