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In a road network with refueling and fast charging stations, the minimum-cost driving path of a plug-in hybrid electric vehicle (PHEV) depends on factors such as location and availability of refueling/fast charging stations, capacity and cost of PHEV batteries, and driver tolerance towards extra mileage or additional stopping. In this paper, our focus is long-distance trips of PHEVs. We analyze the impacts of battery characteristics, often-overlooked driver preferences and road network features on PHEV travel costs for long-distance trips and compare the results with hybrid electric and conventional vehicles. We investigate the significance of these factors and derive critical managerial insights for shaping the future investment decisions about PHEVs and their infrastructure. In particular, ourfindings suggest that with a certain level of deployment of fast charging stations, well established cost and emission benefits of PHEVs for the short range trips can be extended to long distance. Drivers' stopping intolerance may hamper these benefits; however, increasing battery capacity may help overcome the adverse effects of this intolerance. © 2014 Elsevier Ltd.

Although previous studies report on the effect of street washing on ambient particulate matter levels, there is a lack of studies investigating the results of street washing on the emission strength of road dust. A sampling campaign was conducted in Madrid urban area during July 2009 where road dust samples were collected in two sites, namely Reference site (where the road surface was not washed) and Pelayo site (where street washing was performed daily during night). Following the chemical characterization of the road dust particles the emission sources were resolved by means of Positive Matrix Factorization, PMF (Multilinear Engine scripting) and the mass contribution of each source was calculated for the two sites. Mineral dust, brake wear, tire wear, carbonaceous emissions and construction dust were the main sources of road dust with mineral and construction dust being the major contributors to inhalable road dust load. To evaluate the effectiveness of street washing on the emission sources, the sources mass contributions between the two sites were compared. Although brake wear and tire wear had lower concentrations at the site where street washing was performed, these mass differences were not statistically significant and the temporal variation did not show the expected build-up after dust removal. It was concluded that the washing activities resulted merely in a road dust moistening, without effective removal and that mobilization of particles took place in a few hours between washing and sampling. The results also indicated that it is worth paying attention to the dust dispersed from the construction sites as they affect the emission strength in nearby streets. ©Taiwan Association for Aerosol Research.

The use of a driving simulator can be preferable to on-road experiments for cost-efficient rapid prototype testing or dangerous driving scenario evaluations. However, the mismatch of the simulator and the actual driving environment might alter a driver's behavior. This might lead to deceptive results that are not applicable to reality. Therefore, before using the simulator, one must assess its fidelity. In this paper we validate a three-screen desktop simulator by comparing the simulator and on-road tests for a driver's perception of the environment and their driving response. The validation results point to considerable perception alteration and change of driving behavior on the simulator. We propose using the simulator validation results to create a mapping from the simulator domain to the real world to overcome the distortion. The mapping is in the form of a transformation of probability density functions associated with driving response characteristics. In this work we focus on the driving tasks of vehicle following and lane changing to demonstrate the approach. 46 433 439 Sponsors: Conference code: 114781

Noise control for an urban district starts by understanding the actual noise situation. A correct understanding is needed to take appropriate and cost efficient measures. For a noise burdened urban district, surrounded by road and rail traffic, the traffic noise as well as the annoyance has been measured. The size of the district is approximately one square km. With the help of 35 microphones, applied in a scalable sensor network, the time-varying sound levels were recorded. These results were coupled to an engineering model to obtain the sound levels for the complete district as well as to discriminate between road and rail traffic noise. Also, a data assimilation technique has been applied to increase the agreement between the measurement and model results. For example, for Lden sound levels the standard used source strengths for road and rail needed to be adapted to better match the sound level measurement results. In a separate paper these corrected sound levels at the façades are coupled to annoyance survey results to derive a local exposure-response relation. The annoyance survey also indicated the importance of peak levels and vibrations. This is further investigated by considering the measured noise dynamics.

Driving simulators have become an established tool in driver behaviour research by offering a controllable, safe and cost-effective alternative to real world driving. A challenge for using driving simulators as a research tool has been to elicit driving behaviour that equals real world driving. With respect to driver headways few studies have made a direct comparison between behaviour in real and virtual environments. The present study compared driver headway choice in a driving simulator and in an instrumented vehicle. Twenty-two participants carried out instructions to either change their headway to a specific value or to choose a headway as they would normally do. The speed of the lead vehicle (80, 100 or 120 km/h) as well as the target headway (1, 1.5, 2 s) were varied between trials. Specific headway instructions were provided in seconds as well as metres. The attained headways were compared between the virtual and the real environment. Results show no significant difference between headway choice in the simulator and on a real road, neither for self-chosen nor for instructed headways. The results provide support for the use of driving simulators in studies on headway choice. © 2014 Elsevier Ltd. All rights reserved.

Noise control for an urban district starts by understanding the actual noise situation. A correct understanding is needed to take appropriate and cost efficient measures. For a noise burdened urban district, surrounded by road and rail traffic, the traffic noise as well as the annoyance has been measured. The size of the district is approximately one square km. With the help of 35 microphones, applied in a scalable sensor network, the time-varying sound levels were recorded. These results were coupled to an engineering model to obtain the sound levels for the complete district as well as to discriminate between road and rail traffic noise. Also, a data assimilation technique has been applied to increase the agreement between the measurement and model results. For example, for Lden sound levels the standard used source strengths for road and rail needed to be adapted to better match the sound level measurement results. In a separate paper these corrected sound levels at the façades are coupled to annoyance survey results to derive a local exposure-response relation. The annoyance survey also indicated the importance of peak levels and vibrations. This is further investigated by considering the measured noise dynamics.

