Table 1

Descriptive statistics of hourly outcomes during school travel hours (means and SD)

Total hoursHours with violationsVehicle volumeViolation 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
 Warning183129498 (232)13.0 (27.2)1.92 (15.5)29.4 (1.4)35.5 (4.3)25.7 (3.9)
 Citation24 66938480 (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<0.0010.2620.2270.3231<0.001
Day
 Monday501538461 (208)7.0 (13.0)1.14 (8.11)29.6 (1.7)34.0 (4.0)24.5 (4.4)
 Tuesday549837474 (219)6.2 (12.6)0.97 (8.92)29.4 (1.8)33.7 (4.2)24.2 (4.5)
 Wednesday556336480 (217)6.4 (12.7)0.83 (6.10)29.5 (1.7)33.8 (4.1)24.2 (4.4)
 Thursday538539486 (220)6.9 (13.4)1.10 (7.78)29.5 (1.7)33.9 (4.0)24.1 (4.5)
 Friday503938497 (220)7.1 (13.6)1.01 (7.50)29.5 (1.7)34.0 (3.9)24.3 (4.5)
<0.001<0.0010.1900.0010.0231<0.001
Time
 AM12 70037415 (195)7.6 (14.7)1.21 (9.23)29.6 (1.7)34.1 (3.9)24.3 (4.8)
 PM13 80038538 (220)5.9 (11.3)0.82 (6.01)29.4 (1.7)33.7 (4.1)24.3 (4.1)
0.0580.4660.7090.2170.3900.819
Quarter
 Fall11 94534490 (227)6.3 (14.6)0.97 (8.27)29.5 (1.8)33.7 (4.1)24.6 (4.3)
 Winter799040463 (210)7.2 (12.1)1.10 (7.65)29.5 (1.6)34.1 (3.9)24.2 (4.5)
 Spring656540480 (207)6.8 (11.2)0.96 (6.73)29.5 (1.7)33.9 (3.9)23.7 (4.6)
<0.0010.04280.1850.6310.150<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.