I'm working on an isolated intersection with relatively high volumes and Prot/Perm left turns. I'm finding that prequently the LT sneakers from the previous phase block some or all of the protected LT phase for the cross-movement. I think that part of this problem is that a real sneaker is well into the intersection before making the turn, while a SimTraffic sneaker politely waits behind the stop bar before sneaking through. The time it then takes to clear the intersection blocks the cross movement.

Is there anything I can modify to fix this? Such as, limiting a movement to one sneaker. I think that artifically increasing the protected LT phase to allow for this would throw off the operation of the intersection.

Hi Robert,

Sorry to take a old post, but I think this will give the answer:

"Yes, this can be a problem with wide intersections, and it can be disruptive to the next up phases. As you have mentioned, the biggest factors to change would be the left turning speeds and yellow decel factors. You might also want to increase the speed for opposing right turn vehicles. These left turn sneakers are not allowed to enter the intersection until the intersection is clear. If a right turner is moving through the intersection slowly, then the lefts may wait even longer.

Right now, vehicles in SimTraffic will not enter the intersection and sit in the middle waiting for a gap. This would require a major change to the intersection approval logic, but it is something that is being investigated."

Thanks,

John.