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1.
This paper analyzes the effects of cell phone usage and economic freedom on motor vehicle death rates by estimating regression models on data for three years across 38 countries. The models incorporate a representative set of motor vehicle fatality determinants. Results indicate that cell phone use has a statistically significant nonlinear impact on highway death rates and that economic freedom does not appear to have an effect.  相似文献   

2.
This paper examines the impact of cell phone usage on pedestrian fatalities in the United States using econometric models and specification error tests. The model makes use of a polynomial specification so as to allow for potential life-saving and life-taking effects of cell phones. The results indicate that when cell phones were first introduced they had an adverse effect on pedestrian safety, but after a critical number of cell phones was reached, the life-saving effect dominated over the life-taking effect. However, as the number of phones continued to increase, the life-taking effect once again dominated over the life-saving effects.  相似文献   

3.
This paper develops a GIS-based Bayesian approach for intra-city motor vehicle crash analysis. Five-year crash data for Harris County (primarily the City of Houston), Texas are analyzed using a geographic information system (GIS), and spatial–temporal patterns of relative crash risks are identified based on a Bayesian approach. This approach is used to identify and rank roadway segments with potentially high risks for crashes so that preventive actions can be taken to reduce the risks in these segments. Results demonstrate the approach is useful in estimating the relative crash risks, eliminating the instability of estimates while maintaining overall safety trends. The 3-D posterior risk maps show risky roadway segments where safety improvements need to be implemented. Results of GIS-based Bayesian mapping are also useful for travelers to choose relatively safer routes.  相似文献   

4.
This paper analyzes the influence of highway safety regulation enforcement efforts on motor vehicle fatalities. It estimates a regression model in which such deaths depend on these efforts as well as economic conditions, driver characteristics, government regulations, and locational factors, using 1973–2000 annual Ohio data. Statistically significant results indicate that the enforcement measure of drunk driving arrests saves lives. They also suggest that highway deaths increase with the following: better economic conditions, greater alcohol consumption, larger proportions of young and old drivers, higher speed limits, and more driving on rural roads. The trend in deaths is downward.  相似文献   

5.
6.
This paper introduces a new approach for explaining the effects of spatial competition for opportunities based on a cumulative opportunities measure of accessibility. We focus on the case of the labor market where some municipalities offer too few workplaces for their local population, forcing some of their residents to long drives. We apply this new accessibility measure to explain households' annual mileage in Switzerland using a Heckman model to account for carless households.We find that car travel demand is much greater in municipalities with a relative undersupply in the local labor market compared to a balanced or oversupplied local labor market. The results show that driving increases with greater distance to the labor market center. The model estimates allow policy makers and planners to quantify as a first assessment the expected average mileage in each municipality for new settlements and to identify municipalities with low expected annual mileage.  相似文献   

7.
This paper analyzes the impacts of the built environment (BE) as it relates to the potential job accessibility (PJA) effects of road pricing. The relationships between the BE elements and PJA under a road charging policy are established using a spatial econometric approach, which uses an integrated land use and transportation model (TRANUS model) and a spatial lag model (SLM). With the intent of further analyzing the differences in the PJA effects of road pricing on traffic analysis zones (TAZs) that contain different combinations of BE elements, a quantitative classification method combining factor and cluster analysis is applied. This will quantitatively categorize TAZs inside and outside the tolled areas. In exploring the relationship between changes in PJA and the road pricing policy, we found the spatial autocorrelation coefficient to be negative. This result suggests that we are unable to increase the PJA of all the regions through road pricing, but rather affect a redistribution of PJA between different regions. Results also indicate that the impacts of road charging on PJA are associated with urban BE elements. Moreover, such effects are the common result of specific characteristics of the BE. The higher the number of jobs, the better the public transportation conditions, and the better the street design (high densities of street and intersections), the less the region will be negatively influenced by a road charging policy, and vice versa. To avoid the negative effects of road pricing on PJA prior to the launch of such a policy, cities should improve public transportation networks and enhance the street design of the road pricing policy areas, especially the toll ring periphery area.  相似文献   

