This paper proposes and illustrates a methodology to predict the fraction of time motor vehicles spend in different operating conditions from readily observable variables called emission specific characteristics (ESC). ESC describe salient characteristics of vehicles, roadway geometry, the roadside environment, traffic, and driving style (aggressive, normal, and calm). The information generated by our methodology can then be entered in vehicular emission models that rely on vehicle specific power, i.e., comprehensive modal emissions model (CMEM), international vehicle emissions (IVE), or motor vehicle emission simulator (MOVES) to compute energy consumption and vehicular emissions for various air pollutants. After generating second-by-second vehicle trajectories from a calibrated micro-simulation model, the authors estimated structural equation models to examine the influence of link ESC on vehicle operation. Authors' results show that 67% of the link speed variance is explained by ESC. Overall, the roadway geometry exerts a greater influence on link speed than traffic characteristics, the roadside environment, and driving style. Moreover, the speed limit has the strongest influence on vehicle operation, followed by facility type and driving style. Better understanding the impact on vehicle operation of ESC could help metropolitan planning organizations (MPOs) and regional transportation authorities predict vehicle operations and reduce the environmental footprint of motor vehicles.

Estimating impacts of emission specific characteristics on vehicle operation for quantifying air pollutant emissions and energy use

1. INTRODUCTION Actual high intensity of the traffic in the cities requires detailed analysis of issues and utilization of simulation systems for their complex solution. Advantage of utilization of simulation systems for needs of streamlining of traffic flows within the cities are the high-precision, large-scale, real-time interaction (Zheng, Zhang & Chen 2014), opportunities of observation of huge amount of variants, research and design of solution without intervention into the real system, minimization of risks caused by improper process, observation of variants which aren't built in reality yet. From the point of complex solution of urban intensity of traffic is necessary to take into account also the methods and principles of logistics and traffic (Comi & Rosati 2013), which are accurately used and incorporated in simulation models therethrough effectivity of achieved solutions for concrete environment and practise is increasing. Among criteria ,which clearly impact fluency and intensity of traffic, is possible to class amount of vehicles in time on the same road, resp. within the certain localization, current speed of vehicles (Huang et al. 2013), current state of restrictions and unforeseeable events, which may occur in time and given localization. Defined parameters influence not only freight transport but also passenger transport, whereby the individual streams amalgamate with each other, supplement each other, divide and combine independently on each other (Bohari, Bachok & Osman 2014). Many of urban transport systems are dependent on road infrastructure in towns and traffic nodes, whereby historically are not designed and laid out for the current load and traffic intensity. In the past it was typical to design crossroads which allow vehicles to go in any direction, which in a large extent causes cruising, braking and slowing of traffic flows sites (Van den Berg et al. 2003). Simulation systems allow to test and verify options (Kliment & Trebuna 2014), which do not allow traffic to turn in any direction but allow to manage traffic flows through the flow direction, thus the entire transport operation within the cities is streamlined (Pepucha et al. 2014). This is related to the acceptance of basic and necessary restrictions and limitations during the designing of urban transport systems. For the needs of simulation can be used a significant amount of simulation systems (witness, extendsim, gpss, simul 8, tecnomatix, ...), For the needs simulation is possible to use a significant amount of simulation systems (witness extends, GPSS, simul 8, Tecnomatix, ...) which allow any arbitrary and universal creation of simulation models, resp. which are specialized for a particular type of simulation of areas ,that they have to solve and at which they are more closely programmed just like Simulation of Urban Mobility--SUMO (Behrisch et al. 2011), resp. VISSIM (Lin, Yang & Gao 2013). If the models are well prepared, the differences in the results should be minimal. The main difference is in conformity, flexibility, creation and processing of generated simulation models. In many cases, resp. for specific situations of solved problems is necessary and appropriate to create a custom programming means, which is solving defined parameters much faster than universal software systems and equipment (Stangova 2014). 2. TRANSACTIONS, REQUIREMENTS--BASIC DYNAMIC ITEMS OF SIMULATION The advantage of simulation before experimentation with real system is mainly that is much cheaper, more flexible, safety, does not affect the on-going production, traffic, economical and other processes (Pekarcikova, Trebuna & Markovic 2015). For solve of urban traffic problems is simulation main topic branch. Life of cities is dependent on distribution of good. Different types of goods are distributed or collected daily on the main streets of the urban centres (Oliveira, Oliveira & Assis Correia 2014). …

Computer Simulation as Means of Urban Traffic Elements Design

A Simulation Study for Minimizing Operating Speed Variation of Multilane Highways by Controlling Access

Traffic speed is generally considered a main issue in roadway safety. Previous studies show that faster travel is not necessarily associated with an increased risk of being involved in a crash. When vehicles travel at the same speed in the same direction (even high speeds, as on interstates), they are not passing one another and cannot collide as long as they maintain the same speed. Conversely, the frequency of crashes increases when vehicles are traveling at different rates of speed. There is no doubt that the greater speed variation is, the greater the number of interactions among vehicles is, resulting in higher crash potential. This research tries to recognize all primary factors that are associated with speed variation (dispersion) on multilane highways, including roadway access density, which is considered to be the most distinct contributing factor. Additionally, other factors are considered for this purpose, for example: configuration of speed limits, characteristics of traffic volume, geometrics of roadways, driver behavior, environmental factors, etc. A microscopic traffic simulation method based on TSIS (Traffic Software Integrated System) is utilized to exploit mathematical models to quantify the influences of all possible factors on speed variation.

Jian Lu

Papers

A Simulation Study for Minimizing Operating Speed Variation of Multilane Highways by Controlling Access

A Simulation Study for Minimizing Operating Speed Variation of Multilane Highways by Controlling Access