Table 4b Ordered Probit Model for Trip Occupancy: All Recreational Purposes

Table 4b
Ordered Probit Model for Trip Occupancy: All Recreational Purposes

Dependent variable: trip occupancy (all recreational purposes) Beta SE t-stat P-value
Constant 0.043 0.020 2.136 0.033
HH members per vehicle owned 0.349 0.006 57.435 0.000
Income per household member –9.77E-06 5.55E-07 –17.622 0.000
Population density 1.95E-07 8.11E-08 2.404 0.016
Weekend day indicator 0.341 0.014 24.810 0.000
SUV indicator 0.316 0.027 11.925 0.000
Pickup indicator –0.196 0.025 –7.802 0.000
Minivan indicator 0.524 0.019 27.929 0.000
μo 0.000 na na na
μ1 1.055 0.009 113.721 0.000
μ2 1.612 0.011 146.304 0.000
μ3 2.247 0.014 160.105 0.000

Note: Trip occupancy is grouped into 1, 2, 3, 4, and 5+ person levels.
na = Not applicable.

Log-likelihood function  
Constant only –38686.52
Convergence –35948.44
Pseudo-R2 0.071

Number of observations: 26,190 trips
Model form: Pr(Occupancy = 1) = Pr(μ* ≤ μo), Pr(Occupancy = 2) = Pr(μo ≤ μ* ≤ m1), Pr(Occupancy = 3) = Pr(μ1 ≤ μ* ≤ μ2), Pr(Occupancy = 4) = Pr(μ2 ≤ μ* ≤ μ3), and Pr(Occupancy ≥ 5) = Pr(μ3 ≤ μ*), where μ* = β′X + ε, and ε ~ Normal(0, 1)