8.
A number of transportation infrastructure projects were conducted in Europe during the 1990s with the explicit objective of promoting regional cohesion goals through the improvement of the accessibility of peripheral regions. Given its peripheral situation in the Union, Portugal was a key target for some of these projects. A decade later, it is pertinent to ask whether the new infrastructure achieved its objective of promoting lagging regions. The objective of this paper is to analyze one of the lagging regions in Portugal, to try to establish the link between changes in accessibility levels brought by improvements in the transportation network, and two indicators commonly used in accessibility research (population and purchasing power), while controlling other variables of possible relevance, such as the levels of educational achievement of the population in the region. The analysis is based on the use of spatially autoregressive models which allow the representation of accessibility as spatially lagged variables of first and second order. The results place the contribution of accessibility changes in context, and point at the relevance of education as an alternative policy.  相似文献   

9.
An econometric model of the barge and rail freight market is developed so that factors which influence barge and rail rates for export-bound grain from Midwest to Mexican Gulf can be better understood. Three-stage least squares method is used to estimate the system of four equations that constitute the model. A number of identified factors turned out to be significant in determining grains rail and barge transportation rates. Given the interactive nature of supply and demand processes it is difficult to pinpoint a single most important factor. Yet it is clear that a substitute nature of the two transportation modes in addition to direct price-quantity relationship determine most of the transportation rates.  相似文献   

10.
Analytical modeling and insights, numerical experiments, and real-world tour data are used to understand the impact of congestion on urban tour characteristics, carriers’ costs, and distance/time traveled. This paper categorizes tours into three classes based on their tour efficiency and variable costs structure. Travel time/distance between customers and depot is found to be a crucial factor that exacerbates the negative impacts of congestion. Travel time variability is a significant factor only when travel time between depot and customers is considerable in relation to the maximum tour duration. For each customer, it is possible to define a dimensionless coefficient that provides an indication of the relative impact of congestion on routing constraints. Congestion also affects carriers’ cost structure, as congestion worsens the relative weight of wages and overtime escalates and the relative weight of distance related costs decrease.  相似文献   

11.
Regression models are employed to quantify the effects of vehicle restrictions on private and public transport passenger flows in Santiago, Chile using trip flow data for cars, buses and the city's Metro rail system. Estimates are derived for the effects of two restrictions: a permanent measure applied from April through August 2008 to vehicles without catalytic converters and additional measures that banned the use of vehicles with catalytic converters between 7:30 am and 9 pm on days declared as environmental “pre-emergencies” due to high air pollution levels. The estimates show that the permanent restriction had no impact on the use of private cars while the additional restriction curtailed their use by 5.5%. Also, on pre-emergency days the flow of passengers to the Metro increased by about 3% while the bus network showed no statistically significant increase. The pre-emergency restrictions thus had an effect on the ridership of the Metro but not on the bus network as alternatives to the use of private cars.  相似文献   

12.
We propose a model for freight rate formation in individual contracts that incorporates charterer and owner heterogeneity and owner–charterer match effects. We estimate fixed effect regressions and implement a variance decomposition for 2863 VLCC tanker and 1789 Capesize fixtures between 2011 and 2014. Although market conditions and routes remain the most influential covariates, the characteristics of charterers, owners and of their matches are also significant microeconomic determinants of the freight rate level. The contribution of the charterer fixed effect is large in the VLCC market, while the charterer and match effects are large contributors to the Capesize spot freight rate.  相似文献   

