Mark Burris

DISCRETE CHOICE MODELS OF TRAVELER PARTICIPATION IN DIFFERENTIAL TIME OF DAY PRICING PROGRAMS

Tolls that vary based on time of day or congestion are gaining attention around the world as a potential travel demand management strategy that can shift peak period travel to off peak periods thereby contributing to peak period congestion relief. However, despite the widespread interest in the concept, there is very little empirical data available on the impacts of variable tolls on traveler choices and disaggregate models that can be used to predict traveler response to variable pricing are few. This paper reports on results from two bridges with differential time of day tolls in the Lee County area of Florida in the United States. Using travel survey data collected at these two bridges, discrete choice models of traveler response to the variable toll rates are estimated. The models indicate that travelers who are retired, have a low income, have flextime at their place of employment, or have a flexible travel schedule are more likely to alter their time of travel with greater frequency due to the variable toll.

Slugging in Houston—casual carpool passenger characteristics

In the last thirty years, determined travelers have developed a new method of travel that offers the benefits of traveling on an HOV lane without forming traditional carpools. Casual carpools (also known as “slugging”) are impromptu carpools formed among strangers in order to meet the occupancy requirements of HOV lanes. In this research, survey respondent data from Houston, Texas were used to evaluate the behavior of casual carpool passengers. At the time of this research, there were approximately 500 daily casual carpool passengers in Houston during the morning peak period. These passengers saved up to 13 minutes of travel time compared to the alternative of driving alone on the main lanes. Statistical models were used to evaluate the socio-economic and commute characteristics that would indicate an increased likelihood of a traveler choosing to casual carpool. The results of the analyses indicated that being on a commute trip, making more trips per week, being between the ages of 25 and 34, and having occupations that were either professional/managerial or administrative/clerical all increased the likelihood of a traveler choosing to casual carpool. Additionally, having a household income between

The toll-price component of travel demand elasticity

25,000 and

Comparison of Radius-Estimating Techniques for Horizontal Curves

35,000 significantly reduced the likelihood of casual carpooling. The research results provided insight into some of the factors that influenced traveler’s decision to casual carpool. It is important to understand the types of travelers that casual carpooled, and the information learned in these analyses can be used to better evaluate HOV and HOT lane use and performance. Casual carpool passengers can comprise a significant portion of HOV/HOT lane person movement and should be considered when investigating HOV or HOT lane implementation.

Examination of Houston's QuickRide Participants by Frequency of QuickRide Usage

The theory of marginal cost pricing maintains that setting the price of travel equal to its marginal social cost will optimize travel demand. This generally en- tails the addition of a toll during congested periods. The size of this congestion toll and its impact on traffic flow is dependent on the toll-price elasticity of travel demand. This is just one component of the elasticity of travel demand, which includes the elasticity of travel demand with respect to the price of gas, tolls, parking fees, maintenance costs, repair costs, the value of travel time, and other readily perceived costs of driving. This paper examines both the toll-price component of elasticity under flat-rate tolls and tolls that vary either by time of day or congestion level. Using empirical evidence it was found that the toll-price component of the elasticity of variable tolls was generally greater than that of flat-rate tolls with both rates comparable to other component elasticities of travel demand.

Long-Run Changes in Driver Behavior Due to Variable Tolls

Techniques to obtain horizontal curve radii were identified and tested in a controlled experimental study. Ten techniques were identified and pilot tested. Eight of those initial 10 were then used to measure 18 horizontal curves on two-lane rural highways in Texas to evaluate fully their accuracy, precision, cost, ease of use, and safety. Statistically, all eight techniques produced equivalent accuracies, but they displayed a wide range in their precision. The costs varied as a function of the number of times each technique would be used in the field, with those techniques with high initial costs becoming more cost-competitive over the long run with many uses. Ease of use was gauged on the basis of the experience gained during this research. Safety was measured on the basis of whether a technique required personnel on the roadway or roadside or whether it allowed personnel to work from an office or inside a vehicle. The recommendations were based on the expected needs of three different groups that use radii information: transportation agencies, accident investigators, and transportation researchers. Within transportation agencies, engineers and planners in the office will probably benefit most from the plan sheet method, whereas field personnel will probably benefit most from using either the advisory speed or a Global Positioning System (GPS) method. Those who estimate only occasionally, such as accident investigators, will benefit most from the compass method. Finally, researchers or others who may have difficulty accessing plan sheets but still require accurate data will benefit from using a GPS.

Willingness to Pay for High-Occupancy Toll Lanes: Empirical Analysis from I-15 and I-394

QuickRide is an innovative project designed to more effectively use the capacity of the high-occupancy-vehicle (HOV) lanes on the Katy (I-10) and Northwest (US-290) freeways in Houston. Under this project, two-person carpools could pay

Variation in the value of travel time savings and its impact on the benefits of managed lanes

2 to use the HOV lanes during the peak period, even though the lanes were normally restricted to vehicles with three or more occupants. This form of HOV lane is typically termed a high-occupancy toll (HOT) lane and can be an effective travel demand management and congestion mitigation tool. However, relatively little is known about drivers who choose to use the HOT lane option. The commute and socioeconomic characteristics of Houstons QuickRide participants are examined by their frequency of QuickRide usage. The study is based on a survey of QuickRide enrollees conducted in March 2003. It was found that QuickRide participation increases with increasing trip length, perceived time savings, and frequency of trips in the travel corridor. Participation decreases with increasing carpool formation times but is generally irresponsive to minor changes in the

Investigating the Impact of Tolls on High-Occupancy-Vehicle Lanes Using Managed Lanes

2 toll. QuickRide is also more likely to be used for commute trips than other trips. Socioeconomic characteristics such as age, household type, and education also have significant effects on QuickRide trip frequency. However, household size, occupation, and hourly wage rate were not good indicators of the frequency of QuickRide usage.

Reaction to the Managed Lane Concept by Various Groups of Travelers

Managing congestion on highways, especially in urban areas, has been a major challenge for transportation planners and researchers. Variable pricing, specifically time-of-day congestion pricing, is one possible method to manage demand and reduce congestion. Because many variable pricing projects are still in the implementation stage, long-run driver responses to variable tolls are largely unknown. Long-run changes are examined in driver behavior in an existing variable pricing project in Lee County, Florida. By using empirical evidence, it was found that over time the relative price elasticity of demand on the Midpoint Memorial Bridge decreased from -0.42 to -0.11 during the early morning discount period. Elasticities have decreased, but to a lesser extent, during late morning and early afternoon discount periods. A discount period volume spreading ratio was developed, and the change in elasticity results was confirmed by using that method of analysis. It was also found that certain characteristics such as frequency of trips, commute trip purpose, full-time employment status, number of people in the household, higher education, and age between 25 and 34 years were all indicators that participants may increase their variable pricing usage over time. Other characteristics, including being retired and having a household income less than