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Providing guidance and information to drivers to help them make fuel-efficient route choices remains an important and effective strategy in the near term to reduce fuel consumption from the transportation sector. One key component in implementing this strategy is a fuel-consumption estimation model. In this paper, we developed a mesoscopic fuel consumption estimation model that can be implemented into an eco-routing system. Our proposed model presents a framework that utilizes large-scale, real-world driving data, clusters road links by free-flow speed and fits one statistical model for each of cluster. This model includes predicting variables that were rarely or never considered before, such as free-flow speed and number of lanes. We applied the model to a real-world driving data set based on a global positioning system travel survey in the Philadelphia-Camden-Trenton metropolitan area. Results from the statistical analyses indicate that the independent variables we chose influence the fuel consumption rates of vehicles. But the magnitude and direction of the influences are dependent on the type of road links, specifically free-flow speeds of links. A statistical diagnostic is conducted to ensure the validity of the models and results. Although the real-world driving data we used to develop statistical relationships are specific to one region, the framework we developed can be easily adjusted and used to explore the fuel consumption relationship in other regions. [ABSTRACT FROM AUTHOR]

As an important transport tool, taxi plays a significant role to meet travel demand in urban city. Understanding the travel patterns of taxis is important for addressing many urban sustainability challenges. Previous research has primarily focused on examining the statistical properties of taxi trips to characterize travel patterns, while it may be more appropriate to explore taxi service strategies on seasonal, weekly or daily time scale. Therefore, intra-urban taxi mobility is investigated by examining taxi trajectory data that were collected in Harbin, China, while 12-week corresponding to 12-month is chosen as the sampling period in our study. The multivariate spatial point pattern analysis is firstly adopted to characterize and model the spatial dependence, and infer significant positive spatial relationships between the picked up points (PUPs) and the dropped off points (DOPs). Secondly, the points of interest (POIs) are identified from DOPs using the emerging hot spot detection technique, then the taxi services and movement patterns surrounding POIs are further examined in details. Moreover, our study builds on and extends the existing work to examine the statistical regularities of trip distances, and we also validate and quantify the impacts posed by airport trips on the distance distributions. Finally, the movement-based kernel density estimation (MKDE) method is proposed to estimate taxis' service ranges within three isopleth levels (50, 75 and 95%) between summer/weekday and winter/weekend from taxi driver's perspective, and season as well as temperature factors are identified as the significant effect within certain service range levels. These results are expected to enhance current urban mobility research and suggest some interesting avenues for future research. [ABSTRACT FROM AUTHOR]

Copyright of Recherches Sociographiques is the property of Recherches Sociographiques and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

By understanding the implications of real-world driving conditions, improved fuel economy via a strategy of key technologies can be implemented to assist fuel economy validation during development programs. Vehicles in real-world driving conditions regularly travel at idle, low and medium speeds, particularly for urban driving, and this has a crucial weight in overall vehicle fuel economy, given the residencies at the lower engine speed and load region. This paper presents the validation of the derived engine conditions representing Malaysian actual urban driving in an attempt to formulate representative fuel economy data. The measurements were conducted through on-road urban driving within Kuala Lumpur to establish representative driving conditions. The effectiveness of the proposed conditions was then validated in terms of fuel economy using a simulation. The discrepancy between the fuel economy in the proposed conditions and the real-world measurements has improved, falling to 11.9% compared to 43.1% reported by the NEDC. [ABSTRACT FROM AUTHOR]

Traffic congestion caused by either insufficient road capacity or unexpected events has been a major problem in urban transportation networks. To disseminate accurate traveler information and reduce congestion impact, it is desirable to develop an adaptive model to predict travel time. The proposed model is practically implementable to capture dynamic traffic patterns under various conditions, which integrates the features of exponential smoothing and the Kalman filter by utilizing both real-time and historic data. The model is simple in formulation while robust in performance in terms of accuracy and stability. With a constraint or nonconstraint smoothing factor, the proposed model is tested with both real world and simulated data and demonstrated itself a sound model that outperforms others (e.g., Kalman filter and simple exponential smoothing) specifically under recurring and nonrecurring congestion. [ABSTRACT FROM AUTHOR]

