VERIFIED SOLUTION i
Resolve Roundabout gridlock in Paramics model
Vehicles gridlock around a roundabout, causing the whole network to seize up. All the gridlocked vehicles seems to be in Braking mode, at zero speed, with a tiny target headway that’s much less than their actual headway, but the program logic won’t let them inch forward to make space for the vehicle behind to exit the roundabout.
This could be caused due to the fact that when links are short, vehicles can become confused as to which link they’re on, causing unrealistic behavior (stopping on a roundabout when/where there is no need to) which causes the gridlock (or the repeated circling of a roundabout).
UPDATED: October 5, 2017
This is identified as a defect in Paramics and not fixed hitherto. Following workaround can be tried:
- Set the headway factor low on the roundabout links so as to encourage the vehicles to bunch up
- Add roundabout in spatial tests.
- Replace the smallest roundabouts with all-way give-ways.
- Lengthen the links on the circulating carriageway of those roundabouts that we’re modelling as a set of give-way junctions (more distance on the link red-to-white, less distance at the nodes white-to-red).
Product Feature: Modeller
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