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ACRE H-l ~ Final Report EXECUTIVE SUMMARY ES.} Objectives This Is the final project report for TCRP Project H-12, Irz~egrated Urban Models for Simulation of Transit and Land-Use Policies. The stated objectives of this project are to: . . . Define more clearly the impact of transit access on land-use ,, Evaluate the access component of existing Arouse models; and Augment ongoing work by the Travel Mode! Improvement Program (TMIP), and others, to incorporate transit access into land-use models. Ultimately, the project defines a framework for enhancing integrated transportation - [and-use models. The focus is on the representation of land-use - transit interactions, so that these models cart provide useful, credible and timely inputs into the transportation / transit planning process. The framework defines long-term research and development needs, as wet! as actions that improve the applications of existing models In the short-term, and that provide He ';bndge" to move forward both practice and research in the medium-term. Key Definitions Travel demandforecasting models are used to predict have] pattems on a transportation network. The models simulate Raveler behavior as a function of human activities -- generally measured in terms of land-use (see below3 ~ d the charactenstics of the network (i.e., "accessibility" which is a function of travel costs, service levels, etch. Land-use models forecast demographic and economic measures of land-based activities. These measures describe the population (e.g., age-group cohorts, income. jobs, etc.) as well as built space (e.g., dwelling units' commercial floor space, etc.~. Integrated Transportation - land-use models simulate the interaction of land-use and transportation. They provide a feedback mechanism between the two types of models. The feedback recognizes that land-uses (more specifically, human activities and choices) influence travel behavior and the shape of the transportation network. which ultimately influences the | distribution and magnitude of different land-uses and, it follows, urban form. l - 1 -
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TORT H-19 Final Report Accompanying this report are Guidelines for implementation and Use of integrated models. The Guidelines describe how MPOs. State DOTs and other planning agencies can act todays in order to initiate or build upon existing integrated transportation - land-use models. ES.2 Why Integrated Models? Accompanying this report are GuidleZines for Implementation anct Use of integrated models. The Guidelines descnbe how- MPOs, State DOTs arid other planrung agencies can act today, in order to initiate or build upon existing integrated transportation - land-use models. The curTent interest in integrated models is motivated by three main factors: . . . Recognition that while transportation and land-use are strongly related, the current means of analyzing this relationship are limited. This was found to be true particularly with the transit - land-use interaction. Legislative requirements to achieve air quality standards, which require a proper understanding (and, therefore representation) of both the land-use - transportation air quality chain and the role that transit can play as an alternative to the auto; as evidenced by TEA-21 (and its predecessor, IS TEA) and the 1990 CAAA. ISTEA specifically required transportation pearls to be coordinated and consistent with land- use plans. TEA-2 ~ maintains this linkage, albeit in somewhat broader terms. Fundamental restructuring of the process of travel demand forecasting, as evidenced though TMIP. Through Track E of its six-part program, TMTP recognizes that an updated treatment ofthe land-use - transportation interaction is essential in Beirut able to simulate both travel demand and, ultimately, vehicle emissions. ES.3 The Transit- Land-Use Interaction An extensive literature documents our current empirical understanding of the relationship between land-use and transit. As part of TCRP Project H-12, a review of this literature was conducted. The results are summanzed below-. Mom two perspectives: first, the implications of land- use (defined as urban forms on travel; then. the implications of travel on urban form. Implications of urban form or' transit use. The findings are diverse. However, seven factors were found to influence travel activity, as listed below: Residential density Transit supply Auto ownership Socio-economic factors (e.g. income , age, gender, occupation, etc.)
