I recently worked on a large housing development project where we introduced multiple new roads and neighborhood streets. As part of that, I implemented traffic using the path tool. But I found that where there was a bicycle path crossing the road there were unfortunate moments where the cars would pass straight through a cyclist, and as luck would have it, it would always happen when showing the model to clients. This generated some humor, but mostly drew attention to the shortcomings of the path drawing tool.
My initial thought (not knowing the specifics of the tool operation behind the scenes), is; would it be possible to create a more dynamic path tool which allowed a simple set of rules to be applied to the node system. For example, in the case of the afore mentioned cycle crossing, if the cyclist hits a programmed node, it checks to see if there is a vehicle in between two nodes on a specified path before continuing. This would allow for much more dynamic traffic animation. I can see it would require a complete overhaul of the system as a vehicle that has to wait Could cause another vehicle to back up behind it and other associated issues. But for the amount of times I've wished this feature existed I thought it was worth discussion here.