Would like to simulate Railroad crossing within 125 feet of signalized intersection. One single train runs through during the peak hour, but it does effect the intersection - and more specifically - Interstate On/Off ramps some 350 feet opposite the intersection from the RxR. Can this be done?

Hello,

Well the technical answer is that there is no way to do this. SimTraffic was not designed to model rail and traffic interactions.

Having said that, I know that some users have attempted to model this by putting in a dummy intersection to represent the rail crossing. This also has it's limitations. Some of these include:

* the longest cycle allowed is 900 seconds
* individual splits cannot be more then 360 seconds
* you can't control how an individual vehicle (train in this case) enters into the simulation (it is a stochastic process)

So, I guess if you wanted to try a pretimed controller that operates on a 900 second basis, you could try that. You probably need to put in a series of single ring phases to emulate this. Another option may be to try using the UTDF access in SimTraffic. But again, there are many pitfalls to this.

Maybe some of those that have had success at tricking the models to do this could weigh in?

Thanks,

John.

John Albeck
Trafficware

I've modelled rail interactions by using an un-coordinated semi-actuated dummy intersection. I set the actual roadway on "Max" recall with a small split (say 20 seconds). For the fake rail leg, I set the recall to "None", and use a long minimum green time - about 200-300 seconds. This simulates the pseudo-train, and holds main road traffic for the desired length when the random train arrives. You may also want to use a long leading detector on the rail leg, so that the train will trigger a green light and pass through the crossing without decelerating.

Since the main road is on max recall and the train is actuated, the main road will dwell in green in the abscence of a train.

Depending on the complexity, you can also use the cluster editor to interconnect the mock rail crossing with adjacent intersections to simulate limited mock pre-emption schemes.

- Jason

Thanks Jason!

That worked pretty well. I had to change the all-red phase to maximum (120 sec) to make it work, but it does exactly what I needed it to do. I appreciate your help.

Given Kutz,
Skagit County Public Works

Hi Given,

Glad to hear it helped!

- Jason