This study aims to develop a simulation/optimization model for the solution to the problem of determining on-street parking places in urban road networks. The problem is dealt within the Discrete Network Design (DND) context due to the binary decision variables and the bi-level programming technique is used for the solution of the problem. The upper level represents the determination of on-street parking places while the reaction of drivers’ to the design is handled in user equilibrium manner in the lower level. The upper level problem is formulized as a non-linear mixed integer programming problem and the meta-heuristic Harmony Search (HS) optimization technique is employed for the solution. In the proposed model, VISUM traffic analysis software is utilized as the simulation tool for solving the lower level problem. The performance of the proposed model is tested on Sioux-Falls road network which has widely been used on DND studies in the previous works. Results show that determining optimal or near-optimal on-street parking places may be achieved by using the proposed model. © Springer International Publishing Switzerland 2014.

Annoyance reactions to different types of landing procedures were addressed in a controlled laboratory setting using a Virtual Community Noise Simulator (VCNS) with a head mounted display.Participants, standing on a virtual countryside road, experienced four types of descentflyovers by an A330 aircraft: A regular descent flyoverat 2000ft and CDAs at respectively 3000, 4000 and 5000ft. These types of landing procedures are representative of flights approaching Amsterdam AirportSchiphol(AAS)in the Netherlands. Sound recordings for the VCNS were made on acountryside road and adjusted to match the indicated altitudes. After each flyover, participants were asked to rate their noise annoyance during the previous minute. Preliminary results showed that the 3000ft CDA was rated as the most annoying, followed by the ratings of the regular landing procedure and higher CDAs.These results could indicate that aCDA procedure, despite having lower LAmax and similar SEL levels, may still reach higher annoyance ratings due to longer flyover durations.

Annoyance reactions to different types of landing procedures were addressed in a controlled laboratory setting using a Virtual Community Noise Simulator (VCNS) with a head mounted display.Participants, standing on a virtual countryside road, experienced four types of descentflyovers by an A330 aircraft: A regular descent flyoverat 2000ft and CDAs at respectively 3000, 4000 and 5000ft. These types of landing procedures are representative of flights approaching Amsterdam AirportSchiphol(AAS)in the Netherlands. Sound recordings for the VCNS were made on acountryside road and adjusted to match the indicated altitudes. After each flyover, participants were asked to rate their noise annoyance during the previous minute. Preliminary results showed that the 3000ft CDA was rated as the most annoying, followed by the ratings of the regular landing procedure and higher CDAs.These results could indicate that aCDA procedure, despite having lower LAmax and similar SEL levels, may still reach higher annoyance ratings due to longer flyover durations.

Cooperative systems require the presence of multiple cooperative ITS stations to be effective and able to cooperate. Testing a single cooperative vehicle or road side unit will require a large number of other cooperative vehicles. Equipping additional test vehicles is expensive on hardware, drivers, and test facilities. It is also time consuming for installation and updating, and to organize test vehicles and drivers for running test scenarios. The Dutch Integrated Test site for Cooperative Mobility (DITCM) provides a cost and time efficient alternative to test a single cooperative vehicle in daily traffic with any penetration rate of cooperative vehicles. Cooperative messages are emulated from real time monitoring of normal vehicles driving on the same public road in the vicinity of the test vehicle. These messages are emulated and broadcasted in real time to the test vehicle to provide a cooperative awareness that fully consistent with its onboard sensor data and traffic situation.

Capacity measurement of roads under mixed traffic conditions as prevailing in India is ambiguous as it varies with time, composition of traffic and roadway encroachments. High incidence of slow moving vehicles and tricycles adds to the problem. Volume - capacity ratio appears to be an inadequate measure of defining level of service under mixed traffic situations. An attempt is made in this paper to explore the possibility of presenting unconventional parameters like standard deviation of speed, co-efficient of variation of speed and acceleration noise as possible measures of level of service. Tentative ranges of acceleration noise are proposed in association with flow and speed to explain level of service of urban roads catering to mixed traffic. The results are based on a study conducted in Madras, a major metropolitan city of India.

SUMMARY An optimal preview control algorithm is applied to a two degree of freedom(dof) vehicle model travelling with constant velocity on a randomly profiled road. The road roughness is modelled as a homogeneous random process being the output of a linear first order filter to white noise. The input from the road irregularity is assumed to be measured at some distance in front of the vehicle and this measured infonnation is utilized by the active controller to prepare the system for the ensuing input. The preview control algorithm is obtained by minimizing a quadratic performance index and by describing the average behaviour of the system by the covariance matrix of the vehicle response state vector. Results are presented for full state feedback and significant improvements in sprung mass acceleration, suspension working space and road holding are observed.

In this study we investigated the effectiveness of high power illuminators that are intended to be used as warning devices or non-lethal weapons to deny car drivers their view on the outside world through windscreens. The test is based on a measurement of the amount of veiling glare resulting when a high intensity light source hits a windscreen. We measured the veiling glare for new, used and colored windscreens that were either clean or dirty. We found no significant difference between the scatter function for new, used and colored windows. The scatter function for dirty windscreens is a factor 14 larger than for clean windscreens. We also derived a method to assess the impact of the illumination of a windscreen by a high intensity light source on driving behavior. The method is based on the assumption that drivers reduce their speed when veiling glare reduces the detection distance of objects on the road. Estimates of respectively the detection distance for objects on the road and the maximum safe driving speed are directly related to operational requirements, and can therefore be used to assess the operational effectiveness of high intensity light sources as powerful warning devices or non-lethal weapons.

