Appendix B Land Use and Traffic Modeling Documentation
Technical Memorandum Planning Level Traffic for Northridge Sub-Area Study Office of Statewide Planning and Research Modeling & Forecasting Section May 24, 2011 Introduction This memorandum documents the model runs made in support of the request for planning level traffic received from CCSTCC and LJB consultants via email of 1/6/11. The planning study seeks to evaluate traffic conditions over a large area north of Springfield known as Northridge. In the discussions to follow, all folder references refer to: I:\ut\mpo\model\spr\proj\northridge\ For model runs, relevant files were copied to: I\ut\mpo\model\spr\oms\INPUTS\northridge Appendix A contains the study scope of services. A project kickoff meeting was held on 2/3/11 as documented in Appendix B. ODOT transmitted various information to the study team as contained in subfolder kickoff_mtg. At this meeting it was agreed that (see Appendix for details): 1. ODOT would update the travel demand model and provide LJB Synchro turn volume files for 2035 conditions. 2. LJB would provide a base year Synchro file to ODOT for use in updating the travel demand model networks. 3. Clark County and Springfield City would provide revised land use data to update CCSTCC data to 2035 conditions. These updates were received via email on 3/9/11 with clarifications through 3/15/11 and placed in subfolder LU_updates_from_locals. The AM and PM Synchro networks were also received on 3/15/11 and placed in subfolder Synchro. Model Updates and Refinements Network Updates To conduct this modeling, model networks were developed in the network subfolder. The following long range plan networks were copied over: Use Base Year EC Net Source LRP 2010 intermediate year network (INPUTS\lrp08\2010\spr10.net) (turn prohibitor INPUTS\LRP08\spr05pro.pen) LRP 2015 intermediate year network (INPUTS\lrp08\2015a\spr15a.net) (turn prohibitor INPUTS\LRP08\spr05pro.pen)
Build Net LRP 2030 network (INPUTS\lrp08\spr30a.net) (turn prohibitor INPUTS\LRP08\2018\spr18pro.pen) The 2010 network was checked versus the Synchro intersection coding and aerial imagery from OSIP, as well as on-line aerial imagery and edited (mainly attributes IXTYPE and TURNLANE) to produce the modified base year network spr10prj.net in the project s network folder. All the initial changes were saved in log files beginning with bryan (indicating the person who made the changes), these log files were then played on the future networks to produce the spr15prj.net and spr30prj.net files. The network was then heavily modified to support additional zones (see next section, 39 zones were added) and to add additional roadways. The additional changes needed for this as well as changes made during model calibration were saved in log files beginning with greg. Figure 1 compares the original base year network to the final network developed for this project. This network was also checked versus the actual roadways in the area for attributes LANES, FUNCLASS, AREATYPE, TURNLANE, IXTYPE, POSTSPD and various minor changes were made. While the model runs did not focus on transit the 2000 transit network was updated to maintain consistency with the highway network changes made to create a project network (spr00prj.lin). This can be edited in the future to update the system to 2010 conditions if future transit scenarios are to be tested. New traffic counts were coded in the study area as shown by the red road segments in Figure 2. These counts were obtained from the Synchro turn movement counts provided by LJB. While other counts were indicated on the RFP study area map, these were not provided to ODOT. AM total volume counts were placed in the model network COUNT2 field and PM counts in field COUNT4 (after clearing these fields). It should also be noted that in the checks that follow, the old year 2000 daily count (field AADT) from the model validation was occasionally used as well. Almost uniquely, during the model calibration checking, no speed modifications (SPEEDMOD) were necessary to make the model function within required tolerances.