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TCRP H-12 Final Report Employment density Accessibility (i.e. how- well connected a Oven location is wad human activities such as work sites etc.) Neighborhood design Figure ES. ~ conceptually links these seven urban form factors with Ravel activity. , · .. . . . (The figure also recognizes the explicit role of transportation supply in Gavel activity -- i.e., the definition of the road and transit systems). In this figure, activity / travel behavior is shown to be the ;'outcome' of a complex set of interactions among Me various factors discussed above. Figure ES. ~ illustrates two key points: ';Urbar~ form. or ';land-use" or "physical design" (as represented by residential density, employment density and neighborhood design) provides a context for human behavior, which, in this case, includes location decisions (residence, job locations). auto ownership decisions, and, ultimately, activity/uavel decisions. Increased residential density does not directly "cause" reductions In auto VMT. Rather, under the right circumstances, it may attract a resident population with particular socio- econom~c charactenstics and desired activity patterns who wait make auto ownership and travel decisions that we result in increased trar~sit/walk usage, reduced VMT, etc., relative to what they might do in other urban form contexts. Numerous supply-demand or feedback Interactions exist within this system. Travel decisions affect road congestion levels, which, in tum, affect travel decisions residential densities combined with attributes of the resident population affect the level of transit service provided, which, in turn, affects the attractiveness of the residential area for people of different types, etc. Ignoring these complex interactions and analyzing the system in a partial, overly simplified way almost inevitably leads to misleading or even erroneous results. Implications of transit on urban' form. The findings again are diverse. Observations may be made: Fixed, permanent transit systems have the greatest impact Transit's impacts are measurable ordy In the long-term. However, four main It is transit s impacts on land / development markets -- not land values -- that must be considered. Transportation is a facilitator of development -- not a cause. . . . I,]
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TCRP N-12 Final Report Figure ES.! Urban Form Impacts on Activity and Travel ( Anto ~ fA~ /! By' _- .. ~ no, - .~ _(Accessibility) - - 1V / _ ((mploymen) 'l~ Density ~ ==~g I TR AVFJII I
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TCRP H-12 Final Report ES.4 Present and Future of Integrated Models TCRP Project H-12 defined the framework for enhancing integrated models in terms of art 'ideal. model. It addressed three issues, as outlined in the following sub-sections: ES.4.l What Should Integrated Models Be Able To Do? Integrated urban models should be: · Theoretically sound, based upon the determinants of the "transportation - lan]-use7' connection. Result-driven, but respectful of due process and over practicalities (such as the input data that are, or are likely to be, available). Responsive to the issues faced currently by MPOs, transit operators anc! others involved in urban transportation planning, including finances, legislative requirements, local zoning, public accountability, the role of the private sector, etc. Cognizant of the regional, state, national and giobaZ demographic and economic inter-relationships that guide the pace of urbar1 development. Practical to operate, with me~ngfu! outputs and a traceable, defensible process. · Su~icientlyflexible to accorrunodate Me Mitering scales and magnitudes of different cities and regions. Presentable in art derstandable way to decision-makers arid the public. ES.4.2 The 'ideal' Integrated Model: Concept Figure ES.2 is a highly idealized representation of a comprehensive transportation - land-use modeling system. At its core (the shaded area of Figure ES.2) are four inter-related components: · Land development, which models the evolution of the built environment and the building stock. · Location choice, which models the locational choices of households, firms and workers. · Activity / travel, which simulates the tr~p-making behavior of the population.
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TCRP H-] 2 Final Report Figure ES.2 Idealized Integrated Urban Modeling System ~Demographics . I. - ~- -.~. . . . . . .- : - . --. - - . Regional Economics ~ - : . ~,.: ,, . . .. . ._ .__ ~.~ i. - ~ .... . . .. - . .... .. ~ ~ . . ~ . ~.~ .: ~ ~ : I: .~. ..~. . ~ I- . I...! Land Use ~, ~ - - - ~1 ., I. I. ... .. _ . ~ - ~ ~ . ~ .... .. ... Location Choice i: ~: _ I Government Policies 1 ~.1 : ~ ~ ~ ~ : | Auto Ownership Transport System ~ ~ .., .. .. . . - - . Activity / Travel and - ~ ~Goods Movement .. -. . I.. -A Flows, Times, etc. ~ExtemalImpacts - vat ::j ..