A model based monitoring system is applied on a local scale in an urban area to obtain a better understanding of the traffic noise situation. The system consists of a scalable sensor network and an engineering model. A better understanding is needed to take appropriate and cost efficient measures, especially when changes to the local infrastructure are proposed. The monitoring system provides information about the sound level distribution in the area in time and place. This can be used to create dynamic noise maps or to characterize the soundscape in the area. Results of a field test of two weeks in an urban area of 400 by 200 meters are used. Three different areas are considered: 1) the main road which is the major source for traffic noise, 2) a quiet street, and 3) a quiet courtyard. The noise level measurements near the main road are compared with the engineering model results. Next, with the use of actual source levels from the measurements, the sound levels in the quiet street and the quiet courtyard are calculated. By comparing the model results with measurements in these areas the parameters in the model are updated to better reflect the actual situation. © 2013 Acoustical Society of America.

A model based monitoring system is applied on a local scale in an urban area to obtain a better understanding of the traffic noise situation. The system consists of a scalable sensor network and an engineering model. A better understanding is needed to take appropriate and cost efficient measures, especially when changes to the local infrastructure are proposed. The monitoring system provides information about the sound level distribution in the area in time and place. This can be used to create dynamic noise maps or to characterize the soundscape in the area. Results of a field test of two weeks in an urban area of 400 by 200 meters are used. Three different areas are considered: 1) the main road which is the major source for traffic noise, 2) a quiet street, and 3) a quiet courtyard. The noise level measurements near the main road are compared with the engineering model results. Next, with the use of actual source levels from the measurements, the sound levels in the quiet street and the quiet courtyard are calculated. By comparing the model results with measurements in these areas the parameters in the model are updated to better reflect the actual situation. © 2013 Acoustical Society of America.

In this study we investigated the effectiveness of high power illuminators that are intended to be used as warning devices or non-lethal weapons to deny car drivers their view on the outside world through windscreens. The test is based on a measurement of the amount of veiling glare resulting when a high intensity light source hits a windscreen. We measured the veiling glare for new, used and colored windscreens that were either clean or dirty. We found no significant difference between the scatter function for new, used and colored windows. The scatter function for dirty windscreens is a factor 14 larger than for clean windscreens. We also derived a method to assess the impact of the illumination of a windscreen by a high intensity light source on driving behavior. The method is based on the assumption that drivers reduce their speed when veiling glare reduces the detection distance of objects on the road. Estimates of respectively the detection distance for objects on the road and the maximum safe driving speed are directly related to operational requirements, and can therefore be used to assess the operational effectiveness of high intensity light sources as powerful warning devices or non-lethal weapons.

Published version of an article in the journal: Mathematical Problems in Engineering. Also available from the publisher at: http://dx.doi.org/10.1155/2013/986584 Open access The road surface roughness is the main source of kinematic excitation of a moving vehicle, which has an important influence on vehicle performance. In recent decades, random road models have been widely studied, and a four-wheel random road time domain model is usually generated based on the correlation of the four-wheel input, in which a coherence function is used to describe the coherence of the road input between the left and right wheels usually. However, during our research, there are some conditions that show that the road PSD (power spectral density) of one wheel is smaller than the other one on the same axle. Actually, it is caused by the uncorrelation between the left- and right-wheel road surface roughness. Hence, a frequency compensation algorithm is proposed to correct the deviation of the PSD of the road input between two wheels on the same axle, and it is installed in a 7-DOF vehicle dynamic study. The simulation result demonstrates the applicability of the proposed algorithm such that two-wheel road input deviation compensation has an important influence on vehicle performances, and it can be used for a control system installed in the vehicle to compensate road roughness for damper tuning in the future.

International audience; Among the general problematic of the HEV power trains, the most critical point is the determination of the power-split ratio between the mechanical and the electrical paths, known as the energy management strategy (EMS). Many EMS are proposed in the literature, and can be grouped in two categories: the local optimization EMS and the global optimization EMS. The local optimization category corresponds to the EMS based on human expertise and the knowledge of the power train components efficiency maps. Thus, the local optimization EMS manages the power train operations by referring to predefined rules. The drawback of such strategies is that it brings an instantaneous fuel consumption optimization, and does not fully optimize the fuel consumption over the whole trip. Therefore, additional fuel savings are still possible. This paper presents an overall optimized predictive EMS for the Toyota Hybrid System (THS-II) power train of the Prius. The proposed EMS is based on Dynamic Programming (DP), where the prior knowledge of the route is required in order to predetermine the power-split ratio and optimize the fuel consumption for the whole predicted route. The DP EMS proposed for the THS-II power train is designed with a very short computation time, intended to be implemented in real-time applications. The potential of this DP-controller in reducing fuel consumption on regulatory cycles are computed and compared to a rule-based controller and to the Prius published fuel consumption results. Finally, the fuel reduction enhancements of the DP-controller are computed for real road tests achieved on a MY06 Prius in Ile-de-France, by comparing to the associated observed consumption measurements.

