Montgomery County Travel Forecasting Model Calibration

1
Montgomery County Travel Forecasting Model
Validation Status Report
Presented To TPB Travel Forecasting
Subcommittee By Montgomery County Department of
Park and Planning M-NCPPC March 18, 2005
2
(No Transcript)
3
Montgomery County Demographic Facts

Year 2000 HH Pop. Total Pop. Population
863,910 873,341 Adj. Emp.(a) Total
Emp. Employment 475,020 479,800 Note
(a) Applied MWCOG Employment Adjustment Factor
0.99
4
(No Transcript)
5
(No Transcript)
6
Montgomery Countys TRAVEL/2 Model

4-Step Model EMME/2 PM Peak only Validation
Year 1998
7
Why Adopt MWCOGs Model?

• Cost savings and more sharing of resources As
  the MPO of the region, MWCOG is federally funded
  and has the ability to devote more resources
  (staff and funds) in support of travel
  forecasting than Montgomery County.
• Consistency with the regional process Direct
  access to regional networks and data prepared for
  other jurisdictions in the region.
• More input to MWCOGs process More of an
  opportunity to develop and review inputs to the
  MWCOG process.

8
Why Adopt MWCOGs Model? (Continue)

• Credibility MWCOG goes through a very rigorous
  peer-review process and must meet federal
  requirement for travel modeling.
• Better integration with GIS TP has ability to
  read ArcGIS shape files. MWCOG has developed
  numerous tools databases to support data
  exchange between travel model and GIS.
• Tech Knowledge Sharing Base of local users,
  including MWCOG, BMC and several local
  jurisdictions would permit the sharing of
  techniques and knowledge.

9
Converting MWCOGs V2.1D Model 2000

• Zones
• 318 TAZ vs. MWCOGs 308 TAZ in Montgomery Co.
• Additional zones due to Takoma Park annexation
  in 1997 (Montgomery and Prince Georges county
  boundary change) more details around Metro
  stations
• Demographic Data
• Cooperative Forecasting Round 6.4A by 318 TAZ,
  with jurisdictional employment adjustment factor
  (0.99 for Montgomery County)

10
Converting MWCOGs V2.1D Model 2000 (Continue)

• Network
• Highway more links attributes in
  Montgomery County and some
  updates/corrections outside of the county
• Transit Modifications required to
  accommodate highway network changes

11
Montgomery County TAZ and Highway Network 2000 by
Facility Type

12
Model Validation Adjustments

• Adjustments
• (1) Trip Generation Adjustment Factors HBW
• (at Census Tract level)
• (2) Trip Distribution K-factors HBW
• (at Super District Level, 12 in Montgomery
  Co.)
• (3) Trip Generation Factors HBS, HBO, NHB
• (4) Highway Network Coding US29, etc.

13
(No Transcript)
14
Model Validation Data

• Data CTPP 2000 Screenline Counts

Census Adjustment Factors to convert workers to
trips (based on Metro Area Pop. 500K-1000K)
15
CTPP 2000 DataWorker to Trips Conversion

• Based on ltpublicationgt
• Determine modal composition of workers (CTPP)
• Determine metro area size
• Choose appropriate factors
• Absenteeism
• Mode Shift
• Multiple Trips
• Assume trip chaining factor 2.0 (daily model)
• Calculate composite conversion factors

16
Model Validation Tests

• Other Tests on Adjustments
• Trip Generation Factors HBW Ps
• Tried only adjust Productions using trip
  distribution table and decided to adjust both Ps
  and As using TG tables
• Trip Distribution K-factors HBS, HBO, NHB
• Tried and decided not to adjust non-work purposes

17
Model Validation Findings/Results

• Corrected general underestimation of commuter
  travel
• Within County
• To/from Prince Georges and Frederick
• From DC
• Non-work travel??

18
Model Validation Findings/Results

• Changes in trip purpose mix (graphics to follow)

19
Model Validation Findings/ResultsCommuters

Comparison of CTPP 2000 and Estimated
Travel Montgomery County
20
Model Validation Measure - TLF

• Commuter Trip Length Frequency - shorter

21

22
Next Steps

• Mode Choice Model Validation
• Traffic Assignment Validation
• Comparison with TRAVEL/2 PM Peak Model

23
Challenges/Lessons Learned

• Data, Data, Data!
• Network, Network, Network!

24
Acknowledgements

• MWCOG
• data files, discussion, technical support
• Consultant Michael Baker Jr. ,Inc.
• technical guidance, data, model validation
• M-NCPPC Prince Georges County Staff
• sharing ideas and data, comments
• M-NCPPC Montgomery County Modeling Staff
• Yetta McDaniel and Ronald Vaughn
  (Network/GIS/Counts)

25
Questions?
?