Table 3.
Unit root test results of panel data.
| Variables | LLC |
ADF- Fisher |
Results | ||
|---|---|---|---|---|---|
| Statistic | p valuea | Statistic | p valuea | ||
| Traffic accident casualties | −15.7195 | <0.0001 | 142.354 | <0.0001 | stability |
| D (GDP) | −8.09038 | <0.0001 | 93.1695 | 0.0064 | stability |
| New road mileage | −17.4677 | <0.0001 | 216.705 | <0.0001 | stability |
| D (Traffic investment) | −10.7701 | <0.0001 | 197.593 | <0.0001 | stability |
| Newly increased population | −6.97773 | <0.0001 | 130.266 | <0.0001 | stability |
| New vehicle ownership | −11.2114 | <0.0001 | 155.425 | <0.0001 | stability |
D(*) denotes first-order difference.
LLC: Levin, Lin & Chut, GDP: gross domestic product.
a
Indicates that asymmetric normality is used to calculate probability in Levin, Lin & Chut test, and asymptotic chi-square distribution is used to calculate probability in ADF-Fisher test.