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. Author manuscript; available in PMC: 2017 Jun 1.
Published in final edited form as: J Transp Health. 2015 Sep 19;3(2):154–160. doi: 10.1016/j.jth.2015.08.007

Table 2. Regression model coefficients and average marginal effects.

Variables Probit Coefficient 95% Confidence Interval Average Marginal Effect
Access trip distance (miles) -0.80 -1.02, -.58 -0.12
Trip origin (1=home; 0=non-home) 0.55 .41, .68 0.08
Month (ref.=January)
February 0.10 -.13, .32 0.01
March 0.13 -.07, .33 0.02
April 0.21 -.19, .62 0.03
May -0.10 -.33, .13 -0.02
June -0.10 -.35, .14 -0.02
July 0.10 -.15, .35 0.01
August -0.04 -.25, .17 -0.01
September -0.05 -.28, .18 -0.01
October -0.12 -.32, .07 -0.02
November 0.05 -.19, .29 0.01
December -0.08 -.31, .15 -0.01
Income 0.02 -.02, .05 0.002
Household size 0.03 -.01, .07 0.004
Homeowner (1=yes; 0=no) 0.09 -.04, .23 0.01
Sex (1=male; 0=female) 0.05 -.04, .15 0.01
Hispanic (1=yes; 0=no) 0.06 -.07, .20 0.01
Born in USA (1=yes; 0=no) 0.06 -.06, .17 0.01
Possess driver's license (1=yes; 0=no) -0.01 -.14, .13 -0.001
Currently employed (1=yes; 0=no) -0.05 -.16, .06 -0.01
Disability (1=yes; 0=no) -0.20 -.35, -.04 -0.03
Education (ref.=not high school grad)
High school graduate -0.08 -.24, .08 -0.01
Some college credit -0.06 -.27, .14 -0.01
Associate or technical school degree 0.06 -.20, .33 0.01
Undergraduate degree -0.07 -.28, .13 -0.01
Graduate/professional degree -0.11 -.32, .10 -0.02
Age (years) -0.004 -.01, -.001 -0.001
Residence type (ref.=Single family detached)
Single family attached 0.01 -.16, .17 0.001
Mobile home 0.04 -.42, .51 0.01
Building with 2-4 units 0.03 -.13, .20 0.01
Building with 5-19 units 0.16 -.04, .36 0.02
Building with ≥ 20 units 0.17 -.004, .35 0.03
Day of week (ref.=Sunday)
Monday -0.04 -.21, .12 -0.01
Tuesday -0.10 -.27, .07 -0.02
Wednesday -0.12 -.29, .05 -0.02
Thursday -0.05 -.23, .14 -0.01
Friday 0.10 -.12, .33 0.01
Saturday 0.04 -.21, .28 0.01
Number of vehicles at household -0.05 -.12, .01 -0.01
Destination mode (ref.=local bus)
Express bus -0.13 -.34, .08 -0.02
Premium bus -0.20 -.87, .47 -0.03
Public transit shuttle 0.66 -.035, 1.36 0.07
Heavy rail -0.24 -.38, -.10 -0.04
Light rail -0.08 -.25, .08 -0.01
Street car -0.25 -.59, .09 -0.04
Trip number 0.03 .01, .05 0.004
Intercept 1.51 1.11, 1.90

Boldface text indicates significant parameter estimates (p≤0.05)