A Time-Varying Coupling Analysis of Expressway Traffic Volume and Manufacturing PMI

Table 1

Unit root test of expressway passenger car, freight traffic, and manufacturing PMI.

Difference order	5% level	ADF test results
		Private car	Truck	Manufacturing PMI
Level	−1.94	2.5944	−0.3569	−0.6736
1st difference	−2.89	−5.9552	−3.9243	−12.4554