The sharing economy and the job market: the case of ride-hailing drivers in Chile

Transportation - Ride-hailing (ridesourcing) companies such as Uber, Lyft, and Didi Chuxing have been a disruptive force in the urban mobility landscape around the world during the past decade. In...     

Analysis of child pick-up during daily routines and for daytime no-notice evacuations

In a no-notice disaster (e.g., nuclear explosion, terrorist attack, or hazardous materials release), an evacuation may start immediately after the disaster strikes. When a no-notice evacuation occurs during the daytime, household members are scattered throughout the regional network, and some family members (e.g., children) may need to be picked up. This household pick-up and gathering behavior was seldom investigated in previous work due to insufficient data; this gap in our understanding about who within families handles child-gathering is addressed here. Three hundred fifteen interviews were conducted in the Chicago metropolitan area to ascertain how respondents planned their response to hypothetical no-notice emergency evacuation orders. This paper presents the influencing factors that affect household pick-up and gathering behavior/expectations and the logistic regression models developed to predict the probability that parents pick up a child in three situations: a normal weekday and two hypothetical emergency scenarios. The results showed that both mothers and fathers were more likely to pick up a child under emergency conditions than they were on a normal weekday. For a normal weekday, increasing the distance between parents and children decreased the probability of parents picking up children; in other words, the farther parents are from their children, the less likely they will pick them up. In an emergency, effects of distance on pick-up behavior were significant for women, but not significant for men; that is, increasing the distance between parents and children decreased the probability that mothers pick up a child, but had a less significant effect on the fathers’ probability. Another significant factor affecting child pick-up behavior/expectations was household income when controlling for distance. The results of this study confirm that parents expect to gather children under emergency conditions, which needs to be accounted for in evacuation planning; failure to do so could cause difficulties in executing the pick-ups, lead to considerable queuing and rerouting, and extend the time citizens are exposed to high levels of risk.     

Travel mode choice and travel satisfaction: bridging the gap between decision utility and experienced utility

Over the past decades research on travel mode choice has evolved from work that is informed by utility theory, examining the effects of objective determinants, to studies incorporating more subjective variables such as habits and attitudes. Recently, the way people perceive their travel has been analyzed with transportation-oriented scales of subjective well-being, and particularly the satisfaction with travel scale. However, studies analyzing the link between travel mode choice (i.e., decision utility) and travel satisfaction (i.e., experienced utility) are limited. In this paper we will focus on the relation between mode choice and travel satisfaction for leisure trips (with travel-related attitudes and the built environment as explanatory variables) of study participants in urban and suburban neighborhoods in the city of Ghent, Belgium. It is shown that the built environment and travel-related attitudes—both important explanatory variables of travel mode choice—and mode choice itself affect travel satisfaction. Public transit users perceive their travel most negatively, while active travel results in the highest levels of travel satisfaction. Surprisingly, suburban dwellers perceive their travel more positively than urban dwellers, for all travel modes.     

道路运输--亚欧之桥

9月25日至27日北京举行的"第三届欧亚道路运输大会"是中国举办的首次国际大型交通运输会议.     

Substitution and complementarity patterns between traditional transport means and car sharing: a person and trip level analysis

Transportation - Car sharing is a new transport mode which combines characteristics of private and collective traditional transport means. Understanding the relationship of this mode with existing...     

Revisiting the relationship between traffic congestion and the economy: a longitudinal examination of U.S. metropolitan areas

Conventional transportation practices typically focus on alleviating traffic congestion affecting motorists during peak travel periods. One of the underlying assumptions is that traffic congestion, particularly during these peak periods, is harmful to a region’s economy. This paper seeks to answer a seemingly straightforward question: is the fear of the negative economic effects of traffic congestion justified, or is congestion merely a nuisance with little economic impact? This research analyzed 30 years of data for 89 US metropolitan statistical areas (MSAs) to evaluate the economic impacts of traffic congestion at the regional level. Employing a two-stage, least squares panel regression model, we controlled for endogeneity using instrumental variables and assessed the association between traffic congestion and per capita gross domestic product (GDP) as well as between traffic congestion and job growth for an 11-year time period. We then investigated the relationship between traffic congestion and per capita income for those same 11 years as well as for the thirty-year time period (1982–2011) when traffic congestion data were available. Controlling for the key variables found to be significant in the existing literature, our results suggest that the potential negative impact of traffic congestion on the economy does not deserve the attention it receives. Economic productivity is not significantly negatively impacted by high levels of traffic congestion. In fact, the results suggest a positive association between traffic congestion and per capita GDP as well as between traffic congestion and job growth at the MSA level. There was a statistically insignificant effect on per capita income. There may be valid reasons to continue the fight against congestion, but the idea that congestion will stifle the economy does not appear to be one of them.

