PC Software for Urban Transportation Planning

PC Software for Urban Transportation Planning American Planning Association. Journal of the American Planning Association; Spring 1992; 58, 2; ABI/INFORM Global pg. 238

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PC Software for Urban Transportation Planning Erik Ferguson, Catherine Ross, and Michael Meyer This article reviews nine PC-based urban transportation planning (UTP) software packages, all of which are relatively complex and require significant education, training, and experience to use properly. Inappropriate use of UTP modeling software can result from insufficient training or data, improper model calibration, inappropriate model application, or from the black box syndrome, which often plagues complex modeling efforts. Recent UTP modeling innovations include new developments in the areas of subarea focusing, site impact analysis, the evaluation of travel demand management strategies, the integration of UTP models with geographic information systems, and the integration of land use and activity modeling with the traditional fourstep UTP process.

The long-range, regional travel demand forecasting tools that professionals use in urban transportation planning (UTP) are traditionally based on a four-step process, which describes travel behavior decision making at the individual level in a highly simplified yet reasonably flexible manner. This process typically forecasts future travel demand by employing separate forecasting submodels for trip generation, trip distribution, modal split, and route assignment, usually on a regional basis. The process describes the transportation system in terms of a simplified network of links and nodes. The models employ projected land use patterns, generally defined in terms of the dis· tribution of population and employment by traffic analysis zone, to forecast future transportation demands. Until quite recently, forecasters used only mainframe computers for these applications because of the relative complexity of these models. Today, most UTP professionals use personal computers (PCs) that are as powerful as the mainframe computers of the past and offer a number of distinct advantages. Their lower cost, smaller size, and increased ease of use make them highly suitable for UTP modeling (Skabardonis 1985). More organizations now have access to these tools, which has contributed somewhat to the development of new analytical capabilities and types of analyses (Roden 1988; Shea and Fleet 1986). Nevertheless, there are many unresolved issues in using microcomputers in place of mainframes for UTP modeling. The interface between the two is not yet well developed, even though many microcomputer-based UTP programs are adapted directly from older mainframe programs. Security may also be a problem because of the greater accessibility that microcomputers afford to a wide range of users. Portability from one operating environment to another can be a problem for some users (Bower and Abkowitz 1985).

PC-Based UTP Software Although other commercial PC-based products are available, the nine UTP software programs reviewed here make up the bulk of this highly specialized product line. All of the programs run on IBM personal computers and compatible systems.

Ferguson is assistant professor in the graduate city planning program in the College of Architecture at Georgia Institute of Technology. Ross is a senior research adviser at the Transportation Research Board in Washington, D.C. Meyer is a professor in the School of Civil Engineering and director of the Transportation and Research Education Center at Georgia Institute of Technology. Journal of the American Planning Association, Vol. 58, No. 2, Spring 1992. © American Planning Association, Chicago,IL.

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• The Highway Emulator (THE): THE is by far the most basic of the programs, providing neither graphics nor training and very little technical support. The program requires relatively little training, however, because of its simplicity. The program is available for free from the developer. Its primary use is for site impact analysis, most often as applied to developments of regional significance in smaller urban areas or in the outlying suburbs of larger cities. This package is one of the few that can be used to develop synthetic origin-destination trip tables, based on existing traffic counts. This approach works best when origin-destination data are