Figure 1A: Original 2010 Network
Figure 1B: Revised 2010 Project Base Network
Figure 2 Hourly Count Locations (AM count shown closer to link, PM further)
Zonal Socio-Economic Data Updates This studies primary focus is to study the roadway system with future anticipated development impacts to year 2035. Therefore an extensive series of updates to the socio-economic data were made in the project s zonal_data folder. First, to ensure the TAZ system was compatible with the more extensive roadway network discussed previously and to better reflect the way the land uses in the area access the highway network, a number of traffic analysis zones were subdivided. Aerial photos overlaid with the zone boundaries and the network in GIS were used for this. The modeled development in each zone was also checked versus these aerial photos to ensure it was representative of actual conditions. The analysis began with the zone boundaries and zonal data created by CCSTS for the previous long range plan update which went to year 2030: Use Base Year Forecast Year Source LRP 2010 intermediate year SE data (INPUTS\lrp08\2010\ spr10zd.dbf) LRP 2030 SE data (INPUTS\lrp08\ spr30zd.dbf) Zones were subdivided in GIS as shown in Figure 3. In this figure the thick dashed blue lines are the original zone boundaries and the thin solid orange lines are the revised zone boundaries. A total of 39 zones were added in the project area. As can be seen in the figure, some of the added zones (see for example 332) do not currently contain significant development but were added to accommodate future development provided by the County and City. Once the zones were split, the highway network centroid connectors were updated to provide appropriate access for these zones to the network as shown in Figure 1. Next, the zonal data was split. To do this, GIS was used to overlay the old and new zone boundaries on Census blocks and QCEW employment data (see zones.map in Transcad to see the various GIS layers referenced). The Census overlay provided an estimate of how much population (and related variables) to allocate to each zone. Census blocks were subdivided in the project area where necessary to align with the new TAZ boundaries. In these cases aerial photographs were used and dwellings were manually counted to allocate population between split Census blocks. Tab POPULATION_DUMP in the spreadsheet was used to allocate population, households, group quarters and children directly while vehicles and workers were proportionally allocated based on population. For employment, tab EMPLOYMENT_DUMP shows the QCEW employment by subzone, since QCEW often contains various inconsistencies with the actual MPO employment data, these data are merely used as a guide in sub-allocating the employment which was done manually. Figure 4 shows a summary of these results for 2010 with the old zone in green (and with an o appended to the TAZ number) and subdivided zones below their parent zone. Besides subdividing zone, many updates were made. First, the City of Springfield and Clark County submitted updates (see Appendices C and D) for both 2010 and 2030. These updates were allocated to the proper zone using the map provided by the city and the zoning table provided by the county. The changes are shown in Figure 4 for 2010 and 5 for 2030, color coded orange for city updates and blue for county updates. For any demographic change made, an intermediate TAZ record with an a appended is shown with the amounts added due to the City/County update (versus the total in the final record).
Figure 3. Revised Traffic Analysis Zones During the course of the study, Census 2010 block level data became available. Therefore, the 2010 block data was mapped to the standard TAZ s in GIS (not the project TAZ s) and major growth areas were identified as shown in Figure 6. From this, population (and related demographic variables were added to the zonal data as shown by the purple shaded areas in Figures 4 and 5. The intermediate TAZ records with g appended show the amounts added to each zone. A number of additional updates were made to the zonal data based on analysis of the data versus aerial photos, Census and QCEW. These changes are shaded yellow and are referenced in the notes below the table in Figure 4. Once updated, the data was copied to a new sheet, the old and intermediate TAZ records were removed, it was resorted and saved out of the spreadsheet (via csv) to SPR10ZDPRJ.DBF and SPR35ZDPRJ.DBF. A linear interpolation to create SPR15ZDPRJ.DBF was made as well.
Figure 6 2000 to 2010 Population Change by Standard TAZ per US Census
Special Generator Updates In addition of updating the zonal SE data, the special generator file was updated as well. This file contains trip rate information for zones not adhering to the regional averages. Two sets of changes were made to this data starting with the areas standard special generator file copied from: INPUTS\Base\sprspecgen.csv to the project zonal_data folder. First, any zone that was split had to be checked versus this file to see if it was a special generator. Quite a few of them were mainly due to the proximity to the cordon which necessitated special generator records during the main models development to account for the larger amounts of external traffic here. These records were all evaluated and either allocated to a specific subzone or copied to all subzones of the original zone. The second change was made during calibration. It was determined that the commercial trips emanating from the retail area at Derr/Villa, the business on Moorefield and those on Eagle City Rd were somewhat under assigned so the shopping, non-home based and other trip attractions were doubled on zones 278, 284, 285, 338 and 342. In addition, the trip attractions for zone 318 were multiplied by 10 due to the large church there. The edited special generated was saved as: sprspecgenprj.csv. Changes in External Traffic Due to the proximity of his project to the cordon, the external station forecasts were checked, however, no changes were deemed necessary.
