Gap-accepteance parameters for roundabouts: a systematic review

European Transport Research Review

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Table 11 Comparison between summary effect (random) and mean values for critical headways

study name	roundabout	entry	entry lane	circulating lane	mean values [s]
Gazzarri et al. [45]	single-lane				3.86
Rodegerdts et al. [61]	single-lane				4.30
Zheng et al. [17]	single-lane				4.77
Fortuijn [44]	single-lane				3.22
summary effect (random)					4.27
Gazzarri et al. [45]	double-lane			outer	3.69
Rodegerdts et al. [61]	double-lane			outer	4.26
Zheng et al. [17]	double-lane			outer	3.49
Fortuijn [44]	double-lane			outer	2.89
summary effect (random)					3.82
Gazzarri et al. [45]	double-lane			inner	3.88
Rodegerdts et al. [61]	double-lane			inner	4.77
Zheng et al. [17]	double-lane			inner	4.01
Li et al. [71]	double-lane			inner	4.30
Fortuijn [44]	double-lane			inner	3.16
summary effect (random)					4.16
Fortuijn [44]	turbo	major	left		3.60
summary effect (random)					3.60
Fortuijn [44]	turbo	major	right		3.87
summary effect (random)					3.91
Fortuijn [44]	turbo	minor	left	inner	3.19
summary effect (random)					3.20
Fortuijn [44]	turbo	minor	left	outer	3.03
summary effect (random)					3.07
Fortuijn [44]	turbo	minor	right		3.74
summary effect (random)					3.83