PROPOSAL TO THE MINETA INTERNATIONAL INSTITUTE FOR SURFACE TRANSPORTATION POLICY STUDIES 

APPLYING AN INTEGRATED URBAN MODEL IN THE EVALUATION OF TRAVEL DEMAND MANAGEMENT POLICIES IN THE SACRAMENTO REGION : YEAR TWO

March, 2000

Principal Investigator:

Robert A. Johnston, Professor

Abstract:

We have applied a test version of an integrated urban model (travel and land use) to the Sacramento, California region over the last five years. In order to make the model more sensitive to Travel Demand Management (TDM) policies, such as transit and compact land use, in Year One of this project, we are making several improvements to the model. We will then run a range of policy scenarios for interest groups in the region. These findings will then be brought into the regional transportation planning process by these groups. In Year Two, we wish to further improve the model by adding submodels for floorspace and for heavy truck freight. We will also interface the urban model with our geographic information system (GIS) model, to permit the citizens groups to select areas to protect from development and to portray the land use maps for the future transportation scenarios. We will also add a traveler welfare measure. This measure of net benefits allows us to see impacts on households by income and so judge equity. The improved model will then be used to simulate further regional transportation scenarios with the environmental group and the equity group with which we currently cooperate.

Background:

The Sacramento Metropolitan Planning Organization (MPO), SACOG, like most in the U.S., is proposing to build more freeway capacity, while at the same time improving transit service. In many corridors, the roadway expansions will compete with the rail expansions. The major increases in accessibility are on roads, due to new carpool lanes, a new bridge, bridge widenings, and new expressways. There is no long-range plan for good transit coverage. The overall investment "strategy" is geographic equity, spreading the funds around. Compact land use policies have been explicitly rejected, as a regional policy. Recent studies, leading up to the 1999 regional transportation plan, seem to be laying the groundwork for new concentric freeways, to connect suburban employment centers. Two such outer beltways were rejected in the 1980s, but the MPO seems now to be advocating them as needed, by emphasizing the need to connect suburbs directly, while at the same time finding that transit is unlikely to work for these trips. This is traditional thinking, where the travel demand patterns of the past are projected into the future and then the MPO tries to "meet" these "needs."

SACOG, like all MPOs, runs their travel models only out 20 years, which does not permit one fully to see the land use effects of expanding road capacity in outer areas in the region. They also use only one land use projection for modeling all policies and so the travel-reducing land use effects of transit policies are not represented.

The most serious problem in this region, in our opinion, is the falling incomes of the lower half or three-quarters of households by income, a long-term trend statewide. Furthermore, the region has lost employment in low-skilled jobs and also has lost employment in the inner areas, greatly disadvantaging these households. These problems were also indentified by a Sacramento Housing and Redevelopment Agency study on economic growth in the region (SHRA 1997). We have adapted a traveler economic benefits model that we run using calculations from the SACOG travel model. It projects changes in net benefits to three household income classes and so is useful for equity analysis. We have done about 30 scenarios for the year 2015 using this travel model set and have found that freeway widenings do not favor lower-income households, whereas transit improvements do, if accompanied by density increases around the light rail stations and good feeder bus service to the rail stations (Johnston, Rodier, and Choy 1998; Johnston and Rodier 1999). We are currently performing a welfare-to-work transportation study in the region.  SACOG does not analyze equity effects of its transportation plans or projects.

The SHRA study interviewed a large number of local decisionmakers and leaders, both  public and private, and found that the most important problems in the region were regional planning, transportation, education, and quality of life. Fiscal disparity among localities and geographic segregation of households by income were found to contribute to all these problems. SACOG does not address these two underlying problems. With our urban models, we can simulate open (deregulated) housing markets, regional tax sharing, and improved schools and lower crime rates in inner city areas, to see how these policies may help increase transportation equity. The SHRA survey indicated a fair degree of consensus from respondents across organization types on these underlying problems and a desire to advance toward regional coordination of land use planning and the consideration of regional tax sharing. The business groups now carrying on from the initial SHRA survey and recommendations, however, have narrowly construed their charge and are not examining land use planning or tax sharing or fiscal disparity.

