I've been told that Synchro 6 does not meet HCM standards...is this true?

Eric
Caltrans

Hi Eric,

Synchro does have an HCM Signal Report that more closely follows the methods of the HCM. However, even this report performs some items for you. I don't know if I'd say this voids a "standard". I assume standard here means a 100% replication of the HCM worksheets. This is where Synchro veers.

Here are the main items that Synchro attempts to do that would make it different than the HCM worksheets:

* Synchro uses dual ring - HCM is single ring control. You could code single ring in Synchro if you wish.

* Synchro calculates the Progression Factor (PF) based on upstream arrivals. In the HCM, the user enters an Arrival Type (AT) and this looks up a PF. So, Synchro requires upstream signals to be coded. There is no way to input an AT (1 to 6) in Synchro.

* If you have an actuated movement, Synchro determines an effective green. The HCM requests that the user enters the effective green (not the mins, maxes, extensions, etc). You could mimic this in Synchro by using a pretimed control. Then, enter the actuated times as pretimed splits.

* Synchro computes a RTOR saturation flow adjustment. It then converts this to a volume RTOR (vRTOR). In the HCM, the user enters the vRTOR. To mimic this, the user could uncheck RTOR and then subtract the user determined vRTOR from the right turn volume.

Thanks,

John.

PS - the above comments are true to version 7 also.