Setting Up and Checking the Model A new model scenario was created called northridge as shown in Figure 7. This scenario, based upon the 2010 network discussed previously, was used as the basis for model checking and refinement. Additional scenarios for the design year build/no build conditions were constructed as well (as discussed in subsequent sections). Figure 7 Model checks were conducted iteratively with the refinements mentioned previously and resulted in several of the adjustments discussed there. Four rounds of calibration and adjustment were made to the model as follows: Round 1 Use 2010 Census to update population levels Round 2 Split zone 37 further, adding zone 342, place NAICS 81 employment from z278 in this zone Revised posted speed limit on Urbana Rd after checking online street view Synthesized (made up) population/employment to represent facility seen in aerials in zone 320 Round 3 Move centroid connectors for zones 240, 323, remove centroid connector 216-439 Checked posted speed limit on Red Coach using on line street view and revised Multiply trip attractions on zones 278, 284, 285, 338 and 342 by 2, zone 318 by 10 Round 4 Change GPS_FACT from 0.0 to 1.0 Figure 8 shows the %RMSE curve in the project area for the AM and PM peak hours. While each curve shows a jump above the curve, they are minor. In general the curves are well below with the PM peak being better validated than the AM. The issue here appears to be in the AM peaking assumptions which apply to the whole County but appear to be slightly off for this particular area. Figure 9 compares the base year assigned AM volumes (closer to link) to the newly coded counts (further from link) while Figure 10 shows the same for PM volumes. Comparison is generally good though there are certain problem spots. The very high count on Hunt Pkwy is unexplainable; given the 2010 Census was checked to confirm the number of persons/households here. Also of note is the high AM peak count on Emmanuel Way while the PM values match well. A couple other problem spots include Vila approaching
Middle Urbana and Urban Rd north of SR 334. The results were deemed good enough, however, to proceed given that they will be adjusted with the NCHRP 255 process. Figure 8
Figure 9 Comparison of Model to Counts for AM Peak Hour (model closer to link)
Figure 10 Comparison of Model to Counts for PM Peak Hour (model closer to link)
Post-Model Adjustment Following adjustment/refinement of the model the results could generally be deemed planning level traffic though in many cases additional processing is necessary. For this study, since detailed turn movements were requested, this is the case and following the nomenclature of ODOT s project level forecasting guidelines, the traffic forecast produced for this study is more properly called refined alternative level traffic. Two methods have been used for this, the first is to use matrix estimation techniques to further refine the model results. This method has been used in areas with very complex traffic/signal system interactions, particularly in CBD areas and requires considerable overhead to set up and apply. The second method is to simply apply ODOT s standard NCHRP 255 based design traffic adjustment procedures at turn movement level. This is the method employed for this study. All turn movement counts from the Synchro model were entered into ODOT s standard spreadsheet along with the modeled turn movements. These spreadsheets are contained in folder: I:\ut\mpo\model\spr\proj\northridge\nchrp255 one for each intersection/forecast alternative. An example is shown in Appendix E. This process converts the model peak period volumes to hourly, then applies the ODOT modified NCHRP 255 adjustment process, then converts the volumes to design hour, then balances the resultant turn volumes to maintain consistency with input link flows. The resultant values were then compared with adjacent intersections to make sure there were no serious inconsistencies. In all but a couple cases the intersection flows were found to be consistent (accounting for intervening traffic generators). For SR 334/Middle Urbana intersection, one link flow over-ride was used to force consistency with adjacent intersections due to the absence of access points on SR 334. A constant design hour volume factor of 1.125 was used for all volumes in this study. Therefore, if subsequent analysis wishes to use average day volumes instead of design hour volumes, the numbers can simply be divided by this factor. Results Once the final turn volumes were calculated, they were output to Synchro format turn volume files which are contained in: I:\ut\mpo\model\spr\proj\northridge\nchrp255\CSV_FILES in four files: AMBUILD, AMNOBUILD, PMBUILD, PMNOBUILD. The raw model assignments are in: 2010 Base: I:\ut\mpo\model\spr\oms\Base\northridge\ SPR10J24ASNBASE.NET 2035 Build: I:\ut\mpo\model\spr\oms\Base\northridge\dy35\ SPR35J24ASNDY.NET 2035 Nobuild: I:\ut\mpo\model\spr\oms\Base\northridge\dy35\NB\ SPR35J24ASNDYNB.NET As well as the AM turning movement volumes in (substitute PM in filename for PM movements): 2010 Base: I:\ut\mpo\model\spr\oms\Base\northridge\ SPR10JTURNSAMBASE.DBF 2035 Build: I:\ut\mpo\model\spr\oms\Base\northridge\dy35\ SPR35JTURNSAMDY.DBF 2035 Nobuild: I:\ut\mpo\model\spr\oms\Base\northridge\dy35\NB\ SPR35JTURNSAMDYNB.DBF Figures 11-13 shown the daily model volumes for the base case, and forecast year no build and build respectively which gives an overview of how the volumes change by scenario (not all that much due to the low levels of background growth in the area and the modest new development provided). Figures 14-17 show the final hourly turn volume files for the forecast year as transmitted to LJB for further processing.
Figure 11 2010 Base 24 Hour Model TOTAL Volumes
Figure 12 2035 No Build 24 Hour Model TOTAL Volumes
Figure 13 2035 Build 24 Hour Model TOTAL Volumes
Figure 14 2035 AM No Build Turn Volumes
Figure 15 2035 PM No Build Turn Volumes
Figure 16 2035 AM Build Turn Volumes
Figure 17 2035 PM Build Turn Volumes
Appendix A Study Scope of Services
Appendix B Kickoff Meeting Minutes
Appendix C City Land Use Updates
Appendix D County Land Use Updates
Appendix E Sample ODOT Modified NCHRP 255 Adjustment Spreadsheet: SR 334 & Middle Urbana Rd, PM Peak, No Build DHV Factor, Turn Count and Leg Volume Over-ride Section
Optional Model Turn Volume Entry and 255 Adjustment
Turn Volume Balancer and Final Results (shown vs. original input counts)