Two nontraditional interest groups are now becoming involved in transportation planning in this region, ECOS, an environmental umbrella group, and SAC-TE, an umbrella group of neighborhood and social equity groups. We at UC Davis have begun discussions with leaders of these groups about improving our existing urban models and running long-range scenarios, to the year 2040. Whereas we operate the most advanced model in the region, one that represents the land use effects of transportation policies, we need to improve this urban model (MEPLAN), so that it represents all relevant travel and locational behaviors.

A major shift in thinking about travel demand has been occuring over the last ten years. The realization that auto travel can be induced by adding roadway capacity was firmly established by the United Kingdom SACTRA report in 1994 and acknowledged in the U.S. by the Transportation Research Board (TRB) Special Rept. 245, Expanding Metropolitan Highways, in 1995. Demand for auto travel can be induced by adding roadway capacity and it can be suppressed by letting roadway congestion worsen, by road tolls, by developing transit service, and by compact and transit-oriented land use policies. Regional transportation modeling has not caught up with this new way of looking at demand. Almost all MPOs in the U.S. use outdated travel demand models that do not represent changes in number of trips, trip lengths, auto ownership, time of travel, and land development due to changes in transportation policies.

Our Year One work improves an existing urban model to include all of the travel and locational behaviors. We then will test TDM policies with the citizens groups.

The Year One Research Now Underway:

We operate an integrated urban model, MEPLAN, on the Sacramento, California region. This model was calibrated on datasets for this region and run on four scenarios for the year 2015, under previous funding. The model represents route shifting, mode shifting, changes in trip generation and trip lengths, and land use changes.

To be fully sensitive to the complete range of Travel Demand Management (TDM) policies available, regional models must represent all household behaviors affected by such policies. We are adding an Auto Ownership submodel to the urban model, so that the effects of TDM policies on household auto holdings can be represented. We are also adding a Departure Time Choice model, so peak spreading can be represented. The first will draw on the Auto Ownership submodel in the SACOG travel model, which we operate, and the underlying datasets. The second will involve drawing from applied work in other regions, such as Edmonton, and on academic models.

In addition, we are making two other improvements to MEPLAN that will make it more useful for evaluating TDM and other transportation policies. 1. We will recalibrate it on selected 1980 datasets, in addition to the 1994 database it is currently calibrated on. We will also validate the model on selected 1999 data. This exercise will make the model more accurate, overall. 2. A third residential density category will be added, so that rural residential development can be more accurately represented. This work will be accomplished by John Abraham, with advice from Doug Hunt, professor at U. of Calgary, the only licensee of MEPLAN in North America. The UC Davis team will develop, clean, and transmit datasets to the MEPLAN team. With these improvements, MEPLAN will be the most comprehensive urban model in the world, in terms of representing all behaviors affected by transportation and land use policies.

After testing the improved MEPLAN, we will rerun the four scenarios we have already run and evaluate the results, for 2015  (No Build, New High Occupancy Vehicle  Lanes, HOV Plus Beltways, and Light Rail, Buses, and Tolls). The results from this previous work with MEPLAN were generally reasonable (Abraham and Hunt 1999a; Abraham and Hunt 1999b). We will also run scenarios for 2040, for the first time. This work interrelates transportation, land use, and the economy. The MEPLAN vehicle activity data are fed into the DTIM2 California emissions model, to get mobile emissions. MEPLAN also includes data on land consumption and numbers of households and employees per zone, as well as land prices.

We will then take these results out to several community groups, including ECOS and SAC-TE. We will determine if they consider the results reasonable and the model trustworthy. We will also identify other scenarios they want us to run. Based on these meetings, we will run the requested scenarios. The new version of MEPLAN runs in Windows and ArcView and network editing is easier, so scenarios with different road or transit networks can be programmed  done in our lab at UC Davis.

We will then meet again with the groups  and evaluate the scenarios with them. This will lead to a detailed writeup, recommendations for the region (really a discussion of which groups favor which scenarios for what reasons), and recommendations for modeling at SACOG. This research project may lead to SACOG being asked by some or all of the outside groups to use MEPLAN.

