Presentation on theme: "Tips, Trips, and Traps of TransCAD Modeling LSA Associates, Inc. September 2001 North Carolina MPO Conference."— Presentation transcript:
Tips, Trips, and Traps of TransCAD Modeling LSA Associates, Inc. September 2001 North Carolina MPO Conference
1 Why Model? Why Jurisdictions Convert to TransCAD? The Transportation Model GIS Developer’s Kit Applications Agenda
Why Model? Why do we model the transportation network?
3 Why Model? To consider the effects of land use, transportation, and air quality To determine infrastructure needs, costs, and timing as growth occurs To analyze land use and transportation alternatives To provide a consistent platform for travel forecasting Required by the federal government for metropolitan areas
4 The History of Travel Forecasting Aggregate Models Few zones Major highway planning only Computers available to large agencies 50’s 80’s 90’s 80’s and 90’s 00’s 60’s 70’s 60’s and 70’s Shift to microcomputers More zones Detailed transit and HOV models Computer chip technology advances Federal government sponsorship Travel behavior surveys widespread Basic transit capability Windows-based More disaggregation and detail GIS-based models Microsimulation
Why Jurisdictions Convert to TransCAD? Why are agencies converting their travel models to TransCAD?
6 Why Convert? Some widely-used older modeling software are no longer being supported – a new modeling platform is required Limited capabilities in Graphics Memory GIS Network size Number of TAZs
7 TransCAD Users There are many states in America that currently use TransCAD
8 Geographic Information Systems A GIS-based transportation model Compatible with other GIS tools Spatial Analysis ArcView Shape Files TransCAD *.dbd Files
9 Why TransCAD? A powerful modeling software that can enhance the modeling process Windows-based menus that are intuitive to manipulate A GIS software with transportation modeling capabilities No internal size limitations Scenario manager for easy file management Ability to easily analyze intermediate results Mapping and visualization tools designed for GIS and transportation applications TIP: Choose a powerful computer!
The Transportation Model What is involved with a travel demand model?
11 Modeling Process Trip Generation Trip Distribution Mode Analysis Traffic Assignment Socioeconomic Data Roadway Network Transit Network Transit Ridership Transit Assignment Roadway Volumes Performance Report How many trips? Where will they go? What mode? What route? Identify needs Alternatives analysis
12 TransCAD Inputs Easy to understand file structure No restrictions on file names, locations, etc. File names are easy to change in the model structure with the scenario manager, created in GISDK
13 TransCAD Outputs Checking intermediate modeling results is easy in TransCAD Identifying results from an individual project area allows detailed study of the project Performance module allows consistent reporting of results
14 Data and Databases Geographic data Network data Attribute data TransCAD model data Socioeconomic data US Census data Jurisdictional boundaries Zip codes Railroads Water Features Tiger Streets Files
17 Networks Networks are GIS databases Conflation to GIS distances and shapes Foundation for traffic counts, performance, transit, and any other data Multi-year network capability TIP: Keep raw count data and adjustments in traffic count database
18 Networks GIS Networks Roadway System Transit Routes Air Quality Performance Time of Day Volumes Project Selection (TIP/RTP) Traffic Counts
21 Traffic Analysis Zone Data Zonal areas used in modeling trips Ability to incorporate census data Used for summaries and reports Used for visually verifying data
22 Socioeconomic Data Interface with popular GIS platforms Land use to socioeconomic conversion using TransCAD’s GIS tools Visual representation of land use and socioeconomic data TAZ coverage provides foundation for area-based data and is easily modified TIP: Socioeconomic sub-model can use a Fratar process coded in GISDK
23 Socioeconomic Data and TAZ Structure GIS TAZ Structure Area Type 2020 Socioeconomic Data Performance and Air Quality Area based Indexes K Factors Terminal Penalties 1998 Socioeconomic Data
25 Trip Generation Robust cross classification production model Unlimited trip purposes Production allocation and attraction allocation models TIP: Include all modeling steps in TransCAD using GISDK, without compromising model structure. This ensures a full running model from start to finish.
