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

Table 11

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

	Measured and predicted PCI
	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	—			—			100	100
Early 2013	100	100		100	100		98.24	98.24	0
Early 2014	98.14	98.62	−0.489	97.59	97.59	0	93.35	93.05	0.323
Early 2015	90.57	90.53	0.039	90.89	91.46	−0.627	88.54	88.22	0.360
Early 2016	83.43	83.52	−0.104	86.79	85.54	1.444	81.89	83.47	−1.932
Early 2017	76.93	76.89	0.055	81.41	82.11	−0.866	77.86	76.88	1.254
Early 2018	70.86	70.86	0	77.31	77.33	−0.023	72.90	72.91	−0.019
Early 2019		65.23			73.74			68.01