In Year One of this project, so far, Johnston has met with the two citizens groups once in general discussions, was an invitee to the Sacramento Bee newspaper editorial board meeting on transportation in the region that resulted in a two-page article, has met another time with the Bee board, has helped the Sacramento News and Review with an  article on regional growth, and was the expert affiant in a suit brought by ECOS and the Sierra Club against SACOG claiming inadequate analysis of the emissions in the last regional transportation plan. Johnston also has been invited by SACOG to present his geographic information system (GIS) urban growth model to their citizens advisory board for possible application in their current metropolitan transportation planning process.  Johnston sits on the SACOG modeling advisory committee and is preparing a paper with the chief modeler at SACOG comparing four urban models applied in the region. Prof. Johnston has also published an op. ed. piece in the Bee calling for revisions to state laws that discourage jobs-housing balance and compact growth. Johnston and staff recently met with the citizens groups to go over the scenarios run in the past work and to identify their preferred scenarios for the region. This work is informed by the recent Bay Area report by citizens groups there, calling for improved rail transit, express buses, compact growth, and jobs-housing balance.

 Work Proposed for Year Two:

In Year Two, we will make further improvements to MEPLAN. First, we will add a floorspace model. This work was proposed in Year One, but the data are not in good shape and so we need more time to interview real estate experts to get estimates of floorspace supply in each zone and estimates of lease rates for each type of economic activity in each zone. The floorspace model is important because it directly represents land use controls (on floor area ratio) much better than our current model, which only represents the density of persons or employees per acre. Second, the floorspace model permits us to represent building types occupied by each economic activity type, and so when activities attempt to move in successive years they must pay to renovate buildings designed for other activities and so this retards the relocation of activities in a realistic fashion. Past model runs with MEPLAN have excessive movements of activities over time. Also, the floorspace model will permit a more accurate depiction of rents by zone and, therefore, of the effects of policies on housing affordability, a major concern in regions examining transit and compact growth policies. We will gather the data for this model and the work will be done by John Abraham, with guidance by Doug Hunt, in a subcontract.

Second, we wish to add a heavy truck freight model to MEPLAN. This will be based on the SACOG truck travel survey data and truck volumes and on the SACOG origin-destination tables from their existing freight model. We will collapse the trip tables to fit our district travel model with its sketch network. A freight model improves the accuracy of estimates of economic benefits in scenarios, because if road congestion is reduced, freight delivery is speeded up and time costs reduced. Heavy trucks are worth several times what an auto is, per hour. We will gather the data for this model and the work will be done by John Abraham.

Third, we will apply a traveler welfare model to MEPLAN that we previously developed 

for the SACOG travel model. This model measures the net economic benefits to

households from a future policy scenario, compared with the future trend scenario. We

use the Small-Rosen compensating variation statistic (which is like consumer surplus)

and have gotten reasonable results in several past studies with the travel model (Rodier

and  Johnston 1998). There are three household income classes in MEPLAN and so we

can do a vertical (income) equity analysis of the scenarios. We will develop this

statistical model and John Abraham will implement it in the MEPLAN code.  

Fourth, we will interface MEPLAN with our geographic information system (GIS) land allocation model. Then, the citizens groups can use the GIS to determine which lands to protect, such as habitats and floodplains, before running MEPLAN. Also, the district land use results from the transportation scenarios run in MEPLAN can be disaggregated in the GIS for mapping (into half-acre grid cells). This helps citizens understand the land use effects of the transportation policies. We have developed a rough version of this method already. The GIS model is easy to change, due to the way we designed it. All maps and output data tables will be posted on our Web site. We intended to do this in Year One, but SACOG was very late in getting their data to us.

TheseYear Two improvements will increase the accuracy with which we can simulate induced travel by including heavy trucks. The improvements will also increase our ability to measure the equity effects of transportation policies on land rents and on traveler net benefits. Last, adding the GIS model will improve the representation of the results, so lay citizens can better understand them.

Dissemination:

We will write up our practical findings on the performance of the scenarios, our methods findings regarding MEPLAN and the improvements made, and the process of working with the various groups. These results will find their way directly into policy circles, as the Principal Investigator is a member of the Transportation Research Board (TRB) Committee on Transportation and Land Development, advises a member of the Travel Model Improvement Program advisory committee, advises EPA on the conformity regulations, and is an expert affiant for the Chicago lawyers on the freeway lawsuit.  Papers will be presented at TRB and other meetings and published in widely read journals.

