Bus Travel Time Deviation Analysis Using Automatic Vehicle Location Data and Structural Equation Modeling

Table 1

Exogenous and endogenous variables for SEM models.

	Name	Notation	Description
Endogenous variables	Dwell time		Difference between actual departure time () and actual arrival time () for bus trip at the bus stop , that is,
	Travel time deviation		Deviation of actual travel time () from scheduled travel time () for bus trip on the bus route segment , that is, , where
	Accumulated delay		Sum of travel time deviation on the upstream segments from 1 to , that is,
	Number of traffic signals		Number of traffic signals on the bus route segment
	Number of access connections		Number of access connections on the bus route segment
Exogenous variables	Segment length		Length of the bus route segment between adjacent bus stops
	Departure delay		Deviation of actual departure time () from scheduled departure time () at the bus terminal for the bus trip , that is,
	Percentage of completed trip		Percentage of travel time that buses spent on upstream segments, that is,