Macroscopic Traffic State Estimation: Understanding Traffic Sensing Data-Based Estimation Errors

Table 1

Interpretation of the four clusters based on the cluster centroids and the error distribution characteristics for probe and loop-detector data-based estimates per cluster.

		Clusters
		1	2	3	4
		Jam inflow	Free flow	Congestion	Jam outflow
Cluster; centroids	[km/h]	58.5	96.0	23.8	47.7
	[veh/km]	87.1	51.3	187.4	108.9
	[veh/h]	4596	4878	4369	5049
	[km/(km h)]	−0.108	−0.001	−0.002	0.096
	Num. obs.	601	8424	1889	630
Probe; data; error; char.	Mean	0.55	−0.04	0.01	0.05
	Variance	784.0	87.9	48.8	455.9
	Skewness	0.06	0.72	−1.48	−0.19
	Kurtosis	2.99	6.91	17.00	2.67
	JB test	1	1	1	1
	Num. obs.	31187	248461	213184	41982
Loop-detector; data; error; char.	Mean	15.17	−0.08	−0.40	−31.23
	Variance	115.2	20.1	15.4	107.5
	Skewness	0.51	1.76	−0.17	1.03
	Kurtosis	3.43	19.50	8.75	5.25
	JB test	1	1	1	1
	Num. obs.	601	8424	1889	630