Is it possible to run 2 Simtraffic at the same time?

I like to compare before and after on the same screen.

Thanks.

Yes, but you cannot launch both from SYNCHRO. You can launch the first from SYNCHRO, but for the second (or more) you must run SimTraffic directly (I created a shortcut for this) and in that interface load an .SYn file which will then run. Depending on the speed of your machine and the complexity of your model, you may find that the model that does not have focus runs a bit less smoothly, but it is functional.