Investigation of an empirical methodology for linking value of time with census tract median income

This research examines a new methodology for prospectively estimating thewillingness of travelers to use a toll road by combining travel time saved with theincome of the prospective customer base. The purpose of the research is to facilitatenetwork level planning by allowing some reasonable predictions of acceptable toll ratesfrom readily available data and estimation techniques. Methods of estimating userbenefit resulted in simulated distributions of value of user time. Values of time arelinked to census tract income data for the user population to produce value of time as apercentage of income as an indicator. As relevant literature acknowledges the tendencytoward increased toll road usage at higher income levels, it is hypothesized that linkingestimates of value of time directly to household income would produce a more usefulindicator of the travel market than do conventional indicators. Techniques forprospectively estimating the travelshed of a toll road are compared with the actualtravelshed, as reflected in user home census tracts, as a means of evaluating the efficacyof those techniques in estimating the market area of a prospective toll road.Results show that considering value of time as a percentage of census tractmedian income provides an improved portrayal of the toll road market, as usage of thetoll road increases with increasing income. Using census tract median income as theincome parameter has shortcomings, in that it produces anomalous results at very lowpopulation levels. Of the two methods of estimating the travelshed, the visual estimationapproach was not satisfactory, leaving the analyst to use select link analyses instead.