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

Table 2

The arithmetic average and t-test results of mean speed 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 mean speed 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	129.6	125.7(0.00)	111.4(0.00)	—	—	—
	5–10	126.1	124.8(0.00)	109.9(0.00)	—	—	—
	10–15	122.5	121.4(0.00)	106.3(0.00)	98.0(0.00)	—	—
	15–20	117.6	113.2(0.00)	102.1(0.00)	91.3(0.00)	91.4(0.00)	—
	20–25	111.6	106.3(0.00)	96.4(0.00)	86.5(0.00)	86.4(0.00)	90.6(0.00)
	25–30	100.6	99.6(0.56)	85.2(0.00)	—	—	—
Middle lane	5–10	116.9	110.2(0.00)	—	—	—	—
	10–15	115.1	111.3(0.00)	98.5(0.00)	—	—	—
	15–20	111.8	104.3(0.00)	96.7(0.00)	84.4(0.00)	82.0(0.00)	—
	20–25	105.1	97.8(0.00)	91.8(0.00)	84.0(0.00)	80.6(0.00)	87.0(0.00)
	25–30	85.7	88.9(0.18)	—	—	—	—
Right lane	5–10	98.8	92.5(0.00)	88.8(0.00)	—	—	—
	10–15	97.6	90.7(0.00)	88.6(0.00)	78.4(0.00)	—	—
	15–20	92.6	85.9(0.00)	86.0(0.00)	78.1(0.00)	72.7(0.00)	77.0(0.00)
	20–25	80.4	81.3(0.67)	—	—	—	—