Dynamic User Optimal Signal Design at Isolated Intersections

At an isolated signalized intersection, short left-turn lanes may be provided to enhance intersection capacity and level of service. The capacity of an entire intersection depends not only on the effective green time per phase and the length of each short left-turn lane but also on the selected signal phase plan. This paper enumerates 16 typical signal phase plans for a four-leg intersection with protected left-turn phases. Given the existence of short left-turn lanes and the freedom to select signal phase plans, two optimization models are formulated. Numerical examples are carried out to illustrate the application of these models and show the sensitivity of the outcomes to impact factors. The orthogonal experiments show that the primary factor is whether a short left-turn lane is added on an approach and the demand distribution is the secondary factor in determining an optimal allocation of the time-space resources of an intersection. To analyse traffic flow operations under different signal phase sequences, the simulation tests are fulfilled using VISSIM under the assumption that the components of a signal phase plan and green splits are all identical. The simulated results indicate that the signal phase sequence for a specified approach may greatly affect traffic movements at an approach, and the leading green phasing is better than the lagging one for a specified approach when the left-turn bay length is short at the approach. Finally, two variations of the developed models are recommended for use and the procedure for the model application is provided in practice.

The nonlinear equation system approach to solving dynamic user optimal simultaneous route and departure time choice problems

This study develops a variational inequality (VI) formulation for the stochastic user equilibrium with a bounded choice set, known as the bounded choice model (BCM). A novel mapping is devised to facilitate the development of the VI formulation. The VI formulation offers a new avenue for analysing and solving the BCM. It is shown that all paths in the considered choice set should have an equal mapping at the optimal solution, which resembles the equilibrated travel cost in the user equilibrium (UE). The new formulation has two algorithmic benefits. First, an algorithm that solves a VI problem (i.e., the extragradient method) can outperform the method of successive averages (MSA) in large networks under a UE-type convergent measurement. Second, it is possible to avoid the column reduction procedure when finding the choice set that satisfies the BCM requirement because a projection-type algorithm that solves the VI formulation can assign zero flow to a path. This is more efficient than the MSA, which uses diminishing step sizes to update solutions over iterations, leading to a sublinear rate of convergence and small residual flows on paths that should carry zero flows. Numerical experiments are conducted to demonstrate the properties of the model and compare the performance of different algorithms using the Sioux Falls, Eastern Massachusetts, and Anaheim networks.

The GLOSA (Green Light Optimal Speed Advisory) system provides speed advice to drivers so that drivers can pass through congested intersections at right instant with shorter time and lower energy consumption. Traditional GLOSA system only considers the SPaT (Signal Phase and Timing) of traffic light. However, two another important factors, namely queuing effect and actual tracking error of drivers, are seldomly considered, which degrades the actual performance of the GLOSA system. Intelligent connected vehicles based on V2I (Vehicle to Infrastructure) have great application potential in solving this problem. In this study, firstly, a vehicle queue length estimation method based on V2I technology is proposed to predict the effective green light time. Secondly, a hierarchical GLOSA system is developed, where the upper layer provides the global recommended optimal speed aiming at minimizing energy consumption, while the bottom layer provides the modified recommended speed considering the driver's tracking error. Finally, the tracking error of the driver when executing the recommended speed is derived based on the real-world experiment. Corresponding simulation and field test platforms are also established. Results show that compared with the traditional GLOSA system, the improved GLOSA system considering the vehicle queuing effect and driving error can effectively improve the energy-saving performance of the vehicle.

Coordination control is implemented on the main public transport system to reduce delay and improve the operation efficiency of buses on urban arterial roadways. First, the concept of a dual-loop phase is introduced and a new phase structure and sequences are proposed. Then, optimization models of the common signal cycle and effective green light time are built. Second, a genetic algorithm is used to optimize signal offset in coordination control according to the driving characteristics of a bus. To evaluate the effect of coordination control, a delay function is established to describe the control effect according to theory of triangle delay. Finally, the main arterial road is selected for a case study. The main parameters, such as common signal cycle, effective green light time, and offset, are optimized using Lingo and MATLAB. Results show that the bus delay value tends to decline after implementing the algorithm and the 50th iterative optimization result is 20.13% lower than that of the first iteration.

