Descriptive statistics of hourly outcomes during school travel hours (means and SD)
| Total hours | Hours with violations | Vehicle volume | Violation rate (per 1000 vehicles) | Violation rate>35 MPH (per 10 000 vehicles) | Mean violation speed (MPH) | Max violation Speed (MPH) | Mean speed (MPH) | |
| N | % | Mean (SD) | Mean (SD) | Mean (SD) | Mean (SD) | Mean (SD) | Mean (SD) | |
| Camera | ||||||||
| Warning | 1831 | 29 | 498 (232) | 13.0 (27.2) | 1.92 (15.5) | 29.4 (1.4) | 35.5 (4.3) | 25.7 (3.9) |
| Citation | 24 669 | 38 | 480 (216) | 6.4 (11.5) | 0.96 (6.97) | 29.5 (1.7) | 33.8 (4.0) | 24.2 (4.5) |
| P values* | 0.296 | <0.001 | 0.262 | 0.227 | 0.3231 | <0.001 | ||
| Day | ||||||||
| Monday | 5015 | 38 | 461 (208) | 7.0 (13.0) | 1.14 (8.11) | 29.6 (1.7) | 34.0 (4.0) | 24.5 (4.4) |
| Tuesday | 5498 | 37 | 474 (219) | 6.2 (12.6) | 0.97 (8.92) | 29.4 (1.8) | 33.7 (4.2) | 24.2 (4.5) |
| Wednesday | 5563 | 36 | 480 (217) | 6.4 (12.7) | 0.83 (6.10) | 29.5 (1.7) | 33.8 (4.1) | 24.2 (4.4) |
| Thursday | 5385 | 39 | 486 (220) | 6.9 (13.4) | 1.10 (7.78) | 29.5 (1.7) | 33.9 (4.0) | 24.1 (4.5) |
| Friday | 5039 | 38 | 497 (220) | 7.1 (13.6) | 1.01 (7.50) | 29.5 (1.7) | 34.0 (3.9) | 24.3 (4.5) |
| <0.001 | <0.001 | 0.190 | 0.001 | 0.0231 | <0.001 | |||
| Time | ||||||||
| AM | 12 700 | 37 | 415 (195) | 7.6 (14.7) | 1.21 (9.23) | 29.6 (1.7) | 34.1 (3.9) | 24.3 (4.8) |
| PM | 13 800 | 38 | 538 (220) | 5.9 (11.3) | 0.82 (6.01) | 29.4 (1.7) | 33.7 (4.1) | 24.3 (4.1) |
| 0.058 | 0.466 | 0.709 | 0.217 | 0.390 | 0.819 | |||
| Quarter | ||||||||
| Fall | 11 945 | 34 | 490 (227) | 6.3 (14.6) | 0.97 (8.27) | 29.5 (1.8) | 33.7 (4.1) | 24.6 (4.3) |
| Winter | 7990 | 40 | 463 (210) | 7.2 (12.1) | 1.10 (7.65) | 29.5 (1.6) | 34.1 (3.9) | 24.2 (4.5) |
| Spring | 6565 | 40 | 480 (207) | 6.8 (11.2) | 0.96 (6.73) | 29.5 (1.7) | 33.9 (3.9) | 23.7 (4.6) |
| <0.001 | 0.0428 | 0.185 | 0.631 | 0.150 | <0.001 |
*P values were calculated from univariate linear mixed effects models and robust SEs or generalised linear mixed effects models as described in Methods section.