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lacking and vehicle counts are available for all or most of the key route segments in the study area (a common enough occurrence). Quick Response System (QRS) II: QRS II is based on the National Cooperative Highway Research Program Report 187. which outlines the quick response system developed by the Federal Highway Administration for sketch planning and site impact analysis in small urban and rural areas. While QRS II has been greatly expanded since its introduction. it is still mainly a tool for smaller UTP applications. Because QRS II includes defaults for all model settings based on accepted industry standards. it is perhaps the easiest package to learn and use. TRIPS: TRIPS is a British product. more widely used in Europe than in the United States. TRIPS's primary distinction is its fairly robust dynamic route assignment algorithm. which explicitly considers intertemporal changes in traffic congestion at specific intersections. This make TRIPS particularly useful for modeling highly congested or saturated flow networks. TRIPS also includes many additional features. which are available at additional cost. TransCAD: TransCAD was the first PC-based UTP software program to combine a true geographic information system (GIS) with a fully integrated UTP model. TransCAD was also the first UTP program to offer a fully integrated set of menu screens. The network building facility in TransCAD can be quite challenging to master. even for experts. MINUTP: MINUTP is based on a variety of UTP utilities developed over the years by the COMSIS Corporation in response to client needs. For example. COMSIS recently developed an elasticity-based TDM (travel demand management) evaluation utility for use in conjunction with MINUTP. TMODEL 2: TMODEL 2 is one of the older PC-based UTP programs. The program treats networks for different modes separately. assigning mode split prior to trip distribution. The program calculates intersection delays with internal variable formulae. rather than having the delay definitions fixed as constants internally by the modeler. TRANPLAN: TRANPLAN is one of the most commonly used PC-based UTP software programs in the U.S. TRANPLAN may not be the fanciest program. in terms of offering multiple versions of advanced route assignment procedures. but it does provide all of the options normally associated with the traditional fourstep UTP process. TRANPLAN is often favored for areas in which trip estimation and assignment have legal implications or when state planning agencies require standardized model outputs. SYSTEM II: JHK and Associates developed the commercial version of SYSTEM II quite recently. This is the newest UTP model on the market. although JHK based it largely on utilities it has developed over many years. SYSTEM II includes some elements of a GIS. as well as a variety of fairly new features designed speAPA JOURNAL

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cifically to accommodate its use for subarea focusing and site impact analysis. • EMMEj2: EMMEj2 is a Canadian product that is in many respects the Cadillac of UTP software. The price leaves little doubt about this. EMMEj2 provides the best documentation of any UTP package. way beyond the usual perfunctory references to the literature. EMMEj2 does not include default settings for any procedure. reflecting a philosophy that the user should be able to specify an appropriate model form. understand what the model represents. and be aware of its potential limitations. EMMEj2. not designed for beginners. is appreciated by more advanced UTP modelers.

Consumer Considerations Factors to consider before buying PC-based UTP modeling software include cost. size. special features. model components. equipment requirements. and documentation (see Table 1).

Cost PC-based UTP models are almost always expensive. The direct cost of a single-site. single-machine UTP software license agreement varies from as little as fifty dollars to thousands of dollars or more. The major cost associated with UTP models. however. is generally not the direct licensing cost. but rather the associated expenses of labor. set-up. and peripheral equipment. All of the models require extensive education. training. and experience for proper application. Most commercial vendors provide on-going technical support. individual tutoring and group training. and professional development workshops. These are all highly recommended because none of the programs is designed for off-the-shelf amateur use.

Size These programs are generally adequate for most UTP applications. THE and QRS II. however. are fairly restricted in the size of the networks they can handle. Many of the other programs discussed here are available in different configurations for analyzing networks of different sizes; the capacity depends on the price.

User Interface Until recently. UTP software offered little in terms of graphics support or menu-based command screens. This has changed dramatically in the last few years. All of the programs offer significant graphics capabilities. with the exception of THE. All offer some form of menu screen interface. with four of the nine now fully menu-driven. Reports may be customized. though often with some difficulty. Most of the programs provide formats for importing and exporting data to a number of standard formats and other UTP software programs.

