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

Table 5

Descriptive statistics for CO₂, CO, and emissions by intersection control type.

	Signalized; intersection	Roundabout	Total
Number of trips	202	194	396
CO2 (g):
Mean	59.62	51.75	55.76
SD	19.45	18.91	19.56
Median	59.88	45.46	53.05
(Q1–Q3)	(44.49–76.22)	(38.53–60.33)	(40.36–69.08)
CV%	32.6	36.5	35.1
CO (mg):
Mean	132.03	98.27	115.49
SD	130.73	82.53	110.95
Median	88.10	78.54	81.45
(Q1–Q3)	(39.48–181.67)	(37.30–133.49)	(39.20–155.69)
CV%	99.0	84.0	96.1
NOX (mg):
Mean	60.81	90.79	75.49
SD	45.23	55.53	52.66
Median	54.77	79.13	63.73
(Q1–Q3)	(23.96–86.56)	(46.98–127.64)	(35.94–107.35)
CV%	74.4	61.2	69.8