Monthly Attenuation Prediction for Asphalt Pavement Performance by Using GM (1, 1) Model

Table 12

Measured and predicted PQI for three typical roads of the trunk highway in Hunan Province.

	Measured and predicted PQI
	Line 1 measured value	Line 1 predicted value	Relative error (%)	Line 2 measured value	Line 2 predicted value	Relative error (%)	Line 3 measured value	Line 3 predicted value	Relative error (%)
Early 2012	—			—			97.59	97.59
Early 2013	97.4	97.4		96.96	96.96		96.07	96.07	0
Early 2014	95.33	95.33	0	95.32	95.32	0	92.44	92.35	0.100
Early 2015	89.85	89.86	−0.016	90.88	90.83	0.057	89.48	88.69	0.884
Early 2016	84.72	84.69	0.031	86.44	86.57	−0.150	83.85	85.70	−2.205
Early 2017	79.84	79.86	−0.025	82.40	82.30	0.117	81.01	80.04	1.200
Early 2018	75.25	75.25	0	78.41	78.43	−0.028	77.16	77.17	−0.010
Early 2019		70.92			74.60			73.29