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TCRP H-12 Final Report · Auto ownership: this component models household auto ownership levels important determinant of household travel behavior. Points to note concerning these four "behavioral core" components include the following: . . The components are related. However, a properly specified model must distinguish clearly among the four components, since each involves very different actors, decision processes arid time flames. Each component involves a complex set of sub-models. Market-based supply- demand relationships tend to dominate aggregate behavior in each case, with prices both being endogenously determined and playing a major role in determining the outcome of these supply-dem=d interactions. Models that ignore these key supply- demarld interactions may fail to properly capture He dynamic evolution of the urban system over time. · The model must account for He ~nter-relationships over time. For simplicity, Figure ES.2 depicts the short-term impacts in which, for example, such factors as location and auto ownership generally are fixed. However, over time, these factors clearly will evolve in response to changes throughout the system (for example, people relocate Heir homes and/or jobs at least partially In response to accessibility factors, etc.~. . Auto ownership is considered here as an essential component to the process, rather Can as simply one more (often exogenously determined) input to the travel model. As Ben-Akiva  has observed, however, auto ownership is an integral part of the "mobility bundle" In that it is fundamentally interconnected with residential location and work hip commuting decision-makina. Figure ES.2 illustrates four major drivers of unbars systems, some of which may be treated as exogenous or endogenous to He model: Demographics, which is the evolution of the resident population. Regional economics" which is the evolution of the regional economy. · Government policies. such as zoning, taxation, interest rates, etc. · The trc~nspo'-tation system, i.e., the road and transit networks, etc. . . - Vll
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TCRP H-12 Final Report A series of technical axioms further develop the concept, in order to provide a basis for the 'ideal' model. With these axioms in mind, attributes of the ideal model then can be developed. These attributes are grouped according to three main categones: physical system, decision makers and processes. Land development, location choice processes, and job-worker linkages are all modeled as economic markets with explicit suppler and demand functions and procedures for price determination and "market clearings (i.e., the allocation of supply to demand). The model is envisioned to be dynamic, disaggregate and behaviorally sound. As such, it will be sensitive to a wide range of land-use and transportation policies, and able to trace the direct and indirect impacts of any of these policies through time and space. No attempt is made to specify detailed formulations of individual sub-models within the overall modeling system. Many options typically exist here, and much research is required in order to translate this very general mode! into operational practice. Similarly, no attempt is made to address the data and computational requirements of such a model, except to note that such a modeling system is almost certainly not beyond our current and emerging capabilities [Miller and Salvini' 1998]. ES.43 Inventory of Current Modeling Capabilities Given current technical capabilities (computer hardware and software' datasets and data collection capabilities; modeling techniques; theoretical understanding of behavioral processes, etc.), it is possible to develop and achieve the ideal integrated modeling system that was outlined in the previous section, with a concerted R&D effort. To start, a selection of existing integrated models was reviewed' in order to compare the current state-of-the-art with the ideal model. The reader should be cautious in Interpreting the review strictly as an evaluation of today's operational models. A more appropriate interpretation, and the one intended by the investigators, is that the review constitutes the taking of an inventory of what is available currently. The objective is to arrive at a description of the current general state of practice by examining in detail several representative models, rather than to identify a best or recommended model. It is fair to say that a significant number of 'integrated' or semi-integrated urban models exists around the world certainly in varying degrees of completeness and usability. Undoubtedly the three best known integrated models in the U.S. are: ITLUP (also often referred to as DRAM / EMPAL), MEPLAN and TRANUS. The three models have the following features in common: . · they are operational, commercially-available packages; each has an established history of use; and each has been applied in the United States in at least one practical setting (i.e., in an . . . - v~-
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TCRP H-12 Final Report MPO). Also of interest are Wee other models. These models are MUSSA, NYMTC-LUM and UrbanSim. These are noteworthy for two main reasons: . . each is currently operational, or sufficiently close to being operational, in a practical setting; and each contains a significant market representation (;.e., there is an explicit treatment of prices in land development). A detailed comparison of the six models resulted In four important conclusions: · All models are sensitive to transit - land-use interactions to varying extents. · All currently operational models fall short of the ideal model to varying extents. . . At the same time, current models individually and collectively display many strengths arid generally provide a solid basis for further evolutionary improvements. Despite Be scope for significant evolutionary development among existing models, a "new- generation" of ~nte:~,rated models must be developed In order to Filly achieve the ideal model. Newer models such as MUSSA arid UrbanSim point the way to more disaggregate and/or more dynamic models. However. much research and development must be undertaken In order to Filly achieve He ideal model. This must Include development of and experimentation w~ mode] structures Hat are designed explicitly to operate in a more disaggregate, dynamic, non-equilibrium framework. ES.5 Linking the Present With the Future: A Two-Part Approach How can the ideal fixture mode! be achieved? The Free aforementioned conclusions led to reco~runendations for a two-part programme: · Research and development pro gram directed towards producing the ideal -- 'next generations -- integrated model. · Evolution of existing capabilities and data, in order to maximize current potential. quickly and at minimal cost while m-ov~ng towards the ideal integrated model. This two-part approach reco~o~iizes Hat the ideal, next generation mode] cannot be achieved without a dedicated research and development effort. Although there is considerable potential in building upon existing capabilities and data, eventually the returns to scale will diminish. - ax
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TCRP H-12 Final Resort As a first step, Figure ES.3 classifies current and fixture land-use and transportation modeling capabilities. This classification recognizes that different cities are at different points along the evolutionary path. The classification is then used to identify development paws towards the achievement of Me ultimate long-teIm product; i.e., We ideal, next generation integrated model. Six Incremental levels (ending with the ideal model) are identified. In Figure ES.3, rows correspond to different levels of arouse modeling capability. While a continuum of levels obviously exists, five significant Cared use modeling States' or capability levels have been explicitly identified in Figure ES.3: L1. None. The planning agency does not in arty way mode! or forecast land-use. L2. L3. ActilJity +~udgement. Activity levels are estimated arid systematically allocated to zones, on the basis of considerable professional judgement. Non-markef-based land allocafior' model. A foment land use mode} is used, but this model is not market-based (i.e., it does not include endogenous price signals or an explicit supply process). IThUP is ~ example of this tripe of modei. L4. Land allocation wifI' price signals. A formal mode! is used, which includes endogenous price signals, but does not Include a fill demand-supply market process representation. This type of mode} does not currently exist. The potential role of such a mode! -- in light of the overall lone-term coal -- is discussed further below. --D ~-- by_ L5. Fully integrated markef-hased model. A full system of market-based supply- demand relationships with explicit prices is used. MEPLAN, TRANUS, MUSSA, NYMTC-LUM and Urbar~Sim are all current examples of this modeling approach, as is the 'ideal' model. Similarly, the columns in Figure ES.3 represent different levels of travel demand modeling capability, of which four are explicitly shovel: T . No transit or mode split model. Only roads arid auto travel are modeled. Transit with simplified (non-Io~~if) mode spin. Transit is represented in the modeling system, but modal split is performed using simplified (non-Iogit-based) methods. Assi~,nrnents are usually based on daily (24 hour). rather than peak-period, volumes, usually using some form of capacity-res~a~ned assignment. The modeling system is not usually iterated to achieve internal consistency.
