Table 4 Estimated Demand Equation
Table 4
Estimated
Demand Equation
Dependent variable: D(LTRAFFIC)
Estimation method: weighted least squares
Total system (unbalanced) observations: 990
| Variable | Coefficient | Std. error | t-statistic | P-value |
|---|---|---|---|---|
| D(LGDP) | 0.8901 | 0.0409 | 21.7605 | 0.0000 |
| D(LPGAS) | –0.3367 | 0.0153 | –22.0050 | 0.0000 |
| D(LTRAFFIC(-1)) | 0.3659 | 0.0158 | 23.1470 | 0.0000 |
| D(LTOLL1) | –0.2092 | 0.0177 | –11.813 | 0.0000 |
| D(LTOLL2) | –0.3707 | 0.0147 | –25.248 | 0.0000 |
| D(LTOLL3) | –0.4449 | 0.0225 | –19.801 | 0.0000 |
| D(LTOLL4) | –0.8286 | 0.0844 | –9.8179 | 0.0000 |
| D(Z1) | –0.0517 | 0.0260 | –1.9919 | 0.0467 |
| D(Z2) | –0.0689 | 0.0239 | –2.8782 | 0.0041 |
| D(Z3) | –0.0718 | 0.0246 | –2.9179 | 0.0036 |
| D(Z4) | –0.0519 | 0.0263 | –1.9745 | 0.0486 |
| D(Z5) | 0.1549 | 0.0396 | 3.9136 | 0.0001 |
| D(Z6) | 0.1690 | 0.0364 | 4.6466 | 0.0000 |
| D(Z7) | 0.1196 | 0.0583 | 2.0507 | 0.0406 |
| D(Z8) | –0.0679 | 0.0219 | –3.1035 | 0.0020 |
| D(Z9) | –0.0623 | 0.0201 | –3.1029 | 0.0020 |
| D(Z10) | –0.0656 | 0.0286 | –2.2911 | 0.0222 |
| D(Z11) | –0.0425 | 0.0227 | –1.8689 | 0.0619 |
| D(Z12) | –0.0550 | 0.0250 | –2.2015 | 0.0279 |
| D(Z13) | 0.0746 | 0.0251 | 2.9698 | 0.0031 |
| D(Z14) | –0.0337 | 0.0201 | –1.6798 | 0.0933 |
| D(Z15) | 0.0626 | 0.0202 | 3.0952 | 0.0020 |
| D(Z16) | –0.0360 | 0.0188 | –1.9175 | 0.0555 |
| D(Z17) | 0.0498 | 0.0188 | 2.6367 | 0.0085 |
| D(Z18) | 0.0445 | 0.0192 | 2.3154 | 0.0208 |
| D(Z19) | 0.0404 | 0.0153 | 2.6397 | 0.0084 |
| D(Z20) | 0.0529 | 0.0134 | 3.9563 | 0.0001 |
| D(Z21) | 0.1698 | 0.0433 | 3.9163 | 0.0001 |
| D(Z22) | 0.0812 | 0.0163 | 4.9712 | 0.0000 |
| D(Z23) | 0.0822 | 0.0207 | 3.9686 | 0.0001 |
| D(Z24) | 0.1379 | 0.0187 | 7.3903 | 0.0000 |
| D(Z25) | –0.1366 | 0.0488 | –2.7992 | 0.0052 |
| D(Z26) | 0.0864 | 0.0177 | 4.8746 | 0.0000 |
| D(Z27) | 0.0751 | 0.0175 | 4.2902 | 0.0000 |
| D(Z28) | 0.0451 | 0.0206 | 2.1897 | 0.0288 |
| R2 (average for the motorway sections) | 0.74 | |||
| First order autocorrelation coefficient (pooling estimation for the motorway sections) | 0.019 |
Note: All variables are defined in first differences (D) of the logarithm (L). GDP = gross domestic product; PGAS = gasoline price; TRAFFIC = average daily traffic volume; TOLL1 = low toll elasticity group; TOLL2 = low-medium toll elasticity group, TOLL3 = medium-high toll elasticity group; TOLL4 = high toll elasticity group; D(Z1) to D(Z28) = first differences of the dummy variables to account for changes in the road network.