Table 2.

RDD values for traffic volumes and air pollutants in four cities

City	Private traffic	Public traffic	NO2	O3
Madrid	−0.728***	−0.813***	−0.138***	0.118***
	(0.159)	(0.165)	(0.043)	(0.044)
Barcelona	−0.903***	−0.987***	−0.118***	0.163***
	(0.189)	(0.506)	(0.034)	(0.041)
Los Angeles	−0.775***	−0.856***	−0.113**	0.084**
	(0.189)	(0.177)	(0.047)	(0.033)
Providence	−0.303*	−0.492***	−0.094***	0.104**
	(0.155)	(0.160)	(0.032)	(0.040)

The symbols *, **, and *** denote significance at the 10%, 5%, and 1% levels, respectively