Since I am currently trying to deal with this. How about a timing entry page option to enter data in the cycle/offset/forceoff method?

Alternatives could be a converter tool or at least a good tutorial to show how to translate forceoffs into the Synchro timing entries. This could be used by someone like myself who primarily is doing LOS analyses and is not as familiar with controller programming.

Hi Dr. Q,

I am not personally aware of a FO calculater that is publically available. One of the reasons is that the FO value (used by 170, 2070 and others) is firmware specific. Depending on where the agency obtained the controller, the FO could vary.

For instance, I worked for a city that used 170 style controllers. To determine the splits, we had to know where the yeild point was referenced. Based on other settings, this could have been the start of the coordinated phase yellow or at the start of main street FDW. If we didn't get this set right, our splits would be completely off and the results would be skewed.

My best piece of advice on this is to work with the owner of the traffic signal. They will know how to convert FO's into splits and can give you the rules for their specific brand. Or, find out the vendor of the controller/firmware and they may have some documentation on this.

I do understand that this would be a very desirable feature in Synchro, but based on the differing ways this is done I'm just not sure it's doable/feasible.

Thanks,

John.

Thanks John. In my table it tells me the forceoff for phase 2 occurs at 0. Wouldn't that be a enough information to overcome the issue you mention about not knowing the reference point? I am a novice at this but that seems to indicate the yield point is the coordinated phase yellow.

In any event to use this style of entry, you could just make it a required input so that if you did have the yield point, you could enter the forceoff information directly.

My suggestion is merely to provide the option of the alternative format.

Hi Dr. Q,

I'm afraid that is not enough info to do it. It does tell me that Phase 2 is the coordinated phase. However, where is this zero point in reference to phase 2? Is it phase 2 yellow? Maybe phase 2 start of FDW? Possibly even some other point on phase 2. One doesn't want to assume where on phase 2 this is beginning.

Also, whether phases are leading/lagging can impact this calculation. Having dones these calculations for our specific controller software 100's if not 1000's of times, I'd be the first to agree that a nice calculater would be very useful. I used to setup spreadsheets to do this for me..... however, even then I had to check it very closely. It's not as easy as saying that phase 4 split is the phase 4 FO minus the phase 3 FO. What if phase 3 lags? What about the Y+AR times for the phases? What if 2 phases are coordinated? What if rest in walk is used? What if the ring and barrier structure has been modified? What if more than 8 phases are used?

The 170/2070 contoller can be thought of as a "generic" controller. Any agency could write there own operating software for these. So, I'm sorry to say that the operator of the signal would be the best source to get in touch with.

Maybe someone that reads these posts has a calculator and written rules on this that they could share. But, they would need to know the firmware used.

Thanks