13.
Many studies have demonstrated that the built environment has a strong impact on people's travel mode choice. However, the built environment also influences elements such as travel distance and car ownership, which might be the true predictors of which travel modes are chosen. In this study, we analyse the effects of changes in residential neighbourhood on changes in travel mode (for commute trips and leisure trips), both directly and indirectly through changes in car ownership, travel distances and travel attitudes. This study applies a structural equation modelling approach using quasi-longitudinal data from 1650 recently relocated residents in the city of Ghent, Belgium. Results indicate that the built environment has strong direct effects on active leisure trips and car use. However, distance (for car use) and attitudes (for active travel) were found to be important mediating variables. In sum, the effect of the built environment on travel mode choice might be more complex than commonly assumed as it partly seems mediated by travel distance and travel attitudes.  相似文献   

14.
In this paper, the provision of bus services along different routes that comprise a public transit network is assessed taking into consideration, the service providers, the users and the societal perspectives. This model is based on Data Envelopment Analysis (DEA) [Charnes, A., Cooper W.W., Rhodes, E., 1978. Measuring the efficiency of decision-making units. European Journal of Operational Research 2, 429–444] and derives from the Network Model in DEA [Färe, R., Grosskopf, S., 2000. Network DEA. Socio-Economic Planning Sciences 34, 35–49] and Goal Programming in DEA [Athanassopoulos, A., 1995. Goal programming and data envelopment analysis (GoDEA) for target-based multi-level planning: allocating central grants to the Greek local authorities. European Journal of Operational Research 87, 535–550]. This proposed approach enables the decision maker not only to optimally allocate resources across the transit network but to achieve targets for societal variables that represent the environment in which the bus services are provided.  相似文献   

15.
Increasing the share of battery electric vehicles (BEV) in the total car fleet is regarded as a promising way to reduce local car emissions. Based on online surveys in Denmark and Sweden, this study compares BEV users' (n = 673) and conventional vehicle (CV) users' (n = 1794) socio-demographic profiles, attitudinal profiles, and mobility patterns. In line with previous research, BEV users are typically male, highly educated, have high incomes, and often more than one car in their household. Additionally, BEV users perceive less functional barriers toward BEV use and have more positive attitudes and norms than CV users. The different profiles of these user groups suggest a separate analysis of potential factors of BEV adoption in both groups. In regression analyses, CV and BEV users' intention to use/purchase a BEV is modeled based on factors of the Theory of Planned Behavior extended by personal norm, perceived mobility necessities, and BEV experience. For CV users, symbolic attitudes related to BEVs are the most important factor of intention, while perceived functional barriers in terms of driving range are most relevant for BEV users' intention. How BEV users cope with trips of longer distance seems of particular relevance. In multiple car households, we found the percentage of actual BEV usage related to the type of other cars in the household, perceived functional barriers of BEVs as well as (successful) behavioral adaption to longer trips by BEVs. Based on the results, we discuss ways to increase BEV adoption for current users and non-users.  相似文献   

16.
Crosswalks located at mid-block segment between roundabouts can provide a good balance among delay, carbon dioxide (CO2) emissions, and relative difference between vehicles and pedestrians speed. However, when considering local pollutant criteria, the optimal crosswalk location may be different to that obtained for CO2. This paper described a multi-objective analysis of pedestrian crosswalk locations, with the objectives of minimizing delay, emissions, and relative difference between vehicles and pedestrians speed. Accounting for the difference between global (e.g., CO2) and local pollutants (monoxide carbon, nitrogen oxides, and hydrocarbons) was one the main considerations of this work. Vehicle activity along with traffic and pedestrian flows data at six roundabout corridors in Portugal, one in Spain, and one in the United States were collected and extracted. A simulation environment using VISSIM, Vehicle Specific Power, and Surrogate Safety Assessment Model models was used to evaluate traffic operations along the sites. The Fast Non-Dominated Sorting Genetic Algorithm (NSGA-II) was implemented to further search optimal crosswalk locations. The results yielded improvements to both delay and emissions by using site-optimized crosswalks. The findings also revealed that the spacing between intersections widely influenced the optimal crosswalk location along a mid-block section. If the spacing is low (<100 m), the crosswalk location will be approximately in 20%–30% of the spacing length. For spacing values between 140 and 200 m, crosswalks would be located at the midway position. When a specific pollutant criterion was considered, no significant differences were observed among optimal crosswalk data sets.  相似文献   

