Research On Timing Optimization And Simulation Of Isolated Signalized Intersection Based On The Emission Analysis

Traffic is vitals to the economic activities of urban. It is very important to thecity's economic development and people's living-level improvement. Automobilehas turn into the essential traffic transportation along with rapid evolution of thevehicle since 20th century. Automobile industry brings not only severalconvenience but a series of bewildering problems, such as environment pollution,traffic congestion, traffic accidents happening frequently and so on, which bringprodigious damage to lives and possessions of people. It has an advantagedstrongpoint that optimizing traffic management and control to improve vehicleemission t in order to change the present situation. This method mainly provideslogical measure of traffic management and control and seeks the high efficiency oftransportation and environment protection through studying vehicle emissioncharacteristic, micro emission model and the factors that effect vehicle emissionperformance in traffic flow.We know whether the signal timing of an intersection has been optimizednot only takes effect on traffic control directly but affects vehicles' running statusat intersection even to the entire city's traffic functioning. The former studiedoptimized signal timing using the pure traffic indexes such as delay and queuelength mainly, but seldom considered some indexes like environment, economyand other assistant factors, and therefore it is imperative under the situation toimprove traffic control from the point of view of traffic roads network's emissionestimation. That is to say choosing the representative vehicles' running status andemission characteristic to improve traffic control problem at a special intersectioncombined with reappearance of the traffic flow's emission characteristic using themethod of microcosmic simulation in order to optimize the signal timing finally.This paper lays heavy stress on analyzing light-duty's instantaneous emissioncharacteristic at a given intersection firstly. In this paper two typical vehicle to testin real time using OEM-2100 emission testing system at Gongnong Square arechosen, furthermore, a mass of data are collected and pretreated. It is moreimportant choosing NOx,HC and CO as study object to analyze emission rate atvarious operation status and period of time and affect emission rate from theparameters such as speed and acceleration. Secondly delay model at intersection,vehicle exhaust emission model and how to calculate vehicle emission gross areexpatiated with the analysis of an isolated signal intersection's traffic capacity andexhaust emission. These can offer a academic basis for reckoning signal cycle andtime allotted of green light. Finally simulation data are gained by investigation thestatus in quo of traffic and the signal timing of an Gongnong Square in Changchuncity using TSIS software as a breakthrough are studied. The main achievements ofthis paper are shown as follows:(1)While a vehicle travels at intersection, the large proportion of idle time andstarted frequently will not only increase delays and at the same time make outmuch more emissions to pollute the environment seriously. In cases of accelerationHC emission rate is running three times around than the idle emissions rate, andtwo times than the deceleration and cruise. After analyzed the Jetta emissions rateunder the vehicle various operating modes the emissions rate of acceleration isbiggest, next is deceleration, then is the cruise and the idling;(2)The emissions of morning and evening peak rush hours very higher, and theordinary time is lower. The morning peak time NOx withdrawal approaches time2.5 times even peak;Morning peak time HC withdrawal falls about 8% comparedto evening peak, actually that is approaching 2 times than the ordinary time hours;The evening peak times CO withdrawal is higher than the early peak approximately15%, is about actually 2.5 times than the ordinary period;(3)NOx emission rate is most sensitive to velocity changes, it increases markedlyas a super-linear speed growth trends. The average emission of HC and CO rate inthe low-speed is higher, with the higher speed emissions rate drop gradually,mainly because of the deterioration in the low-speed and Oil burning , while invehicle high speed Consumption, combustion engine is adequate, so fuelconsumption rate is low;With the instantaneous acceleration of change emissionrates dramatically, and there is a very strong law, When the acceleration increases,the rapid increase in emission rates, and the same result contrarily;(4)Analysis on the traffic capacity and emissions through an isolated signalsintersection control method expounded the delay models and vehicle emissionsmodels, and how to calculate vehicle tail gas emissions. These are the theoreticalbasis for signal cycle optimized and green time distributed using the lowestemissions as targets;(5)Simulation data are gained by investigation the status in quo of traffic and thesignal timing of an Gongnong Square in Changchun city using TSIS software as abreakthrough are studied. and to ensure that these data adequacy and accuracy tocalculate Simulated;TSIS simulation software as a starting point to the ChangchunCity signal distribution, analysis simulation results and the status of the junctionwith traffic TSIS simulation software to verify the validity and accuracy of theinvestigation;(6)According to the traffic engineering theory and the associated intersectiondesign and planning theory two reasonable signal distribution optimization are putforward, and make use of the simulation software to optimize parameters andanalyze simulation results;one optimization plan analogue result is three kind ofemissions NOx, HC and the CO total quantity has the reduction, reduced 0.63%,1.37% and 1.13%, separately. and the other optimization plan's delay time reduces0.42%, emissions of NOx have some drop, but the value of HC and CO emissionsto have the small scope elevate actually;with the two timing optimization plans tomake the contrast analysis, and took delay as the assistance validation target.Finally the first optimization plan as the optimal signal timing plan is obtained.This paper considers from one point of environment protection. It not onlyanalyzes the emission pollution status at a given intersection but optimizes thesignal timing using vehicle emission as an index and takes delay index as anassistant parameter to validate the level of signal timing. The study on signal timingusing emission as an index not only is benefit for improving traffic condition evento settle the problem of vehicle jam at intersection but considers trafficenvironment of urban roads to make vehicle move under a smooth, safe and cleancircumstance. The achievements of the study have a better maneuverability andpracticability. Furthermore it can provide theory basis of traffic environmentevaluation for local government even the whole nation, and moreover, it also canimpose positive effect on traffic environment's improvement for our country.