Gap-accepteance parameters for roundabouts: a systematic review

European Transport Research Review

An Open Access Journal

Table 9 Summary results for follow – up headways at double-lane roundabouts - left entry lane

study name	subgroup within study	mean [s]	sample size	st error [s]	Z - value	Q	I² [%]
Gazzarri et al. [45]	A₁	3.10	145	0.08	39.29	22.32	19.36
Gazzarri et al. [45]	A₂	2.16	57	0.06	33.28	22.32	19.36
Gazzarri et al. [45]	A₃	2.77	59	0.09	29.55	22.32	19.36
Gazzarri et al. [45]	A₄	2.66	82	0.07	39.49	22.32	19.36
Gazzarri et al. [45]	A₅	2.56	124	0.06	43.19	22.32	19.36
Rodegerdts et al. [61]	B₁	3.10	1792	0.03	119.30	22.32	19.36
Rodegerdts et al. [61]	B₂	3.30	315	0.07	48.81	22.32	19.36
Rodegerdts et al. [61]	B₃	4.70	6	0.98	4.80	22.32	19.36
Rodegerdts et al. [61]	B₄	3.20	73	0.13	24.86	22.32	19.36
Rodegerdts et al. [61]	B₅	3.40	85	0.13	26.12	22.32	19.36
Rodegerdts et al. [61]	B₆	3.30	180	0.08	40.25	22.32	19.36
Rodegerdts et al. [61]	B₇	3.50	28	0.28	12.35	22.32	19.36
Zheng et al. [17]	C₁	3.10	698	0.05	63.00	22.32	19.36
Zheng et al. [17]	C₂	2.80	1768	0.03	98.11	22.32	19.36
Zheng et al. [17]	C₃	2.50	142	0.12	21.28	22.32	19.36
Zheng et al. [17]	C₄	2.50	233	0.07	38.16	22.32	19.36
Zheng et al. [17]	C₅	2.20	475	0.03	68.50	22.32	19.36
Zheng et al. [17]	C₆	2.10	100	0.08	26.25	22.32	19.36
Li et al. [71]	D₁	3.10	638	0.05	65.25	22.32	19.36
summary effect (random)		2.85		0.10	29.58	22.32	19.36