School Travel Inequity between Students from Public and Private Schools in the City of Shenzhen, China

Table 4

Variables used in the model.

Variable	Type	Variable description and assumption
Individual demographic variables
Gender	dummy	0, girl; 1, boy. Boys are assumed to prefer motorized modes.
Grade	ordinal	Higher-grade students intend to use motorized travel.
Vehicle	dummy	1, household owns car(s); 0, no. Students from car-owning households are likely to be driven to school.
Individual travel features
Escort	dummy	1, picked up by parents; 0, no. Students who are escorted are likely to use a motorized travel mode.
Distance	continuous	Longer distance trips lead to more motorized usage.
School-level attribute variables
Public	dummy	0, private; 1, public
Location	dummy	0, peripheral; 1, central
School-level built environments
Catchment size	continuous	Large size encourages motorized travel modes.
Road density	continuous	Higher density promotes walk and cycling.
Street-crossing facilities	continuous	The number of street-crossing facilities within a school-centric buffer area with a radius of 2 km. More facilities benefit walking and cycling.
Street-crossing intervals	continuous	The average spacing distance between two nearby street-crossing facilities along all roads within a school-centric buffer area with a radius of 2 km. A smaller interval facilitates walking and cycling.
Bus station	continuous	More stations encourage travel by public transit.
Subway	dummy	0, no subway station within 1 km of the sampled school; 1, yes