     

Revenue sharing with multiple airlines and airports

This paper investigates the effects of concession revenue sharing between an airport and its airlines. It is found that the degree of revenue sharing will be affected by how airlines’ services are related to each other (complements, independent, or substitutes). In particular, when carriers provide strongly substitutable services to each other, the airport has incentive to charge airlines, rather than to pay airlines, a share of concession revenue. In these situations, while revenue sharing improves profit, it reduces social welfare. It is further found that airport competition results in a higher degree of revenue sharing than would be had in the case of single airports. The airport–airline chains may nevertheless derive lower profits through the revenue-sharing rivalry, and the situation is similar to a Prisoners’ Dilemma. As the chains move further away from their joint profit maximum, welfare rises beyond the level achievable by single airports. The (equilibrium) revenue-sharing proportion at an airport is also shown to decrease in the number of its carriers, and to increase in the number of carriers at competing airports. Finally, the effects of a ‘pure’ sharing contract are compared to those of the two-part sharing contract. It is found that whether an airport is subject to competition is critical to the welfare consequences of alternative revenue sharing arrangements.     

长联无缝桥梁成套技术在广西那角中桥的应用

修建全无缝桥梁可以彻底解决桥梁伸缩装置问题。那角中桥是广西第一座应用长联无缝桥梁成套技术的半整体式全无缝桥梁。文章通过介绍那角中桥设计与运营情况,分析了长联无缝桥梁成套技术应用所带来的经济与社会效益,为该技术的推广应用提供依据。     

Effects of built environment and weather on bike sharing demand: a station level analysis of commercial bike sharing in Toronto

Bike Share Toronto is Canada’s second largest public bike share system. It provides a unique case study as it is one of the few bike share programs located in a relatively cold North American setting, yet operates throughout the entire year. Using year-round historical trip data, this study analyzes the factors affecting Toronto’s bike share ridership. A comprehensive spatial analysis provides meaningful insights on the influences of socio-demographic attributes, land use and built environment, as well as different weather measures on bike share ridership. Empirical models also reveal significant effects of road network configuration (intersection density and spatial dispersion of stations) on bike sharing demands. The effect of bike infrastructure (bike lane, paths etc.) is also found to be crucial in increasing bike sharing demand. Temporal changes in bike share trip making behavior were also investigated using a multilevel framework. The study reveals a significant correlation between temperature, land use and bike share trip activity. The findings of the paper can be translated to guidelines with the aim of increasing bike share activity in urban centers.     

加快发展道路运输民营经济

国有经济的战略性调整和国有企业战略性改组,以及交通部结构调整的要求,为民营运输经济的发展带来了机遇.现有的运输市场主体,特别是客运企业,大多为国有专业运输企业,政企不分,行业保护与垄断较普遍.形势的发展呼唤从培育合格的市场主体入手来培育、规范运输市场,大力发展民营经济,从源头上营造行业的公平竞争环境,提高整体竞争力、服务质量和文明程度,建立统一、开放、竞争、有序的道路运输市场体系.     

Maximum acceptable gap between urban-guided transport vehicles and platforms for persons with disabilities: the findings of an experimental study conducted to inform policy decisions

The French ministry responsible for transport has commissioned a study aimed at providing data to determine the maximum gap size between vehicle and platform for guided transport vehicles, which would become a legal requirement. Specific experimental conditions were created, with a physical mock-up simulating a tramway and a platform and providing several gap configurations (between 20 and 50?mm for the horizontal gap and between 20 and 75?mm for the vertical step), and an experimental design based on the negotiation of gaps by wheelchairs users (mainly manual or electric powered). The experiment was conducted with 46 participants with different functional abilities. Data were collected on performance and gap negotiation time. The results of this study indicate that despite the failures observed for the 50?×?50?mm gap size during the experiment, most wheelchair users who took part in the test have successfully negotiated this gap.     

A model to assess cost and fuel savings from ride sharing

A model based on geometric probability concepts is developed to assess the performance of carpooling and vanpooling strategies. Fuel consumption and operating cost issues are treated in the paper, and the model can be extended to treat travel time and air quality issues also. It is shown that simple calculations of the fuel saved through carpool programs can overstate the savings by a factor of two. The operating costs of vanpools and carpools are also compared.     

Recent advances in automotive technology and the cost-effectiveness of fuel economy improvement

The potential for improving the fuel economy of conventional, gasoline-powered automobiles through optimized application of recent technology advances is analyzed. Results are presented at three levels of technical certainty, ranging from technologies already in use to technologies facing technical constraints (such as emissions control problems) which might inhibit widespread use. A fleet-aggregate, engineering-economic analysis is used to estimate a range of U.S. new car fleet average fuel economy levels achievable given roughly 10 years of lead time. Technology cost estimates are compared to fuel savings in order to determine likely cost-effective levels of fuel economy, which are found to range from 39 miles per gallon to 51 miles per gallon depending on technology certainty level. The corresponding estimated increases in average new car price range from $540 to $790 (1993$). Estimated fuel savings payback times average less than 3 years and the cost of conserved energy averages $0.50 per gallon, indicating that these levels of fuel economy improvement are cost-effective over a vehicle lifetime. A vehicle stock turnover model is used to project the reductions in gasoline consumption and associated emissions that would follow if the estimated fuel economy levels are achieved. Potential trade-offs regarding vehicle performance, safety, and emissions are also discussed.     

