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Re: Pedestrians aren't the only ones who matter.

Posted by Stephen Bauman on Tue Jan 10 10:11:31 2017, in response to Re: Pedestrians aren't the only ones who matter., posted by JerBear on Tue Jan 10 08:36:24 2017.

The problem with logic is that it works with complicated but not with complex problems.
The reason traffic engineers have complex computer models is because you can't just reason out an answer and predict how the road will function unless you're talking about a 2-lane road in Iowa with few intersections.

NYCDOT uses a proprietary simulation model (Aimsum). Its assumptions are not known. Only the results, chosen by NYCDOT, are known. There is very little the public can determine, given these conditions. Occasionally, there are glimpses that the simulation isn't quite accurate.

One such instance concerns the time savings to be gained by the Woodhaven Blv SBS project, given in a May 2016 presentation. It compares before/after running times between Jamaica and Metropolitan Aves. The before/after comparison is 12.9 vs. 7.8 minutes.

It would appear that nobody bothered checking the Q52/Q53 schedule to see how accurate the simulation is at predicting the then current situation. Such a check would have revealed that the then current running time (May 2016) between these two stops to be 6.3 minutes. No observer should have much faith in the projected time savings from the simulation, until any simulation more accurately predicts the current state.


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