Estimation of Intersections Traffic Capacity Taking into Account Changed Traffic Intensity Transportation Research Procedia 20 ( 2017 ) 2 – 7 2352 1465 © 2017 The Authors Published by Elsevier B V Thi[.]
Available online at www.sciencedirect.com ScienceDirect Transportation Research Procedia 20 (2017) – 12th International Conference "Organization and Traffic Safety Management in large cities", SPbOTSIC-2016, 28-30 September 2016, St Petersburg, Russia Estimation of Intersections Traffic Capacity Taking into Account Changed Traffic Intensity Aleksandr Afanasyev 1a, Dmitrii Panfilov 2b* Saint Petersburg Mining University, 2, 21st Line, St Petersburg 199106, Russia Traffic Committee Department Manager (Saint-Petersburg), 16A Ispolkomskaya str., Saint Petersburg, 191167, Russia Abstract The factors affecting traffic intensity have been determined, and the situations of controlling traffic flows at city highways have been discussed taking into account actual traffic capacity of the roads A concept of adaptability with respect to road traffic provision (RTP) has been given The RTP system has been presented as a «black box» in the context system analysis A dependence of determining indicator of adaptability of a signal-controlled intersection to the changed traffic flows has been proposed and the quantitative intervals making it possible to select intersections on the basis of actual duration of traffic-light control cycle have been acquired © Published by Elsevier B.V B.V This is an open access article under the CC BY-NC-ND license © 2017 2016The TheAuthors Authors Published by Elsevier (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the organizing committee of the 12th International Conference "Organization and Traffic Peer-review under responsibility of the organizing committee of the 12th International Conference “Organization and Traffic Safety Safety Management in large cities" Management in large cities” Keywords: Traffic intensity, adaptability indicator, capacity, traffic flows, safety, town highways, signal-controlled intersections Introduction The road traffic accidents continue to remain one of the major issues of the modern society So, according to the World Health Organization 1.25 mln people die every year in the world, while the traffic accidents remain to be the cause of death No.1 for people at the age of 15 to 29 years [World Health Organization, 2015] There were 184 * Corresponding author: E-mail address: a.s.afanasev@mail.ru a, Dmitry.panf@yandex.ru b* 2352-1465 © 2017 The Authors Published by Elsevier B.V This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the organizing committee of the 12th International Conference “Organization and Traffic Safety Management in large cities” doi:10.1016/j.trpro.2017.01.002 Aleksandr Afanasyev and Dmitrii Panfilov / Transportation Research Procedia 20 (2017) – thousand road accidents in Russia in 2015, in which more than 23 thousand people died and more than 231 thousand people suffered injuries of different degree of severity Even though, the death toll decreased by 14.7%, while the injury rate decreased by 8.6% as compared with 2014, the figures are anyway unacceptable [State Traffic Inspectorate (2016)] The maximum quantity of road accidents takes place in the towns and populated localities (more than 128,600 accidents in 2015) The growing numbers of road vehicles in the cities demand improving capacity of city highways, streets and, especially, intersections, where the traffic intensity changes and a significant number of road accidents take place It seems appropriate to determine factors influencing the traffic intensity and quantitatively assess the traffic flows at the city highways taking into account a real traffic capacity of the roads Therefore, the assessment and increasing capacity of the roads, especially, at intersections taking into account the traffic intensity and effect of many factors have a great importance for the road traffic provision (RTP) Main text The traffic intensity is the most important factor determining the number of incidents It is possible to distinguish particular areas and zones in the street and road network, where the traffic reaches maximum level, whilst the intensity in the other areas is several times lower Such a spatial non-uniformity reflects, first of all, the nonuniformity of location of cargo- and passenger-forming stations and places of attraction thereof The factors determining the traffic intensity are presented in (Fig.1) [Egoshin et al (2015)] In many cases, not only the total flow intensity in this direction but the intensity accounting for one lane or the so-called specific traffic intensity [Inose and Khamada (1983)] is especially important in solving issues of traffic control under urban conditions The non-uniformity of traffic flows at different times has a paramount importance in the problem of road traffic organization Fig Factors determining traffic intensity The restrained urban conditions in densely populated areas reduce the journey length and, by the same, decrease the traffic intensity more than designing the dispersed construction settlement The increased traffic capacity of roads can bring about the increased traffic intensity, but new roads normally feature lower risk of incidents than the old roads The present-day taxes for carrier vehicles abroad (e.g., in Norway) contribute to the fact that the mileage today is lower by 30 thru 40% than, if these taxes were