The Impact of Truck Proportion on Traffic Safety Using Surrogate Safety Measures in China

Table 2

The data of collected parameters after preliminary statistics in different periods.

Variables	Period (min)	Mean	Std.	Max.	Min.
Truck proportion	5	0.335	0.184	1	0.044
	10	0.326286	0.165	0.983	0.128
	15	0.324583	0.162	0.968	0.107
Traffic volume	5	167.186	38.628	321	108
	10	330.077	70.590	546	217
	15	491.052	99.200	750	329
Average speed (km/h)	5	89.173	12.572	124.223	43.318
	10	89.597	11.957	120.473	49.555
	15	89.358	12.137	121.737	44.407
Speed difference (km/h)	5	24.461	8.976	49.971	0.153
	10	24.547	8.152	45.738	0.426
	15	24.533	7.804	43.796	0.127
Speed standard deviation	5	18.508	4.269	45.924	7.271
	10	18.799	3.885	35.892	7.867
	15	18.875	3.676	31.652	8.145
85%V–15%V	5	38.784	10.711	68.957	11.923
	10	39.963	10.139	64.489	12.457
	15	40.377	9.810	64.067	14.971
Variation coefficient	5	0.212	0.058	0.394	0.090
	10	0.214	0.053	0.348	0.095
	15	0.216	0.053	0.371	0.136
Number of lane changes	5	1.708	1.804	10	0
	10	3.386	3.047	17	0
	15	5.072	4.283	18	0