Circumventing the weight-versus-footprint tradeoffs in vehicle fuel economy regulation

China, Japan, and the European Union use weight-based fuel economy standards, whereas the US Department of Transportation favors footprint-based standards. In this paper we offer a way of reconciling these approaches. Weight-based standards tend to focus regulatory incentives on technology rather than downsizing, but they provide no incentive for weight reduction. Footprint-based standards, by contrast, motivate vehicle manufacturers to reduce weight without reducing footprint, but only to the extent that they are also motivated to increase footprint without increasing weight. Neither approach discriminates between beneficial and detrimental weight-changing strategies. However, the tradeoffs between weight and footprint can be circumvented by employing a weight-based standard, which does not create weight-changing incentives, in combination with complementary regulatory measures that would be focused specifically and exclusively on motivating beneficial weight reduction strategies.     

经济增长刺激公路货运需求

我国经济未来增长将带动公路货运需求的长期快速增长 经济增长是交通运输需求增加和交通发展的基本拉动力.交通运输的增长又是推动经济增长的基础性动力.一般来说,当交通运输的增长滞后于经济增长时,交通运输会成为经济增长的"瓶颈",制约经济增长;当交通运输的增长超前于经济增长时,会带动经济增长,但容易导致交通运输能力的闲置.     

Estimation of gap acceptance parameters within and across the population from direct roadside observation

This paper explores the feasibility of maximum likelihood as an approach to determine the parameters of gap acceptance functions when these functions vary from individual to individual. Specifically, it is shown that it is theoretically possible to estimate the average critical gap of a population of drivers (or pedestrians) and its variance, within and across individuals, from direct roadside observations. Although the Multinomial Probit Model provides a natural theoretical framework for the estimation of these parameters, the model seems not to be statistically estimable for this particular problem. It was shown, however, that if one of the parameters is known, the other two become estimable and a two-stage estimation process that takes into account this phenomenon can be utilized. The technique is demonstrated with the 203-driver data set included in Appendix A. The Multinomial Probit Model can also be used to determine simultaneously the mean critical gap, the mean critical lag (the first gap considered by a driver), and the variances of these. For the data set in Appendix A, the mean critical gap was significantly smaller than the mean critical lag, as one might expect. The techniques proposed in this paper have the further advantage of being statistically efficient with large data sets and of not requiring a panel of individuals to be observed under controlled conditions.     

Increased productivity efforts yield few rewards in the knowledge economy

Population aging is reducing access to knowledge workers even as they are becoming more important to economic growth. Thus far, corporations and governments alike have made the intuitive yet untested assumption that working the existing workforce harder and longer can alleviate the economic fallout. This is based on the ‘success’ similar efforts have previously seen in production industries characterized by physical inputs. Our study provides evidence that these successes may not carry over to industries, such as transportation that are reliant on intellectual skill. It is shown that meeting productivity goals by increasing the job demands of knowledge workers, specifically air traffic controllers, compromises the provision of new kinds of value added. Furthermore, it is demonstrated for the first time that increasing job duration exacerbates the effects of job demand on human performance. Coping with staffing shortages by asking that knowledge workers simply ‘do more’ may impede rather than stimulate economic growth.     

Vehicle attribute trade-offs to meet the 2025 CAFE fuel economy target

The literature analyzes changes in vehicle attributes that can improve fuel economy to meet Corporate Average Fuel Economy (CAFE) standards. However, these analyses exclude either vehicle price, size, acceleration or technology advancement. A more comprehensive examination of the trade-offs among these attributes is needed, this case study focuses on technically feasible modifications to a reference 2012 vehicle to meet the 2025 fuel economy target. Scenarios developed to examine uncertainty in technology advancement indicate that expected technology cost reductions over time will be insufficient to offset the costs of additional fuel efficiency technologies that could be used to meet the 2025 fuel economy target while maintaining other vehicle attributes. The mid-price scenario results show the targeted 66% increase in fuel economy from 2012 to 2025 can be achieved with (i) a 10% ($2070) vehicle price increase (lightweight hybrid electric vehicle), (ii) a 31% (2.9 second) increase in the 0–97 km/h (60 mph) acceleration time (smaller engine), or (iii) a 17% (700 L) decrease in interior volume (smaller body) while maintaining other vehicle attributes. These results are consistent with those obtained using methods that generalize the US light-duty vehicle fleet, but are not a forecast of future vehicle attributes because combinations of less perceptible changes to vehicle price, acceleration and size would also be feasible. This study shows there are numerous ways that 2025 fuel economy targets can be met; therefore, the trade-offs quantified provide important insights on the implications of future CAFE standards.