Metin Senbil

The Optimal Duration for a Travel Survey: Empirical Observations

Empirical observations were carried out using a 6-week travel survey, Mobidrive, to probe into the optimal duration problem of a single wave travel survey. The regressions on certain travel elements (i.e., number of daily trips, VKM per day, number of home based trip chains, daily travel time expenditure) suggest that a 2-week survey duration might serve well to represent personal variability in various dimensions. However further analysis conducted by using nonparametric survival analysis points to a longer period as the elapsed time between activity participation does not seem to converge to true values, at least for rare activities such as recreation.

Policy Effects on Decisions Under Uncertain Conditions: Simulation with Mixed Logit Models of Toll Expressway Use

The aim of this study is to assess the effects of incentives, in the form of toll reductions, introduced to entice commuters to use a toll expressway. Two market segments were targeted: everyday users, for whom the intended effect is to reduce peak-hour congestion by spreading entrances to expressways to off-peak hours, and low-frequency users, for whom the intended effect is to increase their expressway use over surface streets or public transit. To evaluate the effectiveness of toll reductions, an experiment was conducted on an expressway in Osaka, Japan, in which participants received a toll reduction at each expressway use. The experiment lasted for 6 weeks with toll discounts offered during the middle 4 weeks according to certain schedules. Data on the participants’ first trips of the day were collected over the 6-week period. Mixed logit models were developed to describe everyday users’ departure time choice and low-frequency users’ route choice, respectively, in accounting for preference heterogeneity across travelers. Simulation analyses were carried out with various policy options. The results underscore the significance of developing policy measures based on users’ time constraints and work-hour arrangements.

Planning of parking places on transportation infrastructure by geographic information techniques

Considering the increased number of vehicles every day, parking supplies should meet parking demands on transportation infrastructure. Irregular construction and excessive population growth in urban areas required re-planning and site selection of parking places. In this study, an analysis algorithm was developed to determine location-based parking demand by using Geographic Information System (GIS) techniques. After calculating parking demand and supply balance, the location-allocation techniques of network analysis were implemented to determine the best locations of parking, depending on parking demand. These processing tools were tested for an urban area. As a result, an innovative data processing method was developed to determine the best locations of car parking.