There are two ways to deal with this situation
a) override this type of junction deadlock by setting the option --ignore-junction-blocker TIME (vehicles will ignore the blocked junction after waiting for TIME)
b) figure out why the blockage happens. Possible causes are:
- insufficient clearance time (i.e. all-red-time) between phases relative to the size of the junction
- most likely problem: signal plan with permissive green 'g' and no added 'G' phase for vehicles with permissive left turn (left turning vehicles wait on the junction and have insufficient time to finish their turn before the next phase starts).
- a developing jam on the outbound edge that starts during a green phase and leaves some vehicles "stranded" on the junction when their phase runs out
- misconfigured signal plan (that gives 'G' to conflicting streams)
- outdated version of SUMO with implementation bugs
- as of yet undiscovered implementation bugs in the latest SUMO release
If you cannot figure it out / suspect the latter, please send in a minimal failing example.
regards,
Jakob