Practical Value of This Work:

Travel demand management policies, such as transit and compact land use, or tolls, will tend to not get adopted if they are modeled with the current generation of  inadequate travel models. These models do not represent most of the behaviors that occur as a result of TDM policies and so underproject the travel reductions and economic benefits of such policies. Many other regions in the U.S. will adopt urban models in the next few years. These models should be improved to include the capabilities that we will build into MEPLAN  and demonstrate in this project. Such models will be much more sensitive to TDM policies and so will greatly assist in accurately evaluating transit, supportive land use policies, parking charges, and tolls.

Tasks and Dates:

1. Task One: Collect, clean up and assemble all datasets needed for model improvements.             July 1, 2000 – August 31, 2000

2. Task Two: Make improvements to MEPLAN.

            September 1, 2000 – September 30, 2000

3. Task Three: Rerun scenarios and evaluate results. Recalibrate submodels, if necessary.

            October 1, 2000 – October 31, 2000

4. Task Four: First round of meetings with community groups.

            November 1, 2000 – February 28, 2001

5. Task Five: Make improvements to TRANUS, if necessary. Run additional scenarios.

            March 1, 2001 – March 31, 2001

6. Task Six: Second meetings with community groups.

            April 1, 2001 – April 31, 2001

7. Task Seven: Draft final report to IISTPS.

            May 1, 2001 – May 31, 2001

8. Task Eight: Draft journal articles. Finalize report to IISTPS.

            June 1, 2001 – June 30, 2001

9. Task Nine: Get approval of journal articles from IISTPS.

            July 1, 2001 – July 31, 2001

10. Task Ten: Present papers and submit to journals.

            August 1, 2001 – December 31, 2001

Draft Budget:

Period: July 1, 2000 – June 30, 2001

R. Johnston, Research Assoc., 80 hrs. @ $50/hr.                                                          $4,000

Student Assistant (data and GIS)                                                                                   $15,000

Student Assistant (MEPLAN)                                             $15,000                                                                             

Subcontract to John Abraham                                                                                       $10,000

                                                            Total for this Proposal:                                 $44,000

References:

Abraham, John E. and J. Douglass Hunt 1999a. Firm Location in the MEPLAN Model of Sacramento. Transportation Research Record 1685, pp. 187-198.

Abraham, John E. and J. Douglass Hunt 1999b. Policy Analysis Using the Sacramento  MEPLAN Land-Use Interaction Model . Transportation Research Record 1685, pp. 199-208.

Johnston, Robert A. and Caroline J. Rodier 1999. Synergisms Among Land Use, Transit,

and Travel Pricing Policies. Transportation Research Record 1670, pp. 3-7.

Johnston, Robert A. and Caroline J. Rodier 1998. Regional Simulations of Highway and

Transit ITS: Travel, Emissions, and Economic Welfare Effects. Invited paper for J. of

Mathematical and Computer Modeling. Vol. 27, nos. 9-11.

Johnston, Robert A., Caroline J. Rodier, and Melanie Choy 1998. Transportation,

Land Use, and Air Quality Modeling, pp. 306-315 in Transportation, Land Use, and

Air Quality: Making the Connection, ed. by Said Easa and Donald Samdahl. American

Society of Civil Engineers.

Johnston, Robert A. And Raju Ceerla 1995. The Effects of New High-Occupancy

Vehicle Lanes on Travel and Emissions. Transp. Res.: A 30:1, pp. 35-50.

Rodier, Caroline J. and Robert A. Johnston 1998. Method of Obtaining Consumer Welfare from Regional Travel Demand Models. Transportation Research Record 1649, pp. 81-85.

SACTRA 1994. Trunk Roads and the Generation of Traffic. U.K. Dept. of Transport. London.

SHRA. 1997. Sacramento Housing and Redevelopment Agency. Phase I Vision Project: Urban Area Economic Development Plan for Metropolitan Sacramento, California Region. Sacramento, CA. 

TRB 1995. Transportation Research Board, Expanding Metropolitan Highways. National Academy of Sciences. Washington, D.C