Study on the Operation Efficiency of Toll Roads in China from the Perspective of Scale Economy

Table 9

Parameter estimation results.

	(I)	(II)
	l_Debt	l_Debt
Tollway_Mile_	−7.009	−9.008
	(−3.53)	(−5.81)
Toll_int1	6.259	—
	(1.97)
Toll_int2	—	14.00
		(3.40)
Ratio_GDP	−0.165	−0.111
	(−6.27)	(−3.51)
l_cost_manage	1.473	1.278
	(13.41)	(7.79)
l_cost_maintain	0.115	0.0855
	(1.89)	(1.07)
Toll_Station_1	−8.027	−5.748
	(−3.72)	(−6.48)
_cons	3.870	4.305
	(25.66)	(15.34)
AR test	0.302	0.365
Hansen test	0.984	1
N	145	145

Note.Statistical significance at the 10% level; statistical significance at the 5% level; statistical significance at the 1% level. The t-statistics calculated with the standard error of heteroscedasticity are reported in brackets.