17.
This paper seeks to contribute to ongoing debates around the politics of hybrid mobilities, smart cities, surveillance capitalism and mobility fixing. Based on a set of qualitative interviews with key stakeholders and secondary sources, the paper uses the emergence of dockless public bike sharing in Shanghai between 2016 and 2018 as its case study. In order to explain the emergence of dockless PBSS and illustrate our contention that this system seeks to create surplus value from the work of mobility (in this case cycle commuting), we examine the processes of valorisation that have occurred in order to both position PBSS as a worthy activity (and therefore remunerate participants affectively) and produce use values for the data generated by users. In doing so we also highlight the ways in which these processes of valorisation seek to ensure that the mobility work of users is not aligned with the products of that labour in order to avoid calls for this mobility work to be remunerated as wage labour (which would reduce any surplus value extraction). Ultimately we argue that these processes of valorisation are not only invasive, but exclusionary in that they prioritise select aspects of social practice that address matters of (governmental) concern, rather than a more rounded interpretation. We argue that there is an urgent need to recognise mobility practices beyond registers that simply prepare the ground for their marketisation.  相似文献   

18.
Emerging transportation technologies have the potential to significantly reshape the transportation systems and household vehicle ownership. Key among these transportation technologies are the autonomous vehicles, particularly when introduced in shared vehicle fleets. In this paper, we focus on the potential impact that fleets of shared autonomous vehicles might have on household vehicle ownership. To obtain initial insights into this issue, we asked a sample of university personnel and members of the American Automobile Association as to how likely they would consider relinquishing one of their household's personal vehicles if shared autonomous vehicles were available (thus reducing their household vehicle ownership level by one). For single-vehicle households, this would be relinquishing their only vehicle, and for multivehicle households (households owning two or more vehicles) this would be relinquishing just one of their vehicles. Possible responses to the question about relinquishing a household vehicle if shared autonomous vehicles are present are: extremely unlikely, unlikely, unsure, likely, and extremely likely. To determine the factors that influence this response, random parameters ordered probit models are estimated to account for the likelihood that considerable unobserved heterogeneity is likely to be present in the data. The findings show that a wide range of socioeconomic factors affects people's likelihood of vehicle relinquishment in the presence of shared autonomous vehicles. Key among these are gender effects, generational elements, commuting patterns, and respondents' vehicle crash history and experiences. While people's opinions of shared autonomous vehicles are evolving with the continual introduction of new autonomous vehicle technologies and shifting travel behavior, the results of this study provide important initial insights into the likely effects of shared autonomous vehicles on household vehicle ownership.  相似文献   

19.
This paper presents a comparison of attitudes towards congestion and parking tolls and explores their effect on travel behavior. The findings indicate that drivers are sensitive mainly to congestion tolls and are willing to change their travel habits to avoid these tolls. The major effect of a congestion toll is the shifting of the time of the journey. High levels of demand elasticity (−1.8 for congestion tolls and −1.2 for parking fees) were found. The readiness to pay parking fees is greater; thus, the effectiveness of congestion tolls in reducing demand is higher during the times the tolls apply.  相似文献   

20.
This paper examines how alliance co-specialization and scope extension affect firm value at the time of alliance formation and termination, and whether value creation upon alliance formation also explains value creation upon termination. Building on the relational view of the firm, we develop predictions that are tested using event study methodology and data on code-sharing alliances formed, extended, and terminated between 1994 and 2008. The findings suggest that from a stock market perspective alliance formation and termination can be seen as two interrelated events and that it is difficult to reverse initial valuations past the alliance formation phase. They also suggest that the stock market reacts to alliance formation more critically than to post-formation decisions such as alliance scope extensions and terminations.  相似文献   

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