This study investigates (i) the link of land use and road design on pedestrian safety and (ii) the effect of the level of spatial aggregation on the frequency of pedestrian accidents. For this purpose, pedestrian accident frequency models were developed for New York City based on an extensive dataset collected from different sources over a period of 5 years. The assembled dataset provides a rich source of variables (land-use, demographics, transit supply, road network and travel characteristics) and two different crash frequency outcomes: total and fatal-only collision counts. Among other things, it was observed that the census tract analysis (disaggregate data) provides more insightful and consistent results than the analysis at the zip code level. The results indicate that tracts with greater fraction of industrial, commercial, and open land use types have greater likelihood for crashes while tracts with a greater fraction of residential land use have significantly lower likelihood of pedestrian crashes. Moreover, census tracts that have a greater number of schools and transit stops - which are determinants of pedestrian activity - are more likely to have greater crashes. Results also show that the likelihood of pedestrian-vehicle collision increases with the number of lanes and road width. This suggests that retrofitting or narrowing the roads could possibly reduce the risk of pedestrian crashes. � 2011 Elsevier Ltd.

Two controllers for an automotive suspensions with Magneto-Rheological (MR) dampers are proposed. One is a model-based using the Linear Parameter Varying (LPV) approach, and the other is a model-free controller with a Frequency Estimation Based (FEB) principle. The LPV controller includes an experimental nonlinear model of an MR damper using only one scheduling parameter. A comparison with a several semiactive controllers for comfort and road holding is discussed. The FEB controller is the best option based on frequency and time response analysis for comfort (1020), suspension deflection (3050), and road holding (15). © 2012 Jorge de Jesús Lozoya-Santos et al.

Determining the optimum signal settings in a road transportation network is an important issue for providing shorter travel time and lower fuel consumption. In the Stochastic EQuilibrium Network Design (SEQND) context, traffic signal setting problem has been widely formulated as an optimization problem which is addressed with both deterministic and heuristic approaches. While deterministic approaches such as gradient-based methods are preferred, they may not be effective since the problem contains several local optima and the decision space is highly convoluted. Recently, heuristic global search approaches such as Genetic Algorithms (GAs) are utilized to solve the SEQND problem which may be non-convex in nature. Although heuristic approaches are very effective at exploring the search space, they may require relatively long time to find the global optimum solution. Thus, a hybrid approach, which utilizes a local search method that fine-tunes the solution of the global search method, may provide more accurate results for SEQND problem. Thus, this study proposes " Hybrid Harmony Search and Hill Climbing with TRANSYT" (HSHCTRANS) model to solve the SEQND problem. In the HSHCTRANS model, meta-heuristic Harmony Search (HS) algorithm is employed as a global search method while the TRANSYT hill climbing routine is used for fine-tuning. It has been applied to an example signalized road network. The effectiveness of the hybrid HSHCTRANS over the HS and Genetic Algorithm (GA)-based models has been investigated in terms of network performance index (PI). Results showed that the hybrid HSHCTRANS model provided about 11% improvement when it is compared with GA-based model. © 2012 Elsevier Ltd.

International audience; The year 2000 radiative forcing (RF) due to changes in O 3 and CH 4 (and the CH 4-induced stratospheric water vapour) as a result of emissions of short-lived gases (oxides of nitrogen (NO x), carbon monoxide and non-methane hydrocarbons) from three transport sectors (ROAD, maritime SHIPping and AIRcraft) are calculated using results from five global atmospheric chemistry models. Using results from these models plus other published data, we quantify the uncertainties. The RF due to short-term O 3 changes (i.e. as an immediate response to the emissions without allowing for the long-term CH 4 changes) is positive and highest for ROAD transport (31 mW m À2) compared to SHIP (24 mW m À2) and AIR (17 mW m À2) sectors in four of the models. All five models calculate negative RF from the CH 4 perturbations, with a larger impact from the SHIP sector than for ROAD and AIR. The net RF of O 3 and CH 4 combined (i.e. including the impact of CH 4 on ozone and stratospheric water vapour) is positive for ROAD (þ16(AE13) (one standard deviation) mW m À2) and AIR (þ6(AE5) mW m À2) traffic sectors and is negative for SHIP (À18(AE10) mW m À2) sector in all five models. Global Warming Potentials (GWP) and Global Temperature change Potentials (GTP) are presented for AIR NO x emissions; there is a wide spread in the results from the 5 chemistry models, and it is shown that differences in the methane response relative to the O 3 response drive much of the spread.

11 páginas, 18 figuras, 3 tablas.-- PACS no. 4350.Lj, 43.50.Qp, 43.50.Rq, 43.50.Sr, According to European Directive 2002/49/CE, EU state members had to compile a strategic noise map no later than 30 June 2007 and a corresponding action plan no later than 18 July 2008 for all agglomerations with more than 250,000 inhabitants and for all major airports, roads and railways. A study on environmental noise was thus conducted for the city of Palma de Mallorca (Spain) using a commercial noise prediction package. The noise level assessment reveals a troublesome situation that requires an urgent noise action plan. In this report, various noise mitigation measures are analysed considering not only the reduction of noise and the number of people that can benefit from these measures, but also the net monetary benefits generated. Given the possible options, it is clear that to achieve the best long-term solution, global noise abatement measures (i. e., traffic management) and local measures (i. e., noise screens) should be combined.

GPS traces can track actual time and coordinates of regular vehicles going their own business, and it is easy to scale to the entire area with an accuracy of 6 to 10 meters in normal condition. As a result, extracting road map from GPS traces could be an alternative way to traditional way of road map generation. The basic idea of this paper is to describe a process which incrementally improves existing road data with incoming new information in terms of GPS traces. In this way we consider the GPS traces as measurements which represent a "digitization" of the true road. Although the accuracy of the traces is not too high, due to the high number of measurements an improvement of the quality of the road information can be achieved. Thus, this paper presents a method for integrating GPS traces and an existing road map towards a more accurate, up-to-data and detailed road map. First we profile the existing road by a sequence of perpendicular profiles and get the road's candidate sampling traces which intersect with the profile. Then we match the potential traces with the road and finally estimate the new road centerline from its corresponding traces. In addition to the geometry of roads we also mine attribute information from GPS traces, such as number of lanes. Furthermore, we explore the benefit of an incremental acquisition by a temporal analysis of the data.

