BMC Modeling Peer Review Panel Meeting
12/6/2013
Panel topics of interest
Survey currency
Planned 2014 ridership survey. Make sure it has relevant questions for ABM validation. E.g. retrieve tour details. Documentation from Cleveland and Columbus. FTA Luvs It.
Geographic disaggregation
Smaller zones, point-based activities, micro-analysis zones for better modeling of transit access/egress.
Temporal disaggregation
Is 30 minutes too coarse? How about 15 minutes? How about a continuous time model? This will help pave the way for a DTA.
Validation
Constraints of data availability on disaggregate validation. E.g. time-of-day. Speed data.
Peak spreading
Suggest including explicit flexibility of work schedules as a person attribute to permit policy analysis.
Audience concerns
Adequacy of survey data
2007 is not too old. Newer data will be useful for validating model sensitivity to background influences. Consider establishing a continuous survey program.
Precision of assignment results
ABM does not, by itself, guarantee better assignment results due to inherent limitations of static assignment and network accuracy. Effects of this project on goals of climate change will be limited to travel choice and constraints. Addition of assignment time periods will assist in troubleshooting and re-calibrating network assignments. Many more solutions to assignment precision are available in DTA.
Validation topics
Need to obtain diurnal traffic counts. There are many more dimensions for validation in ABM. Some can be internally validated against the survey. Validation on transit per FTA guidance (e.g. district to district linked flows).
Land use effects
Does the entire model sequence adequately reflect the interest in understanding the causal relationships between built environment, accessibility and travel choice. (i.e. beyond mode choice).
Specific requests
Tolling and managed lanes
Mode choice components should be tied to high-level behavioral preferences (value-of-time segmentation) and network components should be based on performance. Segmentation by value of time is a good idea. It is o.k. to do logit route-type choice, or alternately binary choice, within each segment. If the number of VOT segments mimics a continuous distribution, then binary choice will not be needed; if less, then still test binary choice.
Zone density in MWCOG
Use a consistent geographic micro-zone scale (e.g. parcels) across the entire BMC modeling region. Use empirical data to the extent possible and use disaggregation algorithms when not.
Definition of modes in mode choice
Emphasize unique service variables in network coding (e.g. station type), elaborate path building choice logic, and keep the mode choice model shallow. Binary, or Conventional vs. Premium, distinguish between walk, P&R and K&R access/egress. Multi-class transit assignment by user class (income group and age).
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