Analyzing the Safety Impacts of Variable Speed Limit Control on Aggregated Driving Behavior Based on Traffic Big Data

Table 3

The arithmetic average and t-test results of ASD within different density intervals under different speed limits on different lanes (“—” means the sample size is less than 15).

Lane	Density (veh/km)	The arithmetic average of ASD under different speed limits (km/h)
		No VSL	120 km/h	100 km/h	80 km/h	60 km/h	50 km/h
Left lane	0–5	8.89	7.01(0.01)	6.85(0.02)	—	—	—
	5–10	6.54	6.23(0.08)	5.88(0.00)	—	—	—
	10–15	5.13	4.97(0.14)	4.53(0.00)	4.41(0.03)	—	—
	15–20	4.20	3.90(0.00)	3.53(0.00)	3.62(0.00)	4.11(0.73)	—
	20–25	3.61	3.24(0.00)	3.12(0.00)	2.95(0.00)	3.15(0.00)	3.19(0.03)
	25–30	3.10	2.87(0.00)	2.90(0.03)	—	—	—
Middle lane	5–10	7.80	7.78(0.97)	—	—	—	—
	10–15	6.35	5.92(0.00)	4.55(0.00)	—	—	—
	15–20	5.37	4.69(0.00)	3.82(0.00)	3.44(0.00)	5.03(0.00)	—
	20–25	4.43	3.62(0.00)	3.19(0.00)	3.38(0.00)	3.26(0.00)	3.67(0.01)
	25–30	3.32	2.86(0.00)	—	—	—	—
Right lane	5–10	10.19	8.75(0.01)	5.63(0.00)	—	—	—
	10–15	7.91	6.33(0.00)	4.57(0.00)	3.47(0.00)	—	—
	15–20	6.02	4.48(0.00)	3.55(0.00)	3.10(0.00)	3.64(0.00)	4.15(0.01)
	20–25	4.21	3.58(0.01)	—	—	—	—