The process of road extraction from high-resolution satellite images is complex, and most researchers have shown results on a few selected set of images. Based on the satellite data acquisition sensor and geolocation of the region, the type of processing varies and users tune several heuristic parameters to achieve a reasonable degree of accuracy. We exploit two salient features of roads, namely, distinct spectral contrast and locally linear trajectory, to design a multistage framework to extract roads from high-resolution multispectral satellite images. We trained four Probabilistic Support Vector Machines separately using four different categories of training samples extracted from urban/suburban areas. Dominant Singular Measure is used to detect locally linear edge segments as potential trajectories for roads. This complimentary information is integrated using an optimization framework to obtain potential targets for roads. This provides decent results in situations only when the roads have few obstacles (trees, large vehicles, and tall buildings). Linking of disjoint segments uses the local gradient functions at the adjacent pair of road endings. Region part segmentation uses curvature information to remove stray nonroad structures. Medial-Axis-Transform-based hypothesis verification eliminates connected nonroad structures to improve the accuracy in road detection. Results are evaluated with a large set of multispectral remotely sensed images and are compared against a few state-of-the-art methods to validate the superior performance of our proposed method. � 2011 IEEE.

The effect of an upgrade and its length is very significant for traffic flow characteristics. Road traffic in developing countries like India is highly heterogeneous comprising vehicles of wide ranging physical dimensions, weight and dynamic characteristics such as engine power, acceleration rate, etc. Due to these variations, the effect of grade on vehicles in heterogeneous traffic may vary significantly among vehicle categories. Variation in the level of the interaction between vehicles on upgrades may result in different sets of traffic flow characteristics. Hence, it is necessary to model traffic flow on upgrades and study, in depth, changes in traffic flow characteristics with alteration in the magnitude of an upgrade and its length. Computer simulation has emerged as an effective technique for modelling traffic flow due to its capability to account for randomness related to traffic. This study is concerned with applying a simulation model of heterogeneous traffic flow, named HETEROSIM, to study the traffic flow characteristics and performance of different vehicle types on upgrades of different magnitudes., Įkalnės ilgis – labai svarbus veiksnys, analizuojant transporto srauto charakteristikas. Transporto eismas tokiose besivystančiose šalyse kaip Indija yra labai heterogeninis ir apima transporto priemones, kurių fiziniai matmenys, svoris, dinaminės charakteristikos (variklio galingumas, greitis ir t. t.) labai skiriasi. Todėl skirtingų kategorijų transporto priemonių vertinimas šiame kontekste gali stipriai skirtis. Skirtingas sąveikos laipsnis tarp transporto priemonių įkalnėse gali turėti skirtingą įtaką transporto srauto charakteristikoms. Šiuo atveju svarbu suformuoti transporto eismo srautą įkalnėse ir nuodugniai išanalizuoti besikeičiančias srauto charakteristikas, kartu atsižvelgiant į kintantį įkalnės ilgį. Kompiuteriu sukurta situacija yra veiksmingas metodas transporto eismo srautui suformuoti, siekiant išsiaiškinti ir įvertinti atsitiktines transporto eismo situacijas. Šiame darbe panaudotas heterogeninio transporto srauto modelis HETEROSIM padės išanalizuoti įvairių transporto priemonių eismo srautų charakteristikas skirtingų dydžių įkalnėse.

In developing countries such as India, the traffic on roads is highly heterogeneous in nature, with vehicles of widely varying static and dynamic characteristics. This type of traffic is characterized by lack of lane discipline and free movement over the entire width of the roadway (laneless movement) based on availability of space. In such a regime of traffic flow, the phenomenon of merging of vehicles at junctions of two roads is complex and warrants further study. Merging maneuvers at T-junctions under congested traffic conditions were studied microscopically through video recordings. On the basis of these observations, models for normal and forced merging have been developed. Video data of merging maneuvers were employed to calibrate and validate the models. Such models can be used to simulate highly congested traffic flow in a realistic manner under heterogeneous traffic conditions. They can also give insight on devising better traffic control measures at such junctions.

Traffic density provides an indication of the level of service being provided to the road users. When the length and speed of the vehicles in a traffic stream varies significantly, however, it has been, found that, the concept of occupancy, rather than density, is more appropriate to describe traffic concentration. This is because of the reason that occupancy takes into account the variation in the speed and length of vehicles in its measurement. The value of occupancy, however, changes with change in the detection-zone length. Also, the measure, occupancy is not appropriate under heterogeneous traffic conditions, as the traffic has no lane discipline and hence, it is necessary to consider the whole of the width of the road as single unit to analyze the traffic flow. Hence, a new concept named, "area-occupancy" is proposed. Simulation technique has been used to validate the concept of area-occupancy. To check for the validity of the concept, the occupancy and area-occupancy of a homogeneous traffic stream were related to the density of the stream and it was found that area-occupancy can be a substitute for occupancy. Then, the concept of area-occupancy was applied for heterogeneous traffic and a relationship was developed between area-occupancy and traffic stream speed. The developed relationship is found to be logical indicating the appropriateness of the area-occupancy concept for heterogeneous traffic conditions. � 2010 by Science Press.