Model Components All of the programs offer network building facilities. Most are limited. however. in terms of the number of

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ERIK FERGUSON, CATHERINE ROSS, AND MICHAEL MEYER TABLE 1: PC-based UTPM software features Feature

THE

QRSII

TRIPS

MINUTP

TransCAD

TMODEL2

TRANPLAN

SYSTEM II

EMME/2

Minimum cost Commercial license" Educational license" Training/workshopsb Technical support C

$50 $50 None None

$195+ $50 $200 $72/hr

$2,200+ $220+ Available $330+

$2,995+ $695 $1,000 $450+

$3,000+ $500 $500 $500

$3,800 $150 $210 $342+

$3,800+ $600+ $250+ $456+

$6,000 $200 $80/hr $1,000

$9,000+ $300 $300 $1,080+

3,000 2,000 300

4,800+ 3,200+ 585

Unlimited" 9,999 2,000

200,000+ 100,000+ Unlimited"

32,760 16,380 2,000+

10,000+ 2,500+ 1,000+

32,000 16,000 3,000

32,767 32,767 2,000

32,000+ 10,000+ 1,600+

None Some A

Yes Some A

Yes Some A

Yes All A. U,

Yes Some A,U

Yes All A,U,O

Yes All A,U

Yes All A,U,O

Yes Some A

H C G None 1,0

H, T R,C,O G,O L A, S, 1,0

H, T R,C,O G,F D,L A,S,I,O

H, T R,C,O G, F, a D,L A,S,I,O

H, T,O R,C,O G,F

H,T,O" R,C G, F, a D A,I,O

H, T,O R,O G,F,O" D, L, a A,S,I,O

H, T,O R,C G,F D, L, a A, S, 1,0

H,T,O C,O G, F, a D, L, a A,I,O

0286 612K 1MB None None None

0286/0386 512K 512K CGA/VGA Optional Windows"

0286/0486 640K+ 40MB EGA/VGA Required Sort utility

0386/0486 640K/2MB 40MB/100MB VGA/SVGA Recommended None

0286 640K 1.5MB/6.5MB EGAjVGA Optional Plotter

0286/0486 256K/640K+ 20MB CGAjVGA Optional Plotter

0286/0486 640K/4MB 6MB+ EGAjVGA Required Text editor

0286/0386 640K/2MB 40MB/100MB EGAjVGA Required RAM drive

0386 2MB 60MB VGA/SVGA Optional None

Maximum sized

Links Nodes Zones User interface Graphics Menu screens Import/export'

a

Model components Networks g Trip generation' Trip distribution i Mode split" Route assignment'

a A, S, I,

a

PC equipment m CPU RAM Disk storage Graphics monitor Mouse Other

a. Minimum purchase price for an individual site license agreement. Licensing conditions may vary. Multisite, multiuser licenses generally cost more. b. Per day, exclusive of travel costs. c. Per year. Normally offered in conjunction with a maintenance contract that includes free upgrades when the software program is substantially revised. d. For the highest cost model. e. Limited only by available memory and/or table size for different procedures. f. A ~ ASCII, U ~ UTPS, a ~ Other. g. H ~ Highway, T ~ Transit, a ~ Other. h. In preparation for release. i. R ~ Regression, C ~ Cross-classification, 0 ~ Other. j. G ~ Gravity, F ~ Fratar, 0 ~ Other. k. D ~ Diversion, L ~ Logit, 0 ~ Other. I. A ~ All-or-nothing, S ~ Stochastic/probabilistic, I ~ Incremental/dynamic, 0 ~ Other. m. Required/recommended.

links and nodes, the types of networks, and the connections they provide between networks serving different travel modes. Most of the programs adequately handle trip generation and trip distribution. Several treat modal split cursorily; THE is suitable only for highway analysis. Most of the programs focus on highly detailed, very accurate route assignment as the primary-if not the onlyanalytical objective. This emphasis makes sense for modeling travel behavior in a world dominated by private automobiles experiencing large and growing levels of traffic congestion.

is generally an 80286 CPU, with 640K RAM, a math coprocessor, a 10MB hard disk, and an EGA graphics monitor. For most applications, however, bigger and faster is definitely much, much better. Highly recommended are an 80486 CPU, at least 4MB of RAM, a 40MB or larger hard disk, enhanced VGA graphics, and a mouse for interactive network building on screen. Several vendors are experimenting with Windows versions of their software. Using UTP software in a Windows environment will facilitate the transfer of data to and from other programs but may degrade computational speeds slightly.

