Evaluation of Roundabout Safety Performance through Surrogate Safety Measures from Microsimulation

Table 3

Geometric design and behavioural parameters of every roundabout category.

Basic Parameter	Single-Lane Roundabout	Double-Lane Roundabout	Turbo Roundabout
outer diameter[m]	39.00	41.00	40.00
ring width [m]	7.00	9.00	4.50 ()
entry-lane width [m]	3.75	3.50	3.50
exit-lane width [m]	4.50	4.50	4.50
Tci [s]	-	4.159 (3.898, 4.420)	3.60
Tce [s]	4.274 (4.051; 4.498)	3.822 (3.562; 4.082)	3.91
Tfi [s]	-	2.853 (2.665, 3.043)	2.26 (2.110, 2.411)
Tfe[s]	3.103 (2.957; 3.248)	2.717 (2.569, 2.867)	2.13 (1.981,2.287)

Note: inside lane width; outside lane width; 95% confidence interval; on field collected by Fortuijn [22].