From research on PM2.5 and PM10 in 2007/2008 in the Netherlands, it was concluded that the coarse fraction (PM2.5-10) attributed 60% and 50% respectively, to the urban-regional and street-urban increments of PM10. Contrary to Scandinavian and Mediterranean countries which exhibit significant seasonal variation in the coarse fraction of particulate matter (PM), in the Netherlands the coarse fraction in PM at a street location is rather constant during the year. Non-exhaust emissions by road traffic are identified as the main source for coarse PM in urban areas. Non-exhaust emissions mainly originate from re-suspension of accumulated deposited PM and road wear related particles, while primary tire and brake wear hardly contribute to the mass of non-exhaust emissions. However, tire and brake wear can clearly be identified in the total mass through the presence of the heavy metals: zinc, a tracer for tire wear and copper, a tracer for brake wear.The efficiency of road sweeping and washing to reduce non-exhaust emissions in a street-canyon in Amsterdam was investigated. The increments of the coarse fraction at a kerbside location and a housing façade location versus the urban background were measured at days with and without sweeping and washing. It was concluded that this measure did not significantly reduce non-exhaust emissions. © 2010 Elsevier B.V.

This paper describes a semi-automatic system for road verification from high resolution orthophotos in an urban context. The system combines several road detection and road verification approaches from current literature to form a more general solution. Each road detection / verification approach is realized as an independent module representing a unique road model and thus a unique strategy. The object-wise verification result of each module is formulated as a binary decision between the classes "correct road" and "incorrect road". These individual decisions are combined by Dempster-Shafer fusion, which provides tools for dealing with uncertain and incomplete knowledge about the statistical properties of the data. For each road detection / verification module a function for confidence is introduced that reflects degree of correspondence of an actual test situation with an optimal situation according to the underlying road model of that module. Experimental results achieved with four different test sites in Japan demonstrate the potential and confirm the reliability of the new system. Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT) Japan Society for the Promotion of Science (JSPS)

Two major trends can be identified for powertrain control in the next decade. The legislation will more and more focus on in-use emissions. Together with the global trend to reduce the CO 2 emissions, this will lead to an integral drive train approach. To develop and validate this integral drive train approach, the need for a new chapter in powertrain testing arises. The climatic-altitude chamber, suited for heavy vehicles, serves a wide variety of testing needs. Ambient temperature can be controlled between â45 °C and +55 °C and ambient pressure can be reduced up to a level found at an altitude to 4000 meters. The chamber's dynamometers enable transient testing of heavy-duty engines and vehicles and the chamber is equipped with a comprehensive array of emission measurement capabilities, working under extreme conditions. With the final design of the chamber, three types of powertrain test set-ups are possible: Engine tests Engine in vehicle tests (engine speed versus torque cycles, e.g. WHTC simulation) Vehicle tests for road and non-road applications (real-world emission and performance) By testing the complete vehicle under varying ambient conditions, the interactions between subsystems can be studied and the robustness of products can be enhanced. With this tool, development, pre-calibration and performance evaluation of powertrain control systems is performed in a reliable and efficient test environment. To deal with the increasing complexity of powertrains and optimize overall performance, model-based control will become the standard in the coming decade. In that case, advanced models that accurately predict the powertrain performance under real-life conditions can be developed and validated using this facility. The availability of accurate models opens the route to model-based calibration and advanced diagnostics and optimal control based on models embedded in the controller. Copyright © 2010 SAE International.

This paper is concerned with modification and validation of a recently developed microsimulation model of heterogeneous traffic flow and application of the model to study the impact of provision of reserved bus lanes on urban roads. The impact of introduction of an exclusive bus lane is measured in terms of reduction in speed of other categories of motor vehicles, due to the consequent reduction in road space, over a wide range of traffic volume. The main finding of this paper is that if an exclusive bus lane is provided under highly heterogeneous traffic conditions (prevailing in Indian cities), then the maximum permissible volume to capacity ratio that will ensure a level of service of C for the traffic stream comprising all the motor vehicles, except the buses, in a typical eight lane divided urban road (14.5-m-wide road space per direction) is about 0.62. Through this study, a framework for justification of providing exclusive bus lane has also been defined. � 2010 ASCE.

The traffic volume and roadway capacity are the important basic inputs required for planning, analysis, and operation of roadway systems. Expressing traffic volume as number of vehicles passing a given section of road or traffic lane per unit time will be inappropriate when several types of vehicles with widely varying static and dynamic characteristics are comprised in the traffic. The problem of measuring volume of such heterogeneous traffic has been addressed by converting different types of vehicles into equivalent passenger cars and expressing the volume in terms of passenger car unit (PCU) per hour. The vehicles of highly heterogeneous traffic such as the one prevailing on Indian roads may occupy any convenient lateral position on the road, based on the availability of space, without any lane discipline. This study is concerned with the estimation of PCU values of vehicles in such traffic conditions, using microscopic simulation. The PCU values obtained for different types of vehicles, for a wide range of traffic volume and roadway conditions, indicate that the PCU value of a vehicle significantly changes with change in traffic volume and width of roadway. � 2010 ASCE.