Abstract. In this paper, we consider and study a new class of general-ized vector quasi-variational type inequalities and obtain some existencetheorems for both under compact and noncompact assumptions in topo-logical vector spaces without using monotonicity. For the noncompactcase, we use the concept of escaping sequences. 1. IntroductionThe vector variational inequality problem was initiated by Giannessi [11] in nite dimensional Euclidean spaces with applications. Later on many authors[6, 7, 12, 15, 24] generalized vector variational inequalities in abstract spacesin several ways. The vector variational-like inequality is one of the generalizedforms of vector variational inequalities [11]. In 1989, Parida et al [19] stud-ied the existence of solutions for variational-like inequalities in R n space andhave shown a relationship between variational like inequalities problems andconvex programming as well as with complementarity problems. The vectorvariational like inequality and generalized vector variational like inequality arepowerful tools to study non-convex vector optimization problems and convexand nondi erentiable vector optimization problems respectively, see [10, 18, 21].In 1973, Bensoussan and Lions [3] introduced the quasi-variational inequalityproblem (QVIP). Since then, many generalizations of the QVIP have beenappeared in the literature (see, for example, [1, 2]). In the last decade, becauseof applications in the optimization problems, mathematical programming andequilibrium problems, the QVIP has been intensively studied by many authors[5, 8, 16, 20, 22, 23, 25].In this paper, we consider the generalized vector quasivariational type in-equality problem (GVQVTIP) and obtain some existence theorems for solutions

19 - Variational Inequality Model of Ideal Dynamic User-Optimal Route Choice

This paper presents a fixed-point model for studying the morning commuting behavior in stochastic and time-dependent transport networks. The model considers the network uncertainty caused by supply and demand variations as well as the commuters’ perception errors on travel disutility. A new performance index called schedule reliability, i.e., the probability that commuters can arrive at destination on time or within a given time threshold early or late, is introduced to evaluate the network service level. The solution algorithm which combines the Monte Carlo simulation approach with the method of successive average is proposed together with a numerical example for demonstration.

Ordinarily, an actuated-coordinated signal control intersection has a fixed phase whose order is settled. Each phase has a minimum and maximum green time to fit the traffic’s randomicity and fluctuation. But if the traffic of some phases fluctuate remarkably and if there is little or no traffic comes in certain cycles or periods, the intersection runs the same phase number and order and sets the minimum green time accordingly. This would render the green time as obsolete and increase traffic delays in other phases. This paper considers the influence on drivers as caused by changing phase, optimizes the phase number and order of actuated-coordinated signal control intersection based on fuzzy control theory. It uses the intersection of Daxin Street and North Fourteen Street in Harbin as an example, simulates the intersection’s traffic signal control with Vissim, and estimates the result thus validating the optimized method’s availability and usability.

본 고는 신호교차로 영향권에서 수행되는 도로점용공사가 유발하는 신호교차로의 정지선에서의 유출 가능량, 다시 말해 포화교통류율의 변화를 산정하여 해당 접근 차로군의 용량을 계산할 수 있는 해석적 모형의 개발에 초점을 맞추고 있다. 해석적 모형이 가진 설명력의 간결함과 산정 정확도를 제고하기 위하여 선행연구의 모형논리를 크게 바꾸고 상당한 수정을 가하였다. 또 모형의 검증을 위해서 많은 노력이 보태졌는데, 다양한 미시 모의실험 결과와의 비교 뿐만 아니라 실제 공사현장에서 수집된 많은 자료를 바탕으로 하는 현장 대표 값들과의 비교 등이 수행되었다. 포화교통류율은 도로점용공사의 위치, 정지선과 공사구간과 이격거리, 개방 및 폐쇄 차로 수, 유효녹색시간 등에 상당히 민감하게 변화한다는 것이 확인되었으며, 공사현장의 특성을 구성하는 그와 같은 기하구조 및 신호운영관련 조건 등을 변수로 하는 제안 모형들은 아주 적은 오차 범위 내에서 성공적으로 포화교통류율을 산정해 낼 수 있음을 보여 주었다. This paper focuses on the development of analytical models for estimating the changes in saturation flow rates (SFR) at the stop-lines of a signalized intersection due to the existence of nearby work-zones, and thereby calculating the prevailing capacity values for specific lane groups. Major changes were incorporated in the logics of previous models and significant revisions have been made to secure the accuracy and simplicity. Furthermore, much attention was paid to model validation by making comparisons to both extensive simulation results and empirical data from various sites. It was found that SFRs are highly sensitive to the location of work-zones, the distance to each work-zone from the stop-line of a concerned approach, the number of lanes open and closed, and the effective green time. Using such geometric and operating conditions that constitute work-zone environment, the proposed models successfully estimated SFR values with a miniscule margin of error.