26 Trip Generation Incorporate land use data Detailed trip purposes Distance-based allocation models Special generators Universities Hospitals Amusement parks Event centers Malls Government installations
28 Trip Distribution TIP: Geocode survey data in house to determine trip lengths Desire lines between TAZs and districts TRIP: GISDK standard gravity evaluation procedure does not correctly apply K factors in version 3.6 Friction factors – calibrated curves versus lookup table
29 Mode Analysis Customized nested logit and multinomial logit models TIP: Don’t be limited to standard TransCAD procedures, create exactly what you want with GISDK Distance-based bike and pedestrian equations
30 Nested Logit Structure Person Trips MotorizedNon-Motorized Drive AloneShared RideAuto PassengerTransit DA Non TollDA TollSR2 Non HOVSR2 HOVSR3 Non HOVSR3 HOVAuto ExpressAuto LocalWalk ExpressWalk Local Non HOV Non Toll HOV Non Toll Non HOV Toll HOV Toll Non HOV Non TollNon HOV Toll HOV Non TollHOV Toll ExpressUrban RailCommuter Rail ExpressUrban RailCommuter Rail
31 Traffic Assignment Time of day User defined volume-delay equations Speed post-processing Speed feedback AM peak – congested speeds Off peak – freeflow speeds All or nothing, capacity constrained assignments with comparison
32 TransCAD Transit Capabilities Walk access vs drive access Unlimited number of modes Unlimited number of variables Stops dependent upon individual routes
33 Transit Assignment Transit boardings by stop, by route, or by mode Drive or walk access assignment Transit flows by link Transit line volumes
34 Validation Screenlines – GIS line layer created quickly TRIP: One way links confuse the built-in screenline analysis functions
36 Model Conversion Process Existing Model Initial Model Conversion (Caliper or LSA) Network Conflation and Model Replication Model Enhancements Calibration / Validation TRIP: The base converted model is not ready to go! TIP: Develop performance reporting capabilities early. TRIP: TransCAD uses different distances – this may affect model results. TRIP: Need to adjust for software differences. Performance Reporting
GIS Developer’s Kit The endless possibilities with the TransCAD programming language
38 TransCAD Scripting Capability GISDK is the TransCAD programming language Allows for complete automation of the modeling process unique to each model Eliminates user error by programming all steps and variables in a model run Similar to programming in C++ (with different syntax and commands) Use the programming editor of your choice to create and edit the GISDK script TIP: Boxer Software is a good (and inexpensive) programming editor
39 Model User Interface The dialog boxes that run the whole model Reduce errors by eliminating point/click/type commands GISDK is the key to programming the model
40 TransCAD Dialog Boxes Custom user interfaces created using GISDK Fully automates the model procedures – including file names, variables, and summary reports TIP: These really help the consistency and accuracy of the model!
41 Scenario Manager Created using GISDK Manages all files related to each alternative
42 GIS Developer’s Kit (GISDK) Program exactly what we want TransCAD to do Allows for any mathematically sound method or procedure Not confined to standard TransCAD procedures Full dialog box customization
Performance Reporting The possibilities available for performance reporting
44 Provides consistent and convenient summary reports Created with GISDK Customized to the client’s needs Performance Module Analysis tool for troubleshooting model runs Facilitates calibration and validation TIP: Create EARLY in modeling process!
45 Summary Reports The summaries are customized using GISDK and summarize the model data in many ways, including… Facility Type and Area Type Capacity Analysis Congestion Delay Air Quality Emissions Results
Applications TransCAD applications for the transportation planning and analysis process
47 Land Use and TAZ Overlay Land Use Map TAZ Map Land Use and TAZ Overlay
48 I-25 Socioeconomic Data Analysis 1998 Data 2020 Data Land Use Data
49 I-25 Corridor Analysis 1998 Data 2020 Data Land Use Data
50 Supply and Demand Analysis Demand SupplyDifference
57 Travel Sheds / Critical Link Analysis Identify users of a specific facility Analysis for Adequate Community Facilities Ordinances and road fee programs
58 GIS-Based Transportation Improvement Programs AgencyProject Funding Amount AnaheimLincoln Avenue Signal Coordination $52,910 AnaheimState College Blvd @ SR-91 $150,000 Buena Park Artesia Blvd @ 1- 5 Interchange $132,795 Costa Mesa Fairview Road$29,846 IrvineBicycle Program$67,200
59 Transit Planning and Operations Strategic transit planning University transportation planning Corridor planning Market identification and productivity Management and placement of capital assets
60 Land Use / Transportation / Air Quality Conceptual level analysis of LUTRAQ relationship Comprehensive plan updates Triggers – population vs. VMT growth Air quality and emissions inventory Stationary and mobile sources On-road mobile emissions estimation Mobile5 Nonattainment area Energy and fuel consumption
61 Air Quality Analysis Link-based emissions Zone-based emissions (i.e. cold starts, evaporate VOCs, etc.) Air quality conformity determinations Redesignation and classification issues Integration with gridded urban airshed modeling Integration with Mobile5
62 Land Use / Transportation / Air Quality Available from the performance summary report for the Fort Collins Nonattainment area
63 Integrated Air Quality Modeling TransCAD Travel Demand Model (speeds, vehicle miles of travel, time of day, …) EPA Mobile/Part Emissions Models (temperatures, fuel characteristics, emission factors, …) Emissions from On-Road Vehicles
64 GIS-Based Emissions Inventories Link-based emissions Zone-based emissions Gridded Overlay for Region
65 Intersection Analysis Intersection Flow Diagram Volumes from TransCAD Traffic Counts NCHRP 255 Process VISSIM 3D Animation Synchro Intersection Analysis SimTraffic 2D Animation
77 Construction Management Modify signal timing in response to construction closures
78 Future TransCAD Applications Interactive MPO Project Prioritization and Funding Allocations Traffic Impact Studies: Cumulative improvements and impacts, time of day project distributions FHWA TDM Model Mixed Use Activity Center Trip Generation & Distribution Bicycle Assignments Transportation Corridors Pavement Management
LSA Associates, Inc. 132 West Mountain Avenue Fort Collins, CO 80524 970.494.1568 firstname.lastname@example.org
Tips, Trips, and Traps of TransCAD Modeling Presented by LSA Associates, Inc. September 2001 North Carolina MPO Conference Fayetteville, NC