The speed range of Levels of Service (LOS) categories is not well defined for highly heterogeneous traffic flow on urban streets in Indian context. Determination of speed ranges of LOS categories of urban traffic facilities helps in planning, design of transportation projects and also allocation of resources among competing projects. In this study an attempt has been made to define LOS criteria for urban street in Indian context considering the free flow speed (FFS), congested travel speed, the geometric and surrounding environmental conditions. Defining LOS criteria is basically a classification problem and cluster analysis is found to be the most suitable technique that can be applied. In this study Clustering Large Applications (CLARA) method is used. Large numbers of speed data are used as an input to CLARA. Using Global Positioning System (GPS) large numbers of second by second speed data are collected and GIS was used in handling large amount of speed data. The clustering algorithm is used twice in this study. The optimal number of clusters is determined using six cluster validation parameters which help in deciding the classification of street segments into numbers of classes. CLARA algorithm was used to classify the FFS data into a number of classes to get the FFS ranges of different urban street classes such that street segments following a class must satisfy its functional and geometric characteristics. In the second stage CLARA algorithm is used on average travel speed data collected during both peak and off-peak hours to determine the speed ranges of different LOS categories. From the above study the FFS ranges for different urban street classes and speed ranges for different LOS categories are defined and the values are found to be lower than that suggested by HCM-2000. Average travel speed of LOS categories expressed in terms of percentage of FFS of the street classes are found to be 85 and above, 70-85, 55-70, 40-55, 30-40, 30 and below respectively for LOS "A" to "F". This result closely follows the percentage shown in HCM-2010. [ABSTRACT FROM AUTHOR]

Abstract: Eighty-five volunteer drivers, 65–85 years old, without cognitive impairments impacting on their driving were examined, in order to investigate driving errors characteristic for older drivers. In addition, any relationships between cognitive off-road and on-road tests results, the latter being the gold standard, were identified. Performance measurements included Trail Making Test (TMT), Nordic Stroke Driver Screening Assessment (NorSDSA), Useful Field of View (UFOV), self-rating driving performance and the two on-road protocols P-Drive and ROA. Some of the older drivers displayed questionable driving behaviour. In total, 21% of the participants failed the on-road assessment. Some of the specific errors were more serious than others. The most common driving errors embraced speed; exceeding the speed limit or not controlling the speed. Correlations with the P-Drive protocol were established for NorSDSA total score (weak), UFOV subtest 2 (weak), and UFOV subtest 3 (moderate). Correlations with the ROA protocol were established for UFOV subtest 2 (weak) and UFOV subtest 3 (weak). P-Drive and self ratings correlated weakly, whereas no correlation between self ratings and the ROA protocol was found. The results suggest that specific problems or errors seen in an older person''s driving can actually be “normal driving behaviours”. [Copyright &y& Elsevier]

Abstract: This communication examines carbon dioxide levels in a small passenger car in city driving. It looks at situations with only a driver and when an adult passenger is on board; in both cases with and without air ventilation on. [Copyright &y& Elsevier]

The peculiarities of constructing a model of an individual vehicle moving along the urban street are investigated. The aim of the study is to construct a dynamic vehicle-environment-driver model, which enables to implement the situation ‘an individual vehicle moving along urban streets’, taking into consideration a concrete type of a vehicle, its loading, driver's behavior, peculiarities of external characteristics of internal combustion engines run on traditional or alternative fuel as well as the use of hybrid power plants. [ABSTRACT FROM PUBLISHER]

