Group Gap Acceptance: A New Method to Analyze Driver Behavior and Estimate the Critical Gap at Multilane Roundabouts

Table 1

Summary of past studies.

Author(s)	Year	Analysis method	Critical gap (s)	Type of roundabout	City, country
Flannery and Datta [3]	2007	Maximum likelihood method	3.94	1-lane	Florida and Maryland, USA
Xu and Tian [4]	2008	Maximum likelihood method	4.8		California, USA
Mensah et al. [5]	2010	Raff’s method	2.55		Maryland, USA
Fitzpatrick et al. [6]	2013	Raff’s method	2.2		Massachusetts, USA
Xu and Tian [4]	2008	Maximum likelihood method	L: 4.70/; R: 4.40	2-lane	California, USA
Guo [7]	2010	Raff’s method	2.91		Dalian, China
		Revised Raff’s method	2.78
		Maximum likelihood method	2.65
		Ashworth method	3.2
Kusuma and Koutsopoulos [8]	2011	Maximum likelihood method	3.58		Stockholm, Sweden