The impacts on traffic flows by Fuel Service Stations (FSS) located within 50 m vicinity of four (4) signalized intersections in Kumasi City were assessed. Changes in saturated flow rates, delays and lost times were the im-pact assessment indicators. Reduction in saturation flow rates ranged from low of 2 % to high of 56 %, depend-ing on orientations of the FSS to the intersections. Access to the FSS facilitated circumvention of the intersecti-ons, thereby easing congestion and delays. At one FSS, there was 7.9 % overall reduction in intersection delays, while in the other 3 FSS, the overall intersection delays were increased by 8 - 30 %. The actual lost times excee-ded the allotted signal operational time of 4 s, thereby reducing the effective green times. The existing traffic conditions were simulated for optimal traffic flow using Synchro 6.0 plus Sim Trafficware with traffic flow cha-racteristics, signal control data and geometric features of the intersections as inputs to determine the clearance lost times of critical movements. Comparison of outputs of the simulation runs of existing and control (steady flow states or intersections without FSS) indicated that if the operational signal timings were optimized to com-mensurate the actual lost times, the existing situations would experience reduced delays and congestions.

Although rain and other precipitation is common, analyses of signalized intersections based on the Highway Capacity Manual require clear weather and dry pavement conditions. Three factors may be affected by wet weather: saturation flow, effective green time, and progression. Saturation headway may lengthen, effective green may shrink, and progression may worsen in wet conditions. As a result, signalized intersection operations become less efficient. This is demonstrated in the longer delays estimated for five sample intersections. A methodology was developed for the derivation of the probability of rainfall (Pwet) during the morning and evening peak hours for any intersection in the United States using readily available rainfall accumulation data from the National Oceanic and Atmospheric Administration. Once delay and level of service (LOS) are estimated for both dry and wet conditions, a weighted average is employed for estimating delays and LOS that represent the prevailing dry and wet peak period conditions at a signalized intersection.

New Baneshwor is one of the main intersections and the epicentre of the Kathmandu Valley. This study aims to analyze the capacity and level of Service at this intersection. Maitighar, Tinkune, Sankhamul, and Old Baneshwor are the primary locations it connects, as it is one of the valley's busiest and most crucial crossings. The Indo Highway Capacity Manual (Indo HCM) 2017 and Nepal Road Standard 2070 documents assess the intersection's performance. A directional classified traffic volume count is conducted to determine traffic flow during peak periods. Vehicles are manually counted based on their different types. The Saturation Flow rate (SF) is computed from the unit base saturation flow equation (USFₒ) by multiplying various adjustment factors for other directions and phases. The input parameters for calculating capacity are the saturation flow rate, effective green time, and total cycle duration for each direction. Total control delay and Degree of saturation for each leg and flow direction are used to calculate the Level of Service (LOS). The comparison between the v/c ratio and control delay at the New Baneshwor intersection using PCU values based on NRS and Indo HCM indicates significant differences in congestion levels and control delays, highlighting the impact of methodological variations on traffic performance evaluation. The performance of using PCU from NRS is higher than that of using PCU from Indo HCM. Using PCU values based on NRS and IndoHCM, it was ultimately discovered that the overall Level of Service (LOS) was F for both the morning and evening peak hours.

This paper proposes a partition-based speed guidance strategy for mixed traffic of Human-driven Vehicles (HVs) and Connected Automated Vehicles (CAVs) at signalized intersections. To synergistically optimize efficiency, comfort, safety and emissions, a segmented jerk model is established based on the platoon's Effective Green Time (EGT). Four guidance schemes are formulated and validated via VISSIM simulations under various Market Penetration Rates (MPR). Results indicate significant improvements: the standard deviation of acceleration decreases by up to 14.7%, while queue time, delay, and stops are reduced by up to 86.7%, 87.5%, and 84.7%, respectively. Furthermore, fuel consumption drops by 17.8%, and pollutant emissions (CO, CO2, HC) decrease by up to 20.3%. The strategy successfully achieves multi-objective optimization while ensuring smooth driving.

We consider a new class of multiplier interior point methods for solving variational inequality problems with maximal monotone operators and explicit convex constraint inequalities. Developing a simple Lagrangian duality scheme which is combined with the recent logarithmic-quadratic proximal (LQP) theory introduced by the authors, we derive three algorithms for solving the variational inequality (VI) problem. This provides a natural extension of the methods of multipliers used in convex optimization and leads to smooth interior point multiplier algorithms. We prove primal, dual, and primal-dual convergence under very mild assumptions, eliminating all the usual assumptions used until now in the literature for related algorithms. Applications to complementarity problems are also discussed.