Abstract: Road authorities considering the implementation of speed management interventions should have access to the results of scientifically robust evaluations on which to base their decisions. However, studies that evaluate a diverse range of interventions with comparable metrics are rare, with most focussing on one type, for example, types of signage, perceptual countermeasures or physical traffic calming. This paper describes a driving simulator study designed to overcome these constraints. Twenty diverse speed-reducing treatments were developed and tested in urban and rural road environments. Forty participants encountered all the treatments allowing a comparison to be made with their driving behaviour when the treatment was not present. A number of speed parameters were developed to encapsulate the range of effects of the treatments. The results suggest that whilst straight sections of road are difficult to treat, speed reductions can be obtained by increasing risk perception. In contrast, alerting treatments had more effect at junctions, particularly in an urban environment; drivers approaching curves demonstrated improved speed adaptation if the curve radius was highlighted (either implicitly or explicitly). The study highlights how driving simulators can be used to overcome methodological constraints encountered in real-world evaluations of this type. [Copyright &y& Elsevier]

In the last decade, the authorities require the use of safe, comfortable vehicles to assure a door to door aspect with respect of environment in the urban context. In this paper, we propose an advanced approach of transport regulation where we integrate cybercars into a regulation process as an alternative in disruption cases. For that, we propose an ITS architecture including public transportation and cybercars into the same framework. We will show that collaboration between these two systems provides better results than managing them separably. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a new method for assessing the risk of accidents associated with darkness. The method estimates the risk of accident associated with darkness in terms of an odds ratio, which is defined as follows: [(number of accidents in darkness in a given hour of the day)/(number of accidents in daylight in the same hour of the day)]/[(Number of accidents in a given comparison hour when the case hour is dark)/(Number of accidents in a given comparison hour when the case hour is in daylight)]. This estimate of the risk of accident associated with darkness does not require data on exposure, but relies on the count of accidents in the same pair of hours throughout the year. One of the hours is dark part of the year, but has daylight the rest of the year. The comparison hour, which has daylight the whole year, is used to control for seasonal variations. The aim of relying on the same pair of hours throughout the year is to minimise the influence of potentially confounding factors. Estimates of the risk of injury accidents associated with darkness are developed on the basis of accident data for Norway, Sweden and the Netherlands. It is found that the risk of an injury accident increases by nearly 30% in darkness in urban areas, by nearly 50% in rural areas, and by about 40% for urban and rural areas combined (adjusted estimate). [Copyright &y& Elsevier]

Copyright of Recherches Sociographiques is the property of Recherches Sociographiques and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article presents the architecture of Junior, a robotic vehicle capable of navigating urban environments autonomously. In doing so, the vehicle is able to select its own routes, perceive and interact with other traffic, and execute various urban driving skills including lane changes, U-turns, parking, and merging into moving traffic. The vehicle successfully finished and won second place in the DARPA Urban Challenge, a robot competition organized by the U.S. Government. © 2008 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

This paper reports on AnnieWAY, an autonomous vehicle that is capable of driving through urban scenarios and that successfully entered the finals of the 2007 DARPA Urban Challenge competition. After describing the main challenges imposed and the major hardware components, we outline the underlying software structure and focus on selected algorithms. Environmental perception mainly relies on a recent laser scanner that delivers both range and reflectivity measurements. Whereas range measurements are used to provide three-dimensional scene geometry, measuring reflectivity allows for robust lane marker detection. Mission and maneuver planning is conducted using a hierarchical state machine that generates behavior in accordance with California traffic laws. We conclude with a report of the results achieved during the competition. © 2008 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Abstract: Current driving cycles used in China are not able to accurately assess vehicle emissions due to their inadequate representation of real-world driving. We in this study analyzed the driving characteristics and developed the driving cycles in Chinese cities, then compared them to the European test cycle and the American Federal Test Procedure. Eleven cities were selected, covering different city sizes and geographical locations. Car chasing technique was employed in each city to collect speed–time data on freeways, arterials, and residential roads during traffic peak and non-peak periods. The data collected were adjusted by the traffic adjustment factors to reflect the overall traffic. Eleven driving parameters were used to characterize driving characteristics and develop driving cycles. The results indicate that city size, local road infrastructure, and driving behavior are the most important factors that lead to the significant differences in vehicle driving patterns among the cities. The comparison with the European and US cycles suggests that the emission factors produced from the European or US cycles-based tests could be significantly different than those from the driving cycles in China. [Copyright &y& Elsevier]

This article discusses the potential impact of increased urban density on the prevention of global warming. The author notes that the number of miles driven in the U.S. has outpaced the growth in population. The author suggests that redesigning cities can reduce the need for automobile use and consequently reduce greenhouse gas emissions. The author reviews the literature on the relationship between greenhouse gas emissions and urban form. The author presents three scenarios that contrast the effects of urban infill with urban sprawl, indicating that infill could potentially benefit the environment.