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TCRP H-12 Final Report Figure ES.3 A Taxonomy of Transportation - Land-Use Modeling Capabilities \ Trave! ~(~) ~(~) ~) ~(~ L ]\ Demand ~ No transit/ ~ Pransit/ ~ Logit/ ~ an\Model ~mode split ~ no git (24 hr' ~ peak-period ~ Act vity-based | Model\1 l I ass~gnment _ t ~T~ '---~^T I None I| ~.~. :>Pg | =.' | 11 ~ ~1- 1 [ ~11 ~1 1 Judgem~ent I ff~=y!~r~-l~: ~ g, | , ~ I ~1 1~ - ~ Non-market-based ;~ >~; Land Allocation | | f ~l ~ %~ I f%' ~'. | ' .' 2. 8A~A ''. ';~, ~. . :3~, a.~~~.~ ' ' ·~ V r 2' ~,, ~ ~ l i _~_~g~ =~- <~ ~ Logit allocation | | | ~~$~: I 3 with price signals ~| |~1 r.-~ 1 1 1 ~"~' 1 -Ni' 1 Fullv l I | .':^~'c2cry<,~ >^^~- ~r~< Fi} st P ath ~ - 'Advanced' Path
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TCRP H-17 Final Report sign~fic~t gap, since it represents an important and attractive intermediate capability: either as an end-po~nt for some cities or as an important step towards a ~] market- based system (my. The L4 mode} is detailed in Appendix B of the Final Report. The advar~cement along We development paths also takes into account earlier recommendations; notably, those of the 1995 TMIP Dallas conference on land-use models. Specificity, the conference made seven recorrunendations for improving existing models. Each of these recommendations applies generally to Me achievement of the six incremental capability levels, as follows (adapted from S hunk et al. tI99541: I. GIS links are required. 2. Comparative descriptions, evaluations of existing models are required. 3. Time-senes validation of models are required. 4. Employment data must be improved. Better means of assessing mode] outputs are required. 6. Sketch planning me~ods for evaluating land-use - transportation impacts are required. 7. Improved feedback is required among existing land-use, transportation and environmental models. ~- ES.6 Research and Development Program Figure ES.4 summarizes the proposed Research and Development program for significantly improving the operational state of practice in integrated prearm modeling over the next five years. As shown in Me figure, this program consists of five closely related components: ~ . training of professional staff arid dissemination of technical information; 2. data collection, assembly, documentation and dissemination; implementation arid evolutionary development of existing models; 4. development of the "next generation" of urban models; arid 5. "non-model-based ' (complementary) research and analysis designed to - x~v improve both
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TCRP H-12 Final Report . our understanding of arouse / ~ansportahon interactions arid our ability to analyze urban policies. Components 3, 4 arid ~ represent largely parallel activities which typically would be undertaken by different groups of researchers, mode! developers, etc., depending on their strengths and interests. Components ~ and 2 components (training and data) support and are interconnected with all ether tasks -- for example "information flow" among the three parallel components would be maintained by the over-arch~ng information =d data dissemination components. The main features of each comportment are descnbed In the sub-sections below. . . . . . . · . . . - · it is important to note that We proposed Research and Develonment Program is designed to ˘ ~ r- -r - - - - - - - - -- - --- -- --r--- - - ~ - ~- encourage debate, as well as a multiplicity of opinions and contributions to the development of the 'ideal' integrated urban model. The intent is draw upon existing resources and knowledge bases, while building upon existing modeling capabilities. At Me same time, it is evident that the overall program must be coordinated, sponsored and promoted by a central body (or bodies). As well, specific activities (such as information dissemination) are clearly required at a single, national level, as opposed to multiple, sub-national diffusions. ES.6.! Support for Ongoing Implementation / Testing of Existing Models The Case study' approach is proposed. This a short-term action that both improves the current state-of-the-practice and provides crucial input to the development of the long-term ideal model. The approach is designed. in part, to address two common barriers to Me more widespread use of integrated models: the lack of in-house resources (i.e., insufficient expertise and money to implement a model), and the lack of well documented 'success stories which can encourage agencies to proceed win the modeling effort and can provide practical references. Benefits of Me proposed case study program include: · it directly improves Me state of practice in many locations; · it provides operational experience which can be extrapolated elsewhere; · it is a cost-effective means for controlled experimentation, and · it provides a practical, direct way to improve databases for both operations and research. - xv
