Good Afternoon,

I have a question related to Synchro's calculation of network delay. I have a 5-intersection corridor which is being evaluated, and one of the intersections is currently unsignalized. I am getting an error at the unsignalized intersection for the side street delay, queue length, and LOS due to a large number of vehicles on the major street (Synchro calculated the capacity of the minor streets to be zero). I understand from other posts that this is a known issue with Synchro (the movement is over capacity so values cannot be calculated).

An issue arises when I compare the network delay for the unsignalized scenario with that of a signalized scenario. Intuitively, when you implement a signal, the network delay will increase due to impacting vehicles on the major street. However, in my case the addition of a signal reduces the network delay by approximately 75%. It should be noted that the side-street turning volumes are just a fraction of the volumes on the major street.

How is the network delay calculated when minor approach delays are returned as an error? The network delay for the unsignalized scenario appears to be greatly overestimated, and I have been unable to find any information as to how the calculations are done.

Thanks in advance.

-Jason