An instrumented EURO I Ford Mondeo was used to perform a real-world comparison of vehicle exhaust (carbon dioxide, carbon monoxide, hydrocarbons and oxides of nitrogen) emissions and fuel consumption for diesel and 5% biodiesel in diesel blend (B5) fuels. Data were collected on multiple replicates of three standardised on-road journeys: (1) a simple urban route; (2) a combined urban/inter-urban route; and, (3) an urban route subject to significant traffic management. At the total journey measurement level, data collected here indicate that replacing diesel with a B5 substitute could result in significant increases in both NO x emissions (8–13%) and fuel consumption (7–8%). However, statistical analysis of probe vehicle data demonstrated the limitations of comparisons based on such total journey measurements, i.e., methods analogous to those used in conventional dynamometer/drive cycle fuel comparison studies. Here, methods based on the comparison of speed/acceleration emissions and fuel consumption maps are presented. Significant variations across the speed/acceleration surface indicated that direct emission and fuel consumption impacts were highly dependent on the journey/drive cycle employed. The emission and fuel consumption maps were used both as descriptive tools to characterise impacts and predictive tools to estimate journey-specific emission and fuel consumption effects. [Copyright &y& Elsevier]

In urban transportation planning, it has become critical (1) to determine the travel time of a traveler and how it is affected by congestion, and (2) to understand how traffic distributes in a transportation network. In the first part of this paper, we derive an analytical function of travel time, based on the theory of kinematic waves. This travel-time function integrates the traffic dynamics as well as the effects of shocks. Numerical examples demonstrate the quality of the analytical function, in comparison with simulated travel times. In the second part of this paper, we incorporate the travel-time model within a dynamic user equilibrium (DUE) setting. We prove that the travel-time function is continuous and strictly monotone if the flow varies smoothly. We illustrate how the model applies to solve a large network assignment problem through a numerical example. [ABSTRACT FROM AUTHOR]

We study the effect of inter-vehicle communications and use simple models and simulations to evaluate various scenarios. Both highway systems and urban city driving cases are considered. Adaptive cruise control (ACC) and merging/lane changing scenarios are studied for highway systems. Stop-and-go operation and intersection safety are considered for in-city applications. A simple human driver model is used to represent the reactions of the drivers. A specially developed traffic simulator is utilised to simulate the proposed scenarios for various traffic flows. [ABSTRACT FROM AUTHOR]

Abstract: Although previous research has supported the view that neo-traditional or new urbanist designs result in more walking activity, several questions remain: Do residents of these neighborhoods substitute walking for driving trips, or do they make more trips overall? What is the role of self-selection of residents in these developments? This paper aims to address these questions by examining differences in travel behavior in a matched pair of neighborhoods (one conventional and one neo-traditional) in Chapel Hill and Carrboro, North Carolina. A detailed behavioral survey of 453 households and two-stage regression models suggest that single-family households in the neo-traditional development make a similar number of total trips, but significantly fewer automobile trips and fewer external trips, and they travel fewer miles, than households in the conventional neighborhood, even after controlling for demographic characteristics of the households and for resident self-selection. The findings suggest that households in the neo-traditional development substitute driving trips with walking trips. [Copyright &y& Elsevier]