In this paper the influence of heterogeneous traffic on the temporal variation of ambient PM10, PM 2.5 and PM 1 concentrations at a busy arterial route (Sardar Patel Road) in the Chennai city has been analyzed. The hourly PM concentration, traffic counts and average speed of the vehicles have been monitored at the study site for one week (19 th-25 th January 2009). Results indicated that the concentrations of coarse (PM 10) and fine PM (PM 2.5 and PM 1) concentrations at SP road are having similar trend during peak and non-peak hours, irrespective of the days. The PM concentrations showed daily two peaks corresponding to morning (8 to 10 am) and evening (7 to 9 pm) peak hour traffic flow. The PM10 concentration is dominated by fine particles (53% of PM2.5 and 45% of PM 1). The high PM 2.5/PM 10 ratio indicates that the majority of PM10 particles originate from re-suspension of road dust. The analysis of traffic flow at the study site showed that 2W, 3W and 4W are having similar diurnal trend as PM concentrations. This confirms that the 2W, 3W and 4W are the main emission source contributing to ambient PM concentration at SP road. The speed measurement at SP road showed that the average speed of 2W, 3W, 4W, LCV and HCV are 38, 40, 38, 40 and 38 km/hr and 43, 41, 42, 40 and 41 km/hr respectively for the weekdays and weekdays.

Applications of automatic steering constitute an active research field within automotive control systems. The steering performance of a vehicle can be evaluated in terms of the extent to which it is capable of following demanding road trajectories. Conventional yaw stability controllers used to restrict the extreme understeering or oversteering vehicle behavior are inevitably challenged by uncertain vehicle dynamics. We develop a simplified vehicle yaw dynamics model subject to steering angle rate constraints and introduce an adaptive yaw control design methodology in order to address possible design conflicts between steering angle rate constraints and achievable steering performance of the vehicle. Our parameter estimation scheme and adaptive control strategy can be employed in automatic steering applications with the promise of improved yaw stability performance in the presence of uncertain tire cornering stiffnesses and unknown road adhesion factor. ©2010 IEEE. 2904 2909 Conference code: 84289 Cited By :2

A sequential extraction protocol has been used to determine the solid-phase partition of 210Po and 210Pb in anoxic marine sediment from the roads of Cherbourg (France) in the central English Channel. Measurements were also obtained in pore waters, in which 210Po activities range between 1 and 20 mBq L-1 and 210Pb activities between 2.4 and 3.8 mBq L-1, with highest activities in the topmost layer. These activities are higher than in seawater, suggesting that sediment act as a source of both 210Po and 210Pb for overlying water. The 210Po profile in the pore waters is apparently correlated with those obtained for Fe, Mn and SO42-, suggesting an influence of early diagenetic processes on the 210Po solid-liquid distribution. In the sediment, 210Po is predominantly bound to organic matter or chromium reducible sulphides, and residuals (clay minerals and refractory oxides). Our results indicate that 210Po is not significantly bound to AVS, i.e. acid volatile sulphides: bioturbation could play a role by the early redistribution of 210Po bound to acid volatile sulphides in the sediment. 210Po, 210Pb and Pb exhibit differences in terms of distribution, probably due to a different mode of penetration in the sediment. This work provides information on solid and liquid distribution of 210Po and 210Pb in marine sediment. These data are very scarce in the litterature. © 2009 Elsevier Ltd. All rights reserved.

Large-scale use of leaded gasoline was an important source of the neurotoxin lead in the European environment. After a sequence of regulations on the allowed gasoline lead content and, eventually, a ban on the use of lead additives in gasoline, road transport was no longer considered a source of atmospheric lead. Currently a discrepancy exists between measured atmospheric lead concentrations and model-predicted concentrations, suggesting that lead emissions to the atmosphere may be underestimated. Recently it was suggested that lead emission from unleaded gasoline combustion is still an important source and may (partly) fill the gap between modelled and observed atmospheric lead concentrations. In this paper we assess the plausibility of the latter suggestion by following various emission estimation methodologies. The uncertainty of lead emissions from road transport is further reduced by chemical analysis of fuel samples. The result of our assessment is that lead from road transport fuel combustion is not the missing lead source needed to fill the gap between modelled and observed lead concentrations. Road transport is still a source of lead through brake wear and a small contribution from exhaust emissions but this contributes no more than 5-8% of the EU25 total emission. © 2009 Elsevier B.V. All rights reserved.

The introduction of local scale analysis in Integrated Assessment Modelling (IAM) requires an evaluation of road transport emission factors and local scale air quality models. The comparison of PM10 and PM2.5 over NOx delta (street level minus background) concentration ratios against emission ratio estimates, confirms the appropriateness of the COPERT methodology. The comparison also reveals the non-exhaust coarse fraction source in Stockholm to be three times the fine fraction in summer, but seven times that in winter. In London it is twice the fine fraction. The model intercomparison study shows that simple street canyon models can be sufficient for use in IAM. Copyright © 2009, Inderscience Publishers.

Two large-scale diesel pool fire engulfment tests were carried out on LPG tanks protected with intumescing materials to test the effectiveness of thermal coatings in the prevention of hot BLEVE accidental scenarios in the road and rail transport of LPG. A specific test protocol was defined to enhance reproducibility of experimental tests. The geometrical characteristics of the test tanks were selected in order to obtain shell stresses similar to those present in full-size road tankers complying to ADR standards. In order to better understand the stress distribution on the vessel and to identify underlying complicating phenomena, a finite element model was also developed to better analyze the experimental data. A non-homogeneous and time-dependent effectiveness of the fire protection given by the intumescing coating was evidenced both by finite element simulations and by the analysis of the coating after the tests. The results of the fire tests pointed out that the coating assured an effective protection of the tanks, consistently increasing the expected time to failure. The data obtained suggest that the introduction of fire protection coatings may be a viable route to improve the safety of the LPG distribution chain. © 2008 Elsevier B.V. All rights reserved. Chemicals / CAS: liquefied petroleum gas, 68476-85-7; Gasoline

This paper investigates the effects of dynamic road marking on the Ring around Amsterdam. This Ring is congested during most of the day, but especially during the peak periods in the morning and evening rush hours. The goal is to determine what (traffic) effects, if any, can be found by applying Dynamic Road Marking during the morning rush hours. The INDY model was used to estimate the effects. INDY is a dynamic assignment model that combines analytical simulation with a route choice component. The most significant results are (1) that the choice of route changes significantly with the added capacity on the Ring Road, (2) average speed increases on the Ring Road; and (3) negative effects on throughput are avoided.