cancelled [Kremenets (2005)] Aleksandr Afanasyev and Dmitrii Panfilov / Transportation Research Procedia 20 (2017) – A concept of adaptability and keeping the values of quality and efficiency indicators at the nominal level as the property of object (system) in case of deviation of affecting environmental conditions from standard ones are of importance when considering the RTP system Regarding the issues of road traffic safety a feature of adaptability, as a non-prejudicial characteristic of RTP system, has not been given thorough consideration by the investigators The indicators, which help assess qualitative adaptability of RTP system for practical purposes have not been investigated as well The RTP system corresponds to a "black box" in the context of system analysis, where the affecting factors (natural-environment and climatic, organizational, road-related) are the incoming system parameters, while the indicators of RTP quality and efficiency (indicators of accident rate, speed, amount of delay, etc) are the out coming parameters (Fig.2) Fig RTP System in the form of "black box" The "black box" is understood as the object of investigation, which internal structure is unknown The "black box" concept has been suggested by W.R Ashby [Ashby (1959), Lopatnikov (2003)] In cybernetics it helps study behavior of systems, i.e system’s reactions to different external effects and at the same time abstract away from the internal structure thereof It is possible to perform certain investigations manipulating the inputs and outputs only The contemporary investigators emphasize that the same category of operational conditions may happen to be "easy" for some mechanisms and "difficult" for the other It can be proven, in particular, by the investigations of Scientific and Research Institute of Motor Transport and Scientific and Research Institute of Motor Transport and Motor Transport Engines, which have determined different influence of operational conditions on loading different mechanisms of a motor vehicle The importance of a feature of motor vehicle adaptability for increasing efficiency of motor transport operation is underlined in the works [Losavio (1973), Kuznetsov (2003), Reznik et al (1985)] Professor L.G Reznik was the first who began comprehensive study of adaptation as one of the most important characteristics of vehicle qualities He worded out the basic provisions of theoretical fundamentals of adaptability, defined the priority directions of investigations in this field He offers to use adaptability factor for quantitative assessment of vehicle adaptation to harsh operational conditions Aleksandr Afanasyev and Dmitrii Panfilov / Transportation Research Procedia 20 (2017) – The adaptability actually implies the object’s property to keep the values (of some) quality and efficiency indicators at the nominal level in case of deviation (of combination of factors) of environmental conditions influencing the object from the standard ones In order to solve the problem of assessing adaptability, a system-level approach is used, according to which the specified problem is tackled as a number of simplified problems on studying influence of any of environmental factors on any one operational indicators of a vehicle In particular, there are methods of assessing adaptability of motor vehicles to low ambient temperatures by fuel consumption, by toxicity of waste gas, methods of assessing adaptability of motor vehicles to non-uniformity of traffic by fuel consumption, methods of assessing adaptability of motor transport logistic system to a variable character of demand for cargo traffic, etc However, in order to solve in general a problem of assessing adaptability of an object to environmental factors, a comprehensive approach is required [Ermoshin et al (2015)] It is also necessary to introduce adaptability indicators for qualitative characteristic of adaptability and authentic determination of a degree of influence of variable character of the affecting factors on the efficient functioning of element of organization system and safety of traffic Let us identify a property of road traffic organization system adaptability to the intensity of traffic flows as a property of RTP system to keep the values of characteristic indicators at the nominal level in case of changed intensity of traffic flows It is possible to use a value of duration of traffic light control cycle, which depends on the intensity of traffic flows as an indicator of RTP system functioning at the signal-controlled intersection The closer is the duration value to the optimal one calculated on the basis of actual intensity, contents and speed data of traffic and pedestrian flows, geometrical characteristics of intersection, the higher is the intersection traffic capacity, the shorter is the time of delays at the intersection, the lower is the fuel consumption by the motor vehicles, the lower is the influence of traffic on the environment, the higher is the safety of this area of street and road network Thus, similar to indicator of motor vehicle adaptability to different factors of operational conditions, indicator of adaptability of signal-controlled intersection to a changed intensity of traffic flows may look as follows: k Tcact , Tcopt where, Т c is an actually implemented duration of traffic-light control cycle, sec.; Т c is an optimal duration of traffic-light control cycle at the given value (range of values) of traffic flow