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TCRP H-12 Anal Report Figure ES.4 Elements of R&D Pro ram for Integrated Urban Models ...-- . . ~ .: .. :~ . - ...: . . ~ .~..~:....- ~.~... Aft.. . ~ .. ~ . ~.~ I- ...~..~ - - ..~. . A..: -I- - ~ -::Tra~ning-of-Professional 'Staff/ I:niormation D.issemmation ·- ~-I ~ ~- -. - ~- . ~ :--- ~ -- .-~ - ~ - -A ~- - .. ~ :. . ~ . . .~ I, . . .. ~ ~.. ~. . . , ~ ,, ..... . . . . ~. . ~ . . -I . . . . . . ~ . . ~ ~ . .. .. .. .... . . . .. ~ . Support for On-going: .... . . . ImplementationlIbsting ~ ~ I. . . . .. .'.of~-~xisting::~lodels :' ..... ............ . . .. .. .. .. ~ - . .. ~ . . - - - .~ ... .. . . .. .. . . . ..... . . . I. I ~-, - . .. . .... , , ,. : s, . . .. . . ·':~'Case'.studies~n model .: ...... ~ . . -.: ~...~mplementaho.n -I ~-~ I. '.''2Acce'ss.to-daia,~results :.' ..~ .. . .... ~ ~ . ~ . .~,:'.~,:.~'docu~nentation' - i. ~:'~2 Encourage/support ~ ~ .... . . .. .. . ... .. ~ :evolutionary:- ::~: :~ .. .. .. . . . . . . . . . . . . . - ~ :~development of : ... . . . .... I:, . . - ..~--- ~ ~ ~ex~st~ng models : . ~ : ...~ . ;~.:. .:..~. C`Ne:xt Generations-:: :: . . . . ~ ... .... . - ~::~ :ModelR&D~: ::: . . . . . . . . . . · Research:prograln:,to:.: 'I .... . . ...... ....... . - - . develop '`.next -'.:.':''.. I:' ::.::..-.. ~ .:' ' .......... ........ ... . ... . . . . .... . ... . ' - aeneration~'--.or."'ideai" . ~. . .. : ............ ... . .. . ,i, ....... . . . . . .. .. .. ... ... .. Amos .e . : ~ ~ :-- : ~ : .. - . . · -A ~ ~ ~ ~ ~ -. --competltlve -:-~..~. :.- ~ ... - ...-.- .... ... ....... . . .. ... .. : - : Croat . 3asec : ~ :.::,:.-- :-:: - ~ ~ .. ..~ .. :: : -:-"s~ategically :' ..' .' :::'-:::-': . .. . .. ~ . .. ~ . :: ~ focussed" ~ '.-'': : '-hi :.::. '': ' - XV1 :: .~ .~ . : - ~ I. I. - - .: ' ~ ~.:--:~ ~ . . - :; : . ~ ~ - . : . - ~ .::.:-::- - if. If. . , ~ , : .- :. :::.: if- :~ I-:: . . .: I: : :: : ~ :: :: : :: :::: ~ :::: : ~ :: : ::: : i: ::: :: :::::: ::: : ::: ::::: :: I: :: ~ I:: : : i: :: : ::: : : : :: : : : : :::: : :: :::: :: :: : :::: :: :: :: ~: ~ ~: ~: ::~:DataAssembly,:~Documentaffon,~Disseniination ;~ . ~: ~:'| .: . ~. . ~- - . . ~ - ~ . : : . ~ ~:~ . ~-- - . ~ .- . ~ - ~- - - . . :~ . I: . . ._ _ : ~ - .... . --- . ~ :: . ~ . . :: : ~ ~If: : . . ~ :~: .. . . ~ . . . .. .. .:: --: - ::: i:-::: .:::-- :: .: -. .. : ~ I: . ~ ~ ~ -: : ::::: I: ~ ~I- - : - - ~ I- : ~ ~ ~ ~ ~ I:-: ~ . . -a : ~ . ;- . ..... ... - ~ - ~ ~ ~ - ~ ~ ~ ~ - I: ~ I: ~ --: ~ . . .- ~ -. - . . i ~ : - Case :smdles m morels- ~ ~ ~ ; . ... . . ~.. I- ~ .- -.~ - ~ ~.- .- ~ ~ - ~ . -: I* ~: : :: : . .:-. :.-:::. :: - . , :.-, LLt ~ to ~-· ~ :: - I. - : - .. . . ... . . : ,-i: ,: -: . - ~ - :: .:: :::: - :: : : :::: . :-:: ' Development -of none :::: .~ . .~-.. ~ A. .- - ... ;. . I, .-. I... ~ model}ngtools:- -: ~ : : : .. . . . . . . .. . .. . . . . . . . . . .. .. .. . . . .. : - Qualitative policy ~ ~ :: : ~ . .. ~ . ... ~. . . . . . . . . . . : =:a yeas- ~ ~: ~ -- : .... . .. ... .. . . . . . . . . . . . - ~ . .~. . a ... . ~ . .. ..... . .. ... ... ~mp~nca . ~e. Aura . . ~ ...... .... . ..... . . . . . . ... ..... . ~.. I .. . ~i.alysls - . .. .. . .. ...,.. I.. : :~:::~:-: Other R&D: ... .. .. .... : ~ : : I:
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TCRP H-19 Final Report ES.6.2 Development of "Next Generation" Models The "ideal" or "next generation' model wall not simply evolve out of the current set of operational models. As with TRAN SIMS (~e next generation acti~7ity-based travel modeling system, now being developed under TRIP), the next generation of integrated urban models must be developed through an explicit dedicated and aggressive R&D effort, if they are to be developed in a finely fashion. Indeed, given Weir expenmen~ nature and the level of effort required to develop and implement them, it will only be Trough a concerted, funded R&D program that such models can be developed at all, since this effort clearly lies well beyond the capabilities and resources of virtually all local (and even state) planning agencies. Such a R&D effort should consist of at least the following three su~components: 1. basic research addressing fundamental methodological arid behavioral questions which need to be resolved if next generation models are to be successfully developed arid deployed; 2. development of mothering system prototypes; arid 3 . implementation and testing of models in operational settings. Each of these steps is critical to the eventual successful Implementation of next generation models in operational planning applications. Of these, 'basic research' is often Me most difficult for agencies to support' given Mat they typically are anxious to move towards working models. As a