PC Equipment Hardware requirements vary widely, mainly as a function of the maximum network size and the graphics interface provided. The minimum required configuration APA JOURNAL

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Documentation UTP models are complex. If they provided full commercial product documentation, the manuals might be-

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PC SOFTWARE FOR URBAN TRANSPORTATION PLANNING come so long that general reader accessibility would still be difficult, if not impossible. This underscores the need for adequate modeler preparation, prior to the development of any full-scale UTP application. Fortunately, there are two national centers that assist in selecting UTP software and providing technical aid: the McTRANS Center at the University of Florida and the Transportation Center at the University of Kansas.

Inappropriate Model Application Forecasters sometimes use UTP models at inappropriate scales of analysis, either too large or too small. None of these packages is well suited for site impact analysis at a very small scale, e.g., for a single intersection. The first two packages are inappropriate for detailed regional modeling in small urban areas, or even for sketch planning at the regional level in larger urban areas.

The Black Box Syndrome

Modeling Problems Cook, Lewis, and Minc (1989) suggest that the main problems in using existing UTP models are practical, not theoretical. While this may overstate the case for most UTP models, it is an important consideration in evaluating the effectiveness of PC-based UTP models. Practical problems abound.

Insufficient Training Researchers often complain that practitioners are unreceptive to new ideas and improved models for travel demand forecasting. Commercial model developers claim to be market driven, yet ignore much of the research that has been conducted over the past twenty years. Educators continue to provide only the most basic instruction to students in the use of UTP modeling programs. Most agencies and firms require little or no prior education and experience with the UTP system, the UTP process, or particular programs as a condition of employment. To address these issues, it is important that improved professional standards be established for using UTP modeling programs, based on adequate levels of training, education, and experience. Many UTP model users do not understand the UTP process, or its inherent limitations. As a result, the range of professional expertise in handling UTP models is uncomfortably wide.

Inadequate Data There is a general lack of adequately detailed, current, or even relevant data for UTP modeling. Detailed regional data on travel behavior, needed as UTP model input, are nearly twenty years old for most large urban areas in the U.S. The exception is work-trip data, which continues to be collected as part of the decennial population census in large urban areas. Unfortunately, work trips have been declining in significance for over twenty years, and currently constitute only 20 percent of all urban trips. The effect of using old or irrelevant data is unknown, but presumably detracts from overall UTP model accuracy.

Improper Model Calibration Quite often, insufficient effort is made to calibrate UTP models accurately. This is probably because few if any professional standards are available for determining whether a particular model calibration is adequate for planning purposes. Professional judgment is the most common evaluation standard and retrospective analyses are rarely if ever conducted. APA JOURNAL

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Closed model structures may hide general data problems or specific programming errors. However, opening up model structures for complex software programs such as these is hardly the solution to the black box syndrome that continues to plague UTP modeling efforts. In this regard, the new easy-to-use, menu-driven, interactive interfaces, increasingly popular in PC-based UTP programs, may prove to be a mixed blessing if increased user-friendliness contributes to the continued misuse of these complex modeling procedures.

Recent Innovations Recent innovations in PC-based UTP modeling software programs include (1) new or substantially revised capabilities for subarea focusing and site impact analysis; (2) the evaluation of travel demand management (TDM) strategies; (3) the integration of UTP models with GIS; (4) simultaneous transportation-land use interaction modeling; and (5) the introduction of user-friendly, menudriven, fully integrated, graphics interfaces. Microcomputers are excellent tools for site impact analyses, which focus on a limited geographic scale and must often be completed quickly. Spreadsheet models such as the SITE model (Institute for Transportation Research and Education 1987) allow the analyst to input land use data directly. THE, QRS, and SYSTEM II are specifically designed for use at smaller scales of analysis. Large-scale regional travel demand forecasting models can also be used for site impact analysis by dividing large analysis zones into smaller ones, and adding more network links in the immediate vicinity of the study site. A comparison of several PC-based UTP software programs found that identifying the boundaries of the study area had a greater influence on overall model results than the particular modeling program (Swindler 1991). Model results were more reliable at the center of the study area than near the boundaries. It is therefore crucial to locate the study site in the center of the modeling area to reduce these boundary effects. In general, PC-based UTP software packages become increasingly unsuitable as the size of the proposed development decreases. TDM normally attempts to reduce the number of vehicle trips to or from a site at a particular time of day (e.g., rush hour). This is usually achieved by increasing average vehicle occupancy or by spreading vehicle trips around the target time period (Ferguson 1990). The increasing popularity of TDM has created a need for estimating vehicle trip reductions associated with the im-

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ERIK FERGUSON, CATHERINE ROSS, AND MICHAEL MEYER plementation of different TOM programs, projects, or policies. One approach has been to link software packages that use relative time and cost elasticities to estimate changes in travel demand with more traditional PC-based UTP packages. TOM evaluation capabilities may also be incorporated directly into future UTP models. Relatively few combined GIS-transportation (GIS-n models currently exist. However, many state transportation departments are developing GIS-T models, either in-house or in collaboration with GIS vendors (Vonderohe, Travis, and Smith 1991). The use of GIS-T models, when combined with digitized spatial databases like the Census Bureau's TIGER system, will provide additional modeling capabilities for site impact analyses. GIS will also make it much easier to subdivide traffic analysis zones and to integrate small- and large-scale activity and travel demand models into simultaneous transportationland use interaction models (Ferguson and Drummond 1989; Patterson and Ferguson 1990). The Japanese (Aoyama 1989) and Europeans (Webster, Bly, and Paulley 1988) seem to be making more progress in developing integrated transportation-land use interaction models than the United States. These models may be of greatest use in developing countries experiencing rapid urbanization where financial resources are in short supply and massive transportation and public utility investments may lead urban expansion along inappropriate paths (de la Barra 1989). Even in the U.S., integrated models may be needed to portray accurately transportation and land use equilibria (Berechman and Gordon 1986). UTP models used to be slow and cumbersome, producing results that were often quite inscrutable. On balance, this was probably beneficial for maintaining the accuracy and precision of model results, given the limited availability of appropriate data and the simplicity of the methods within these models. Today, slick packaging and easy-to-use menu screens and graphics icons are making UTP models more accessible to an ever-widening audience. Ensuring that these changes improve model performance and provide better information for planning and policy analysis requires equally significant improvements in the underlying data and UTP modeling procedures. Without these, the quality of UTP modeling results will almost inevitably decline, in direct opposition to our hopes and dreams.

AUTHORS' NOTE The authors would like to thank Kevin Olinger, Rod Swindler, and the software vendors for their assistance in preparing this review. The authors are responsible for any errors that remain.

THE UTP SOFTWARE REVIEWED EMME/2; Mail Orders: Barton-Aschman Associates, Inc., 100 Park Center Plaza, Suite 450, San Jose, CA 95113.

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Telephone Inquiries: William B. Davidson, 408-2806600, 408-280-7533 FAX. MinUTP. Mail Orders: COMSIS Corp., 8737 Colesville Rd., Suite 1100, Silver Spring, MD 20910. Telephone Inquiries: Victor Siaurusaitis, 301-588-0800, 301-5885922 FAX. QRS II (Quick Response System 11); Mail Orders: AJH Associates, 4845 N. Newhall, Milwaukee, WI 53217. Telephone Inquiries: Shirley Horowitz, 414-963-8686, 414-964-4417 FAX. SYSTEM II; Mail Orders: JHK and Associates, 4660 Kenmore Ave., Suite 1100, Alexandria, VA 22309. Telephone Inquiries: David Roden, 703-370-2411. THE (The Highway Emulator); Mail Orders: Central Transportation Planning Staff, 10 Park Plaza, Room 2150, Boston, MA 02116. Telephone Inquiries: Daniel Beagan, 617-973-7090, 617-973-8855 FAX. TMODEL 2; Mail Orders: Tmodel Corp., 17520 Vashon Hwy, SW, Suite 221, P.O. Box 1850, Vashon, WA 98070. Telephone Inquiries: Robert Shull, 206-4633768,206-463-5055 FAX. TRANPLAN; Mail Orders: The Urban Analysis Group, 375 Diablo Rd., Suite 110, Danville, CA 94526-3430. Telephone Inquiries: Jim Fennessy, 510-838-1363, 510-838-1372 FAX. TransCAD; Mail Orders: Caliper Corp., 1172 Beacon St., Newton, MA 02161. Telephone Inquiries: Howard Slavin, 617-527-4700, 617-527-5113 FAX. TRIPS; Mail Orders: MV A Systematica, MV A House, Victoria Way, Woking, Surrey, ENGLAND, GU21 1DO. Telephone Inquiries: Martin Bach, 44-483728051,44-483-755207 FAX.

REFERENCES Aoyama, Yoshitaka. 1989. A Historical Review of Transport and Land-Use Models in Japan. Transpor· tation Research 23A, 1: 53-61. Berechman, J., and Peter Gordon. 1986. Linked Models of Land Use-Transportation Interactions: A Review. In Advances in Urban Systems Modelling, edited by B. Hutchinson and M. Batty. Amsterdam: North HoIland. Bower, Dan, and Mark Abkowitz. 1985. Security Issues for Microcomputers. In Microcomputer Applications Within the Urban Transportation Environment, edited by Mark D. Abkowitz. New York: American Society of Civil Engineers. Cook, Peter, Simon Lewis, and Marcelo Minc. 1989. Comprehensive Transportation Models: Current Developments and Future Trends. ITE Journal 59, 6: 33-8. de la Barra, Tomas. 1989. Integrated Land Use and Transport Modeling: Decision Chains and Hierarchies. Cambridge: Cambridge University Press. Ferguson, Erik. 1990. Transportation Demand Management: Planning, Development, and Implementation.

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PC SOFTWARE FOR URBAN TRANSPORT ATION PLANNING Journal of the American Planning Association 56, 4: 442-56. Ferguson, Erik, and William J. Drummond. 1989. Disaggregate Discrete Choice Behavioral Modeling and GIS: A Transportation Perspective. Proceedings of the 27th Annual Conference of the Urban and Regional Information Systems Association 1: 1-12. Institute for Transportation Research and Education. 1987. SITE Impact Evaluation: Methodology and Microcomputer Methods. Report No. FHWA-HI-88-046. Washington, DC: U.S. Department of Transportation. Patterson, Paul, and Erik Ferguson. 1990. A Dynamic Disaggregate Model of Location and Travel Behavior Using GIS. Proceedings of the 28th Annual Conference of the Urban and Regional Information Systems Association 1: 186-98_ Roden, David B. 1988. The Development of a Regional Information System and Subarea Analysis Process. ITE Journal 58, 12: 270-31. Shea, Carl G., and Christopher R. Fleet. 1986. Down-

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loading Data for Trip Generation Analysis Using Lotus 1-2-3. ITE Journal 56,3: 42-7. Skabardonis, Alexander. 1985. Use of Microcomputers in Transportation: Potential Limitations and Future Trends. In Microcomputer Applications Within the Urban Transportation Environment, edited by Mark D. Abkowitz_ New York: American Society of Civil Engineers. Swindler, Rod. 1991. Comparison of transportation planning software as applied to site impact analysis. Master's thesis, School of Civil Engineering, Georgia Institute of Technology, Atlanta. Vonderohe, Alan, Larry Travis, and Robert Smith. 1991. Implementation of Geographic Information Systems (GIS) in State DOTs. NCHRP Research Results Digest 180: 1-32. Webster, F. V., P. H. Biy, and N. J. Paulley, eds. 1988. Urban Land-Use and Transport Interaction: Policies and Models. Brookfield, VT: Gower.

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