intensity, sec The values of intersection adaptability can fall within an interval (0; +f) In case the actual cycle durability is shorter than the optimal one the adaptability indicator tends to In this case an actual demand of traffic flows for a longer cycle of traffic-light control than the existing one remains not implemented, which brings about the emergence of waiting lines of transportation vehicles awaiting the traffic light clear signal (formation of traffic jams), increasing time of delivery of cargoes and passengers, increase of fuel consumption and harmful emissions into atmosphere The closer is the adaptability indicator to zero, the greater are the negative consequences of such a difference If the actual duration of the cycle exceeds the optimal one, the adaptability indicator tends to +f In this case the traffic light clear signal will stay switched on longer than it is required for passing a traffic flow in a given direction and there is a margin for reducing time of awaiting the clear signal for the other flows of transportation vehicles The reduced waiting time is understood as the increased efficiency of traffic process, reduced fuel consumption and harmful emissions into atmosphere The "farther" is the value of adaptability indicator from in this case, the higher is the economy margin In that case only, when the actual duration of cycle implemented at the intersection equals approximately the optimal one, the adaptability indicator values are close to In order to make the range of intersection adaptability characteristics formal, Table offers the following approximate intervals of the adaptability indicator (updating intervals is the purpose of further investigations in this respect): act opt Aleksandr Afanasyev and Dmitrii Panfilov / Transportation Research Procedia 20 (2017) – Table Intervals of adaptability indicator Values of adaptability indicator Characteristic of adaptability level of signal-controlled intersection (0; 0.33) (1.67; +f) Low level (0.33; 0.66) (1.33; 1.67) Middle level (0.66; 1.33) High level In order to determine assessment of adaptability of various elements of RTP system to the intensity of traffic flows, two signal-controlled intersections have been chosen, hereinafter referred to as "Object No.1" and "Object No.2" The traffic intensity has been calculated at the intersections "Object No.1" and "Object No.2" depending on the days of week and day time Further, a calculation of optimal cycle of traffic-light control has been performed for maximum, middle and minimum traffic intensity at the intersections "Object No.1" and "Object No.2" In accordance with conducted investigations the adaptability indicator will be determined on the basis of actual duration of traffic-light control cycle according to a formula Thus, the adaptability indicator from traffic flows intensity at this intersection will look as shown in Figure for actual, maximum, middle and minimal intensity Hence, the intersection "Object No.1" exhibits low and middle adaptability, while intersection "Object No.2" exhibits high adaptability at the intensity level being observed Conclusion Thus, the offered assessment of intersections traffic capacity with due account of changed traffic intensity can be used in studies to follow after its experimental verification and approbation taking into account multiple parameters of road situation Fig Adaptability indicator vs intensity of traffic flows at intersections "Object No.1" and "Object No.2" Aleksandr Afanasyev and Dmitrii Panfilov / Transportation Research Procedia 20 (2017) – References Ashby, W.R (1959) Introduction to Cybernetics Moscow: IL, pp 7–8 Egoshin, А.М., Skripka, А.V., Afanasyev, А.S (2015) Application of Automated Complex of Road Traffic Control Problems of Risks Management in Technosphere, 3(35): 51–56 Ermoshin, N.А., Afanasyev, А.S., Zmeyev, А.Т (2015) Assurance of Adaptive Development of Transportation and Logistical Systems under Conditions of Economical Threats In the III International Scientific and Practical Conference “Innovations at Transport”, (1): 66–70 State Traffic Inspectorate (2016) Records of the indicator of the road safety Available at: http:// stat.gibdd.ru/ (viewed on: 12.05.2016) Inose, Kh., Khamada, Т (1983) Road Traffic Control Transport, Moscow, p 249 Kremenets, Yu.А (2005) Technical Means of Traffic Organization Moscow: Transport, 279 p Kuznetsov, Е.S et al (2003) Technical Operation of Motor Vehicles Moscow: Nauka, 179 p Lopatnikov, L.I (2003) Black Box Dictionary of Economics and Mathematics.5th ed Moscow, 237 p Losavio, G.S (1973) Operation of Motor Vehicles at Low Temperatures Мoscow: Transport, 63 p Reznik, L.G., Romalis, G.М., Charkov, S.Т (1985) Adaptability of Motor Vehicles to Low Air Temperatures Tyumen: TGU, 104 p World Health Organization (2015) Traffic Injuries in the World At the wheel, (12): 30 ... in case of changed intensity of traffic flows It is possible to use a value of duration of traffic light control cycle, which depends on the intensity of traffic flows as an indicator of RTP system... the traffic flows at the city highways taking into account a real traffic capacity of the roads Therefore, the assessment and increasing capacity of the roads, especially, at intersections taking. .. the offered assessment of intersections traffic capacity with due account of changed traffic intensity can be used in studies to follow after its experimental verification and approbation taking