Capacity Increase through connectivity for the i-Roundabout and i-Turbo roundabout

Is a roundabout still a good solution in the era where ‘intelligent’ intersection control using vehicle connection (i-TLC), is in upswing? To answer this question, the capacity of ‘i-roundabouts’, where the infrastructure communicates with the vehicles (I2V), is determined analytically. The roundabouts considered are single-lane roundabouts and turbo roundabouts (a spiral multi-lane roundabout with reduced number of conflicts). A macroscopic approach explores the capacity gain that can be achieved by taking into account the necessary safety margins with regard to headways and gaps. Furthermore, it is assumed that by using I2V the speed, headway, and also the driving curve of the vehicles can be controlled. For roundabouts with speeds lower than 36 km/h, the conclusions are that:•On a single lane roundabout, roughly a doubling of the capacity can be achieved.•On a turbo roundabout the capacity gain can be surprisingly much higher (about a factor 2.5). This is due to the possibility of gap synchronization on the double-lane segments.