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extremely quickly. Options to âtransportingâ are becom- ing more viable. Spatial, separation, and mitigation activ- ities must be the base for forecasting. Pricing and economic models are becoming more varied and complex. Available technologies are shortening the response times and the dispersion times. These items need to be examined in travel demand modeling and may impact the fundamental assumptions and parameters that are being utilized. The baseline may be changing in the mod- eling process. There is a need to evaluate radically differ- ent scenarios. There is also a need to be able to quickly accommodate changing baselines. There are a number of transportation planning issues and questions that cannot be addressed by current travel forecasting models. There are a range of questions stem- ming from opportunities related to technology, institu- tional change, and broader social and environmental change that challenge the capabilities and the range of predictive powers of models currently being used or envi- sioned in the future. I think this is an issue that needs to be addressed in the long term. To help address this issue and other concerns, the travel modeling community needs a comprehensive and coherent view of the range of demands being placed on travel models. This approach means establishing a top- down process that begins by inventorying capabilities, identifying needs and potential needs, and moving toward a balanced research and application perspective. To help bridge the gap between current model practice and innovative model research, the travel modeling com- munity should establish a program to further identify development and deployment goals. Research, demon- stration projects, and funding should be tied to a consensus- driven program that represents the best assess- ment of methods to address future forecasting needs. There is a need to increase resolution and focus on spe- cific time- of- day models. Other areas of need include the ability to forecast turning movements, evacuation plan- ning, transportation demand management analysis, and congestion management. Enhanced capabilities in trans- portation system management and intelligent transporta- tion system deployment and evaluation are also needed. Safety planning, submode analysis, and interim improve- ment planning and analysis highlight other needs. It is important that travel modeling focuses on more than just transportation. The framework of analysis is becoming increasingly comprehensive and travel models are being asked to predict travel impacts on the entire social fabric. Examples of these expanded social issues include environmental justice; land use economics and location; urban planning; system operations policy; and air, noise, and water quality. We also face increasing complexity in understanding needâoption relationships. Markets are more complex with diverse supplyâdemand relationships. There is greater interplay today between public and private own- ership and management of different modes of the trans- portation system. INNOVATIONS IN MODELING Brian Gardner Other speakers have highlighted many of the issues that need to be addressed as we work toward improving both travel demand models and the use of new modeling tech- niques. Examples of model enhancements include addressing future land use changes, activity and travel budgets, and departure time and peak spreading. Being able to assess traffic operations impacts, including traffic control and queuing, is also important. A number of factors appear to be influencing the slow movement toward widespread application of new travel demand models. There is a perceived lack of need in many areas due to institutional issues and market iner- tia. There is sometimes a lack of interest in using models beyond meeting federal and state requirements. There are limited data on the benefits of using new models. There is limited quality assurance and quality control on some travel demand models. Finally, many MPOs and areas face staffing and financial limitations. There are also factors pushing for change, however. First, there is more stress on the policy and investment decision process in many areas. The growth in demand for travel in all sectors is outpacing the growth in supply. Active, well- informed stakeholders with competing agendas are pushing for better data and better models. Policy makers and all groups are faced with more com- plex decisions. Let me suggest a few areas on which we should focus our energy and resources. First, there is a need for accu- rate data programs to support the â3Câ planning process. We must understand key regional travel markets and support best- practice model validation. Second, it is important to improve model quality assurance and qual- ity control methodologies. Third, we need to make the results from the travel demand modeling process more useful and understandable to policy makers and stake- holders. Finally, we must do a better job of incubating new travel demand modeling technologies and methods. To help advance the state of the practice, we need to improve access to new tools through licensing, distribu- tion, teaching, and research. Practical documentation of the new travel demand forecasting tools and techniques is also needed. Case studies using real issues and real data, as well as published peer review findings, are required. Bruce Spear, Federal Highway Administration, moder- ated this session. 12 INNOVATIONS IN TRAVEL DEMAND MODELING, VOLUME 1