result, there has been a chronic tendency in the transportation field to rush into mode! development. The inevitable result is that we make assumptions very early in the model design process about what modeling methods to use (usually Me "mea and true"), about how to represent behavior (usually in a simplified manner to reduce model complexity), and about what data to use (usually what are available, which are not necessarily what are needed). The net result is usually a very conservative approach to model development, focussed on generating a working model within a fixed period of time. Such an approach is not conducive to innovation, to testing hypotheses, and to developing fundamentally new approaches to modeling urban processes. A potentially long list of basic research topics exists. Example topics include: microsimulation of land markets; demographic sepsis and updating (especially household formation and evolution); supply-side modeling (e.g., developer behavior); goods movement' linkages between regional macroeconomics and spatially micro processes; , . - XV11
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TCRP H-19 Final Report micro-scale urbar1 modeling; linkages to activity/trave] models; dealing with dynamics (short- vs. long-run processes; feedback; reaming; "optimal" time steps); and determination of an "optimal" level of spatial resolution. The division between mode! protolyping and mode! implementation can be somewhat arbitrary. The argument, however, is that fundamentally new models do need a carefully staged implementation process. This begins with smaller-scale testing, quite possibly of model sub- systems before fi~-scale implementation is attempted. In particular, prototyping allows experience to be gained With the model. sub-systems to be tested, and mode} weaknesses to be uncovered and corrected, prior to 'locking into' the full-scale, implemented version ofthe model. The TRANSIMS mode! development process provides a good example of this approach. Here, both the Dallas and Portland, Oregon case studies are providing important intermediate tests of the TRANSIMS concept prior to the anticipated full deployment of the model. This R&D program should be strategically focussed. This means that it should have as its explicit goal the development of next generation moclels which approach the ideal model as closely as possible, and it should only support projects which clearly aIld substantively contribute in a coordinated way towards achieving this goal. At the same time. the program should be tactically broad, so that it does not prejudge the methods or Mores which wall 'best support next generation models arid that it is open to a diversity of researchers and research organizations. ES.6.3 Other Research and Analysis In addition to the formal modeling tasks discussed in the previous two sub-sections, several other research tasks are directly supportive of improved transportation - land-use analysis and planning. These were identified within this project and elsewhere. Examples include: . . Case studies documenting the evolutionary development of improved transportation - lar~-use modeling methods within MPOs. Development and implementation of the 1!ogit, price-signal-basect lands allocation mode! described in Appendix B. (This represents land-use capability L4, as shown in Figure ES.3 and discussed in Section ES.5.) · Development of various simple tools and procedures for use in situations in which formal integrated urban models are not available (e.g.. small urban areas, or as an interim measure in larger urban areas that currently lack an integrated urban modeling capability). . ., - xv
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TCRP H-12 Final Report Development of recommende~procedures for developing employment databases in urban areas where such data currently do not exist (a major obstacle in many urban areas to mode! development -- and to planning analysis in generai). Review of Zand-use and transportation policies, Weir e0iechveness and the processes used to analyze ~em, as well as the relationship between policies and modeling (i.e., between qualitative and quantitative analysis). ES.6.4 Training and Information Dissemination A major barrier to the implementation of ~nte~,rated urban models is a lack of trained staff in MPOs who can properly use these complex models. Here, "trained" not only means experience with the mechanics of running a given software. Much more important, the term also means having a sufficient technical understanding of the behavioral arid methodological foundations of the modeling system, so that staff cart apply appropriate judgement in operating the model and interpreting its results. Such training cart be supported by a number of actions, including: Short training courses and seminars. · . .. ~, .. . . These could address both theory (e.g., macroeconomic theory or market behavior, random utility models of human decision- makina, transportation - land-use interactions, etc.) and practice (e.g., an overview- of current and emerging integrated urban modeling practice, the application of integrated models to practical situations, etc.