Journal of Advanced Transportation / 2018 / Article / Tab 7

Research Article

Before-and-After Field Investigation of the Effects on Pollutant Emissions of Replacing a Signal-Controlled Road Intersection with a Roundabout

Table 7

Two-sample biaspect permutation tests of emissions of CO2 (g), CO (mg), and (mg) between signal control and roundabout, with Bonferroni-Holm adjustment for multiple testing.

Trip conditionSignalized intersectionRoundaboutTest for location, p value Test for variability, p valueOverall test,
p value
Overall adjusted p value
NumberMean ± SDNumberMean ± SD

CO2 (g):
Morning/Off-peak/Trip B2464.5 ± 16.52849.1 ± 10.60.000250.000250.000250.00150
Afternoon/Peak/Trip A4353.5 ± 19.53141.3 ± 9.90.002650.001050.001650.00825
Morning/Peak/Trip A3256.0 ± 21.43945.2 ± 9.90.005950.001650.003050.01220
Morning/Off-peak/Trip A2548.7 ± 18.92740.3 ± 8.70.042750.013950.024350.07305
Afternoon/Peak/Trip B4568.8 ± 16.53076.6 ± 23.60.099640.059640.07704
Morning/Peak/Trip B3363.2 ± 17.03957.2 ± 18.4
CO (mg):
Afternoon/Peak/Trip A43178.3 ± 161.43189.9 ± 64.90.004750.004150.004350.02610
Morning/Peak/Trip A32184.5 ± 166.539108.3 ± 74.60.008850.003150.005150.02575
Afternoon/Peak/Trip B45128.4 ± 118.93070.5 ± 59.00.012250.030050.017350.06940
Morning/Off-peak/Trip A2565.2 ± 64.02792.2 ± 89.8
Morning/Off-peak/Trip B2467.5 ± 57.52886.2 ± 57.8
Morning/Peak/Trip B33123.4 ± 95.439129.2 ± 115.2
NOX (mg):
Morning/Peak/Trip A3238.4 ± 26.13966.7 ± 40.00.000950.000850.000750.00450
Afternoon/Peak/Trip B4594.0 ± 52.430135.1 ± 53.40.002050.002250.001850.00925
Morning/Off-peak/Trip A2544.2 ± 34.92786.0 ± 50.20.001650.003150.002050.00820
Morning/Off-peak/Trip B2461.5 ± 32.128100.9 ± 57.60.003450.003250.003350.01005
Morning/Peak/Trip B3345.0 ± 38.83981.3 ± 64.10.006450.008650.007350.01470
Afternoon/Peak/Trip A4364.2 ± 45.43185.1 ± 41.20.045840.080240.08024

value greater than 0.10.