A procedure is presented for evaluating the performance in terms of driving style of public transport bus drivers, within the context of a programme for energy savings in urban public transportation. The purpose of this evaluation is that of providing suitable tools for training of personnel with the objective of attaining more energy-efficient driving styles and improving driving quality. Quality can be defined as the combination of an energy saving driving style with a behaviour that is respectful of the environment (noise, pollution and safety) and of the vehicle and is comfortable for the passengers as well. Economical driving provides direct savings in fuel of up to 25 per cent as well as indirect savings deriving from general improvements in quality; a more controlled driving style can also be accompanied by reductions in air pollution and noise emission. The procedure utilizes a fuzzy logic approach and can be implemented aboard vehicles in an automatic monitoring system, the sole requirement being that of measuring the instantaneous road speed of the vehicle and its current load. The procedure has been developed and validated on the basis of data coming from a test campaign carried out on vehicles equipped with automatic and manual transmission, operating over both urban and intercity itineraries in three different cities, and adopting different driving styles with different drivers. By analysing the results, in relation to the itinerary and conditions of traffic, stops, load, etc., it can be determined which conditions, for each driver, lead to either good or poor performance. Such specific information, together with assessment of the overall driving style, provides useful indications for training drivers, both through training programmes with specific itineraries and trials, and through self-learning processes with the procedure implemented using an on-board monitoring system. [ABSTRACT FROM AUTHOR]

This paper presents a parametric study of the energy demands of car transportation on two competing inter-city commuter routes in the UK for all main categories of automotive vehicles. The commuter routes are between Bristol and Bath: one is fast and flat, the other is relatively hilly and with tighter speed restrictions. Energy demands were found to be closely related to the vehicle mass because almost all external forces on the car are either directly or indirectly influenced by the mass of the vehicle. Exposure to the wind was found to be an important parameter that can significantly affect fuel consumption. Reducing vehicle mass is an important way of improving the performance of the car. However, there are limits to what can be achieved in weight reduction because of safety requirements and the desire of car owners to have many luxury items in modern cars. The official European fuel consumption and emissions test is limited in the extent to which it measures parameters that affect fuel consumption. For example, the test does not measure the frontal area or drag coefficient of the car. The design of the route and traffic operation can have a very significant influence on the efficiency of car transportation and therefore it is necessary to consider route design in whole-life analysis. [Copyright &y& Elsevier]

Identifies the factors that cause driving-induced stress in urban college students. Traffic congestion; Road construction; Search for parking place; Slow drivers; Vehicle following too closely; Percentage of subjects who had reported another driver to a policeman.

Presents a study on the red-light running behavior of drivers in Southeast Virginia. Consideration of red-light running as a dangerous driving act; Factors for predicting red-light runners; Correlation between higher traffic volume and higher red-light turning rate; Importance of observations in improving intersection safety.

Driving in cast impairs driving ability. We surveyed driving behaviour of orthopaedic trauma patients. Fifteen percent admitted that they drove while in cast. In a national context, this would mean that over 500 people drive every year on Irish roads while still wearing a forearm or below knee cast. In reality, this is probably a gross underestimation. [ABSTRACT FROM AUTHOR]

Studies the psychological aspects of left turning traffic procrastinators in city driving. Tendency of drivers to move out more slowly when someone is waiting behind them; Gende, demographic and other characteristics of the said drivers.

This paper discusses a new prototype engine that is claimed to greatly improve fuel economy particularly urban driving is presented in this paper. The technology comes under the unlikely acronym Music, which stands for Merritt unthrottled spark ignition combustion, an engine developed by Dr. Dan Merritt of Coventry University. By adopting diesel engine processes and incorporating them into a petrol engine, Merritt and his team say they have achieved a 20 per cent gain in efficiency, as well as a significant reduction in carbon and nitrogen emissions. A diesel engine is more efficient than a petrol one because it sprays tiny droplets of fuel into very hot air. Diesel fuel will ignite on contact with the heat. A petrol engine has to create a correct mix of air and fuel, which is less efficient. [ABSTRACT FROM AUTHOR]

The article offers information on three techniques that are available to drivers to initiate a change in a vehicle's path of travel (POT) while in a turn. Adjusting vehicle direction mid-turn increases the number of options for a driver. While turning the wheel is the sole way to initiate a turn from the straight-ahead position, there are at least three ways to adjust a vehicle's direction once in a turn. The most common way is to use the steering wheel. A second way to adjust POT while in a turn is to brake slightly. A third way to adjust POT while turning is to accelerate. This action is not performed to increase the vehicle's speed, but rather to shift the vehicle's weight rearward.