Table 6.

Project index reference at each stage of the bus ride.

	The number of line	The car environment	The number of people in the car	Are there any seats available?	Do you need to ask?
Stage 1	1 person	Quiet	0	Yes, it is completely empty	No
Stage 2	6 people	A bit noisy	5 people	Yes, more seats	According to the choice of subjects
Stage 3	I1 people	More noisy	10 people	Yes, there are fewer vacancies	Yes
Stage 4	16 people	Very noisy	25 people	There is no vacancy	According to the situation on the bus