Estimation of Annual Routine Maintenance Cost for Highway Tunnels

Table 4

The results of hierarchical regression analysis.

Variables	Block 1			Block 2			Block 3			Block 4
	Beta	t		Beta	t		Beta	t		Beta	t
Guanzhong	0.063	0.379	0.707	0.077	0.473	0.639	0.479	1.460	0.152	−8.857	−3.976	0.000
Shannan	−0.135	−0.808	0.423	−0.122	−0.796	0.430	0.318	1.248	0.219	3.067	4.088	0.000
lnAge	—	—	—	0.872	4.464	0.000	1.870	5.611	0.000	0.844	2.390	0.022
ln∑ESAL	—	—	—	−0.433	−1.954	0.057	−2.665	−3.836	0.000	−1.056	−1.520	0.137
lnAADT	—	—	—	—	—	—	0.752	1.145	0.259	1.737	2.547	0.015
lnESAL	—	—	—	—	—	—	1.436	2.413	0.020	1.265	1.820	0.077
PTT	—	—	—	—	—	—	0.572	2.370	0.023	−1.121	−2.047	0.048
lnAADTT	—	—	—	—	—	—	−0.740	−1.050	0.300	−0.442	−0.447	0.657
lnNT	—	—	—	—	—	—	—	—	—	8.640	3.587	0.001
PSLT	—	—	—	—	—	—	—	—	—	−0.631	−2.915	0.006
PLT	—	—	—	—	—	—	—	—	—	−0.295	−0.843	0.405
PMLT	—	—	—	—	—	—	—	—	—	−6.560	−4.696	0.000
lnNVF	—	—	—	—	—	—	—	—	—	−9.357	−4.501	0.000
lnNLF	—	—	—	—	—	—	—	—	—	−15.099	−4.084	0.000
R^2	0.031			0.390			0.546			0.768
Adjust R^2	−0.010			0.335			0.457			0.675
F	0.755			7.181			6.163			8.254
	0.475			0.000			0.000			0.000
ΔR^2	0.031			0.358			0.156			0.222
ΔF	0.755			13.214			3.529			5.560
	0.475			0.000			0.015			0.000