Red-light cameras at intersections: Estimating preferences using a stated choice model

Red-light cameras placed at intersections have the potential to increase safety, but they are often viewed as an invasion of privacy. Preferences for these cameras were explored using a stated choice model that presents key attributes of camera placements. Stated choice models involve careful experimental design, akin to experimental control in laboratory settings. A variety of design approaches were used, settling on a composition of the choice sets people face in the survey. To illustrate the approach, an internet survey was used with a convenience sample containing a high percentage of college students. The results show that while not the case independently, as the number of cameras and fines for violators are simultaneously increased, the preferences for one particular red light cameras program are likely to improve.     

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

This paper examines the variation in the value of travel time savings (VTTS) for travelers with a managed lane (ML) option when taking an ordinary trip versus a trip that is unusual in some way. VTTS estimates vary substantially depending on the urgency of the trip made. At the low end, the mean VTTS for a traveler who wants to make extra stops and still arrive on time is approximately 10% higher than that for an ordinary trip. At the high end, a traveler running late for an appointment shows a mean VTTS that is approximately 300% higher than that for an ordinary trip. These estimates vary widely over the population of travelers. In light of these variations, the value of an uncongested travel alternative (such as MLs) is examined and found to be greatly undervalued if using typical VTTS estimates.     

The value of travel time and reliability-evidence from a stated preference survey and actual usage

This research examined travel behavior of Managed Lane (ML) users to better understand the value travelers place on travel time savings and travel time reliability. We also highlight the importance of survey design techniques. These objectives were accomplished through a stated preference survey of Houston’s Katy Freeway travelers. Three stated choice experiment survey design techniques were tested in this study: Bayesian (D_b) efficient, random level attribute generation, and an adaptive random approach. Mixed logit models were developed from responses using each of those designs. The value of travel time savings (VTTSs) estimates do vary across the design strategies, with the VTTS estimates based on the D_b-efficient design being approximately half the estimates from the other two designs. However, among the three design strategies, the value of travel time reliability (VOR) was only significant in the D_b-efficient design.The estimated VTTS from actual Katy Freeway usage (as measured using actual tolls paid and travel time saved on the managed lanes) is $51/h. This likely also includes any value that travelers place on travel time reliability. In comparison, our combined estimate of VTTS and VOR based on the SP survey (D_b-efficient design) was $50/h, which is remarkably close to the estimate from the actual usage data. Based on our dataset, the D_b-efficient design technique proved superior to the other two techniques. Finally, this research also supports the importance of including both travel time and travel time reliability parameters when estimating the willingness to pay for, and therefore benefits derived from, ML travel.     

只是开始——汉密尔顿专访

比赛才刚刚开始，最多也是热身结束开始了真正的较量。所以一时的失利大可不必听风就是雨，我的赛车是什么水平自己心里最清楚了。     

Nonlinear Dynamics of Vehicle Traction

Summary The purpose of this study is to understand the nonlinear dynamics of longitudinal ground vehicle traction. Specifically, single-wheel models of rubber-tired automobiles under straight-ahead braking and acceleration conditions are investigated in detail. Customarily, the forward vehicle speed and the rotational rate of the tire/wheel are taken as dynamic states. This paper motivates an alternative formulation in which wheel slip, a dimensionless measure of the difference between the vehicle speed and the circumferential speed of the tire relative to the wheel center, replaces the angular velocity of the tire/wheel as a dynamic state. This formulation offers new insight into the dynamic behavior of vehicle traction. The unique features of the modeling approach allow one to capture the full range of dynamic responses of the single-wheel traction models in a relatively simple geometric manner. The models developed here may also be useful for developing and implementing anti-lock brake and traction control control schemes.     

What drives the gap? Applying the Blinder–Oaxaca decomposition method to examine generational differences in transportation-related attitudes

Transportation - Considerable recent work suggests that Millennials’ behaviors may be converging with those of Generation X as they enter later life stages, but few have investigated whether...     

Who doesn’t mind waiting? Examining the relationships between waiting attitudes and person- and travel-related attributes

Transportation - Waiting, whether for services, for someone, or for something, is an inescapable part of life. This paper addresses a gap in the waiting time literature by examining previously...     

Competition in the UK passenger railway industry: Prospects and problems

The promotion of competition between passenger train operators was a key aim of the 1992- 97 Conservative Government when it privatized British Rail. Although the potential for competition in the market was constrained through regulation at the time of the sale, competition for the market became intense. Regulatory controls are now being relaxed and the promotion of competition remains central to the present Labour Government's rail strategy, particularly in the form of a redefined and reinvigorated franchising programme. It seems to be generally accepted in policy-making circles that it is both possible and desirable to encourage competition in the UK's railway industry on the grounds that it can further enhance service quality across the network. This paper highlights some qualifications to this position and suggests that, for various reasons, a strong policy emphasis on market liberalization may be impractical or unsuitable, at least in the short to medium term.     

Acceptability of Beijing congestion charging from a business perspective

Transportation - Beijing is China’s national capital, a major economic center, and home to nearly 22 million people. The city currently suffers from serious traffic congestion and extreme air...     

Preliminary parametric estimation of steel weight for new ships

This paper presents an agile method for accurately estimating the steel weight of a new ship in the preliminary design stage. A container ship database within a three-dimensional computer-aided design system was used to facilitate the division of a ship into several estimated structural sections, including the forward, cargo, engine room, aft, etc. This procedure is an improvement over the traditional parametric estimation process, which only estimates a rough weight for an entire ship based on specific empirical formulas and then assigns a weight to each part of the ship manually. To estimate the steel weight of a new ship, the parameters of the individual sections are referenced from a similar vessel automatically selected using the principal dimension. Next, principal component analysis is applied to define the principal parameters, i.e., the principal dimension, the feature of each section and the fitting coefficient of the principal parameters. The general equations with the highest correlative predictor variables for the individual sections are then obtained by regression. Comparing the estimation variability, the section estimation provides a more accurate steel weight and constitutes a new means of efficiently obtaining the weight distribution to support the various aspects of preliminary design, i.e., the determination of the center of gravity, the design of the ship lines and ship performance evaluation.