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TMIP Email List Technical Synthesis Series 2007-2010

Fuel Price Synthesis: Potential Travel Model Considerations

Throughout the years a recurring discussion on the email list is the variety of travel model considerations to be addressed when accounting for fuel price changes. The ensuing diversity of comments (regarding potential behavioral responses to prolonged higher fuel prices) demonstrates the extent with which fuel price changes could eventually impact current modeling practice. Five key questions posted to the email list during different periods serve to define potential travel model considerations given higher fuel prices:

Where there are few recommendations offering tangible solutions or practical examples to address the questions noted above, the discussion elicits a number of suppositions and observations on how select model input variables might require adjustment. Taken as a whole, these comments highlight the diversity of issues that eventually may need to be addressed in travel model development.

The following synthesis represents a compilation of all emails on the subject matter since the inception of the Travel Model Improvement Program (TMIP) email list.

Potential Travel Model Considerations

The synthesis describes six probable travel/land use related scenarios that may occur if fuel prices and auto operating expenses increase significantly for a sustained time period. These are:

Additional travel model considerations were offered that might require a re-assessment of certain model input variables; these are listed below:

Potential Travel Model Solution

One significant solution offered to the email community was to incorporate a feed-back between fuel costs and land use/demographics to account for the changes in travel related expenses, even though this is not a trivial endeavor. Understanding the underlying assumptions and correctly identifying the numerous land use-transportation dynamics associated with the cost of travel and determining the orders of magnitude and analytical approaches to interpreting the results are simply unknown at this point. Based on the contributions to the email list, it appears that beyond the realm of academia, these types of models have not been integrated into current mainstream travel model practice.


Each of the potential travel related outcomes and model considerations noted above are recommended for careful consideration; however, there are relatively few concrete suggestions on how to account for these issues in the current model practice with a high degree of certainty. Based on available observed data, the modeling community has a limited ability to model the potential consequences of higher fuel prices on overall travel. As one contributor offered, modeling the effects of the cost of driving hasn't really been adopted because large scale changes in response to fuel price changes have never occurred and therefore, the true effects are hard to establish. Moreover, it is simply too speculative to predict whether market constraints and innovations will drive up or down the relative costs of driving over time.

November 2007


The objective of the series is to provide technical syntheses of current discussion topics generating significant interest on the TMIP e-mail list. Each synthesis is drawn from e-mails posted to the TMIP email list regarding a specific topic. The syntheses are intended to capture and organize worthwhile thoughts and discussions into one concise document. They do not represent the opinions of FHWA and do not constitute an endorsement, recommendation or specification by FHWA. These syntheses do not determine or advocate a policy decision/directive or make specific recommendations regarding future research initiatives. The syntheses are based solely on comments posted to the e-mail list.

Updated: 04/14/2014
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