stereopticon

Incorporating Dynamic Wait Times Into Shortest Path Analysis

Discussion created by stereopticon on Jul 31, 2011
Latest reply on Apr 25, 2012 by pstevens-esristaff
Hello all,

I am doing a transit accessibility research project that finds the shortest-time path between an origin and destination point using a bus network. The basic network dataset configuration is similar ESRI's Paris Multimodal network tutorial, but there's a twist: it is necessary to include waiting times at a stop for the next bus in the solver's calculations. The individual's arrival time at the stop is determined by their departure time and the distance they travel, so that arrival time is a variable that must be used to calculate the wait until the next available bus by comparing it to either a fixed headway or a list of stopping times (if the times are irregular).

I attempted at first to include this constraint while building the dataset using an attribute with a VBScript evaluator, but got stuck: I can't find any command in the expression builder that will query the solver for the elapsed time at a node (the current label) in the midst of the solve. 

Have I missed a way to set such a constraint up using the dataset wizard, or does the network solver function as a "black box" object with a tally that can't be queried mid-solve by any method contained in the dataset wizard or solver options? Is this a job for ArcObjects? I haven't yet located an object in the SDK help that can return the current state of the solver...Or is there a way to put this behavior together using one of the other solvers, such as the VRP, out of the box?  Expert help would be appreciated here.

Thanks,

Michael

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