A Before-and-After Study of a Collision Risk Detecting and Warning System on Local Roads

Table 3

Odds ratio and treatment effect at site pairs A and B.

Site	Period	Conflict frequency	Odds ratio (OR)	Treatment effect (TE)
Experimental site A	Before	61	0.376	−0.624
	After	24
Control site A	Before	64
	After	67
Experimental site B	Before	149	0.450	−0.550
	After	64
Control site B	Before	154
	After	147