Effect of automated enforcement 1 year after warning period
| Hourly vehicle volume* | Hourly violation rate* | Hourly high speed violation rate* | Mean violation speed† | Maximum violation speed* | Hourly mean speed* | |
| MD (95% CI) | MD (95% CI) | MD (95% CI) | MD (95% CI) | MD (95% CI) | MD (95% CI) | |
| Fixed | ||||||
| Time period | ||||||
| Warning | Ref | Ref | Ref | Ref | Ref | Ref |
| Citation year 1 | 29.0 (−16.6 to 74.7) | − 3.95 ( − 7.60 to 0.30) | −0.61 (−1.78 to 0.55) | 0.11 (0.023 to 0.20) | − 1.53 ( − 2.24 to 0.82) | − 1.07 ( − 1.62 to 0.52) |
| Citation year 2 | 11.9 (−0.54 to 24.3) | − 3.22 ( − 4.09 to 2.36) | − 0.32 ( − 0.54 to 0.10) | −0.050 (−0.17 to 0.075) | − 0.95 ( − 1.36 to 0.54) | −0.072 (−0.46 to 0.31) |
| Intercept | 439 (326 to 551) | 11.9 (7.36 to 16.44) | 1.83 (0.44 to 3.21) | 29.5 (29.1 to 29.9) | 35.7 (34.4 to 37.0) | 25.8 (24.7 to 26.9) |
| Random | ||||||
| Random parameters | ||||||
| Citation year 1 (SD) | 49.6 (26.2 to 93.9) | 4.7 (2.96 to 7.55) | 1.42 (0.69 to 2.94) | ‡ | 0.70 (0.39 to 1.28) | 0.64 (0.42 to 0.98) |
| Citation year 2 (SD) | 16.7 (8.6 to 32.3) | ‡ | ‡ | 0.131 (0.059 to 0.29) | 0.44 (0.24 to 0.81) | 0.45 (0.25 to 0.82) |
| Intercept (SD) | 146 (101 to 210) | 5.4 (3.50 to 8.39) | 1.45 (0.68 to 3.08) | 0.54 (0.33 to 0.88) | 1.62 (0.85 to 3.09) | 1.33 (0.83 to 2.13) |
| Correlation | ||||||
| Year 1 and year 2 | 0.080 (−0.50 to 0.61) | ‡ | ‡ | ‡ | 0.14 (−0.57 to 0.73) | −0.31 (−0.75 to 0.33) |
| Year 1 and intercept | 0.33 (−0.085 to 0.65) | −0.97 (−0.99 to 0.92) | −0.95 (−0.99 to 0.58) | ‡ | −0.15 (−0.62 to 0.40) | 0.23 (−0.45 to 0.74) |
| Year 2 and intercept | 0.029 (−0.52 to 0.56) | ‡ | ‡ | −0.72 (−0.97 to 0.38) | −0.86 (−0.97 to 0.49) | −0.24 (−0.80 to 0.54) |
| Residual (SD) | 143 (102 to 200) | 12.7 (10.69 to 15.2) | 7.70 (5.90 to 10.0) | 1.66 (1.54 to 1.79) | 3.68 (3.50 to 3.87) | 4.17 (3.66 to 4.75) |
Multivariable multilevel mixed linear regression to calculate MD and 95% CI.
Bolded results highlight findings whose 95% CI does not cross 0.
*Adjusted for day and quarter.
†Adjusted for day.
‡Not included in model.
MD, mean differences.