Road traffic in India, is heterogeneous, and is characterized by the presence of vehicles with wide ranging static and dynamic characteristics. Generally, all these vehicles use the same road space without any segregation and this results in a variety of traffic mix, flows and densities over time and space. In this study, a newly developed heterogeneous traffic flow simulation model (HETEROSIM) has been used to develop, a set of speed-flow curves for traffic on road spaces of widths 7.5m, 11.0m and 14.5m (equivalent to two, three and four lanes). The developed speed-flow relationships are found to follow the standard pattern indicating the goodness of the model. These curves will be useful, in addition to estimate the capacity of the roads, to predict the traffic speed on divided roads for a given traffic volume over a wide range, which is an important input for planning of road networks and road traffic operations.

Large-scale use of leaded gasoline was an important source of the neurotoxin lead in the European environment. After a sequence of regulations on the allowed gasoline lead content and, eventually, a ban on the use of lead additives in gasoline, road transport was no longer considered a source of atmospheric lead. Currently a discrepancy exists between measured atmospheric lead concentrations and model-predicted concentrations, suggesting that lead emissions to the atmosphere may be underestimated. Recently it was suggested that lead emission from unleaded gasoline combustion is still an important source and may (partly) fill the gap between modelled and observed atmospheric lead concentrations. In this paper we assess the plausibility of the latter suggestion by following various emission estimation methodologies. The uncertainty of lead emissions from road transport is further reduced by chemical analysis of fuel samples. The result of our assessment is that lead from road transport fuel combustion is not the missing lead source needed to fill the gap between modelled and observed lead concentrations. Road transport is still a source of lead through brake wear and a small contribution from exhaust emissions but this contributes no more than 5-8% of the EU25 total emission. © 2009 Elsevier B.V. All rights reserved.

Two large-scale diesel pool fire engulfment tests were carried out on LPG tanks protected with intumescing materials to test the effectiveness of thermal coatings in the prevention of hot BLEVE accidental scenarios in the road and rail transport of LPG. A specific test protocol was defined to enhance reproducibility of experimental tests. The geometrical characteristics of the test tanks were selected in order to obtain shell stresses similar to those present in full-size road tankers complying to ADR standards. In order to better understand the stress distribution on the vessel and to identify underlying complicating phenomena, a finite element model was also developed to better analyze the experimental data. A non-homogeneous and time-dependent effectiveness of the fire protection given by the intumescing coating was evidenced both by finite element simulations and by the analysis of the coating after the tests. The results of the fire tests pointed out that the coating assured an effective protection of the tanks, consistently increasing the expected time to failure. The data obtained suggest that the introduction of fire protection coatings may be a viable route to improve the safety of the LPG distribution chain. © 2008 Elsevier B.V. All rights reserved. Chemicals / CAS: liquefied petroleum gas, 68476-85-7; Gasoline

Public-private partnership (PPP) road projects are highly leveraged capital-intensive projects. Lenders, which provide the major portion of financing in the form of debt instruments, undertake loan approval processes to examine the various aspects of the projects that could influence the debt servicing capability while making credit decisions. In view of this, project sponsors could also assess beforehand how desirable is the project from the debt financing perspective in order to facilitate timely arrangement of debt financing and avoid funding problems. The Desirability Rating Analytical Tool (DRAT) has been developed in order to enable the project sponsor to assess how desirable the project is from a debt financing perspective. DRAT uses the aggregation operator Choquet fuzzy integral to aggregate the information relating to the various aspects of PPP road projects that lenders take into account while making credit decisions. The application of DRAT is illustrated with an example of a PPP road project from a National Highways Development Programme undertaken by the National Highway Authority of India, Government of India. DRAT expressed the result of the information aggregation in the form of a desirability rating profile indicating the degrees of membership to different levels of desirability. The desirability rating profiles of the project provide valuable information for decision making and can help in formulating strategies on improving the performance of the project where it is not performing satisfactorily. � 2009 Taylor & Francis.

Vehicular ad hoc networks have emerged recently as a platform to support intelligent inter-vehicle communication and improve traffic safety and performance. The road-constrained and high mobility of the vehicles, their unbounded power source, and the emergence of roadside wireless infrastructures make VANETs a challenging research topic. A key to the development of protocols for intervehicle communication and services lies in the knowledge of the topological characteristics of the VANET communication graph. This article provides answers to the general question: how does a VANET communication graph look like over time and space? This study is the first one that examines a very large-scale VANET graph and conducts a thorough investigation of its topological characteristics using several metrics, not examined in previous studies. Our work characterizes a VANET graph at the connectivity (link) level, quantifies the notion of "qualitative" nodes as required by routing and dissemination protocols, and examines the existence and evolution of communities (dense clusters of vehicles) in the VANET. Several latent facts about the VANET graph are revealed and incentives for their exploitation in protocol design are examined. 502 511 Sponsors: IEEE ACM Imperial College London HP IBM Conference code: 79368 Cited By :40