~. Development of "best practices " manuals, case study reports and other aids for self- lea~nin~ and reference. . Development of a manual on sketch planning methods for integrated land-use transportation analysis; perhaps along the approach of a 'quick-response' system. · Literature reviews on selected topics not dealt with elsewhere. . . Dissemination of the documented results of the implementation case studies and other R&D efforts described in Be previous sub-sections. "Integrated modelers' users group'' for the exchange of information, problem solutions. etc. · Promotion of 'special Interest groups organizations such as the Amencan Planning Association, etc. - X1X ' among parallel/related professional
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TCRP H-19 Final Report The development =d maintenance of a well advert~zed web site also is proposed. The web site would provide Mariners web access to a centralized library of information conceding integrated urban modeling. It also would also provide a central contact point for the proposed users group. Information contained within the web site could include: all reports arid over documentation generated by the R&D program described above all manuals and other training materials; documentation of existing models; and literature reviews, annotated bibliographies, etc. ES.6.5 Database Assembly and Management Data limitations may well be the single most often cited obstacle to the development of operational integrated urban models, as well as to research efforts in this area. One of the single biggest contributions which a coordinated R&D effort can make is to improve the national database for transportation - land-use analysis and modeling. This can be achieved through three key activities: . Development of a centralized data library. The library would contain well- documented databases from a number of urban areas. As a condition of funding support for any of the R&D efforts described above, we propose that the complete mode} database (land-use and transportation) should be provided, suitably documented, to the central data library. These documented databases would then be available to any researcher or planner who wishes to access them. The data library is critical In supporting the evolution of integrated urban modeling, since it promotes: o cross-city comparisons of transportation - land-use interactions, 0 tests of mode] transferability, in which a given mode} is applied to multiple locations. 0 cross-testing of multiple models within one or more urban areas; and o the development of national default parameters and relationships. While the exact contents of these databases wall inevitably vary Mom one urban area to another, it should prove possible to impose minimum standards upon their contents and structure to facilitate the sorts of comparative analyses described above. · Development of data collection stanclards and procedures, especially with respect to critical data items that currently are often not well handled in many urban areas. , , - xx
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TURF H-12 Final Report This might include developing recommended procedures for using tax assessment arid/or real estate databases to support modeling activities, procedures for collecting and maintaining employment databases; and, possibly, procedures for collecting goods movement data Assistance for selected data collection efforts. ., -- While generalized, nation-wide support for data collection is probably beyond the budget of even the most extensively n3naecl program' very Iocusseo running of special' high-return data collection efforts should prove to be very cost effective. One example is the development of a very high quality micro-level database for portions of one or more cities to support R&D efforts wad respect to micro-scale modeling [Deakin arid Lathrop, forthcoming. Another example is support for pilot-testing of novel data collection methods, particularly if Hey abbess one of the traditionally problematic data items (employment, price data, firm location choice, etch. ES.6.6 Program Management The development of Be R&D pro~a,rarn requires both a sponsor and a means of managing the work. It is reasonable to expect that these would be one and the same agency. In this way, the sponsoring / managing agency will be able to: · maintain budgetary and adm~rus~ative control; keep the program on Lack, and move it forward; serve as a cleannghouse for He exchange and dissemination of products, information, etc.; liaise vow over, related efforts (notably, other TMIP tracks, but also TEA-2 i ), and provide a voice arid a profile for the program. However, in addition to the admini~s~ative / budgetary management, a technical management function also is required. Clearly, all of these functions must be linked. However, we propose that a separate technical management body be established, under the direction of the administrative / budgetary management body, with responsibility for the following: the independent peer review panels, which would oversee the case studies (see Section ES.6.1), technical coordination and specification of all aspects of the R&D program, including: development of technical specifications for each activity, development of ~goodness-of-fit' criteria for each activity; - XX1 -
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TCRP H-17 Final Report o o o o ensure technical consistency among the disparate activities; technical evaluation of contractor proposals for conducting each activity; oversight and review of each activity; and technical advisory services to the mar~ag~ng agency. The independent peer review. pane! for the case studies and the technical management function could be one and the same. Or, a separate peer review pane! could be established for each case study, perhaps under the direction of (or at least with the advice of) a member of the technical management function. This increases the central managers requirement, but has the advantage of bringing more participants into the process while spreading the technical burden. It also is conceivable arid even desirable, Cat the contractor (modeler) for one case study could serve on the peer review panel for a second case study. ES.6.7 Budget and Time Frame Table ES.! presents a recommended budget for the R&D program proposed above. Attempting to develop a budget based on this still very general discussion is difficult, and requires a number of assumptions. The most basic of these is the assumption of a five-year time period for the program. The choice of five years is clearly arbitrary. and could be changed without significantly altering the overall logic of the program. It is assumed, however, that five years is about as a Tong a period as government agencies are likely to be w~ling/able to commit to an individual program. At the same time, it must be recognized that a concerted multi-year effort is required if significant progress is to be made in this long-neglected field. In particulars five years is actually quite a short period of time to accomplish the development of operational 'next generation' models. Table ES.! Recommended Budget, Five-Year R&D Program t11~ 1 :~.~1 ^ ~ ~iu~ 1 ~; } ~.~ ~ 1 i ~; I 1 1 1.50 T 1.00 1 0.0 1 0.30 1 0.30T 330 1.50 1 1.00 1 0.20 1 0.20 1 0.201 3.10 1.30 1.50 0.20 0.20 0.203.60 1.25 1 1.50 1 0.20 1 0.20 1 0.201 3-35 .25 2.00 0.20 0.10 0.102.65 L 6.00 1 7.00 1 1.00 1 1.00 1 1.001~6oO 2 3 4 5 Total Note: Allf gures are in millions of dollars . . - XX11
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TCRP H-12 Final Report Given We high degree of variability and uncertainty which exist with respect to the cost of one project versus another (implement model X in city Y. test N sub-components of a yet-to-be- designed next generation prototype model Z), these dollar amounts represent "reasonable judgements" concerning how much should be spent in order to have a significant impact on the integrated urban modeling state of practice and art over the next five years. Much less than these amounts will not generate the level of improvement in modeling capabilities which are desperately needed; while expenditures considerably in excess of these amounts most likely will not be cost- effective at this point in time. As detailed in Table ES.l, we recommend an expenditure of $16 million over a five year period, for an average expenditure of $3.2 million per year. Over 80% of this ($13 million) is allocated to current and next generation model development and implementation, with the remaining $3 million (just trader 20%) allocated to supporting R&D activities. We believe the recommended budget is appropriate to sustain and move forward the recommended R&D program towards the development of practical tools. The proposed expenditure fillly complements TRANSIMS and the other TMIP tracks' thereby moving the TMIP picture to completion. It also expands significantly the current minimal level of research support, which is a necessary condition towards achieving the stated Track E objectives. Moreover, it is also an extremely small sum compared to the billions of collars that are spent annually on transportation and land-use investments In the United States. . . . - xx
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Representative terms from entire chapter: