Vehicle Delay Research Articles

Developing Warrants for Designing Continuous Flow Intersection

The increase in the left‐turn demand is the main cause of congestion at conventional intersections, and the traditional countermeasures are inadequate to solve this congestion due to the high changes in demand. This paper looks at the justifying threshold to redesign a signalized intersection from a conventional intersection (CI) to a continuous flow intersection (CFI) and create performance guidelines for decision‐makers and professionals deciding to consider the alternative. A performance comparison between the CI and CFI was conducted to define the main parameters affecting the operational performance. To accomplish the paper’s objective, candidate locations that have already implemented the CFI were identified, and the location with sufficient data for analysis was selected. After the consideration of different evaluation tools, microsimulation (VISSIM 8) was utilized to model the before and after conditions of the location. Using the field data, signal optimization and driving behavior parameter sensitivity analysis were performed to calibrate the models to replicate real‐life conditions. Afterwards, an experiment was designed to examine the different factors that affect the efficiency of each design. The experiment involved 72 different configurations of CFI and CI with 5 different volume levels and used two measures of effectiveness, average vehicle delay, and capacity to assess the results. The results were used to develop guidelines that will help the decision‐makers to decide which design should be considered, which will result in developing a decision support system that will accelerate finding which design is superior to others.

A novel analytical model for estimating vehicle delay at isolated signalised intersections

A novel analytical model for estimating vehicle delay at isolated signalised intersections

Signalized Corridor Timing Plan Change Assessment Using Connected Vehicle Data

Updates to traffic signal timing plans are expected to either improve operations or mitigate the effects of increased volumes. Longitudinal before-after studies are important when validating changes to traffic signal systems, but they have historically required field data collection as well as deployment of extensive detection and communication equipment. These infrastructure-based techniques are costly and hard to scale. This study utilizes commercially available connected vehicle (CV) trajectory data to assess the change in performance between August 2020 and August 2021 on a 22-intersection corridor associated with the implementation of a semi-automated adaptive control system. Approximately 1 million trajectories and 13.5 million GPS points are analyzed for weekdays in August 2020 and August 2021. The vehicle trajectory data is used to compute corridor travel times and linear referenced relative to the far side of each intersection to generate Purdue Probe Diagrams (PPD). Using the PPDs, operational measurements such as arrivals on green (AOG), split failures (SF), and downstream blockage (DSB) are calculated. Additionally, traditional Highway Capacity Manual (HCM) level of service (LOS) is estimated. Even though there was a 35% increase in annual average daily traffic (AADT), the weighted average vehicle delay only increased by two seconds, LOS did not change, AOG improved by 1%, and SF and DSB remained the same. Based on the small changes in operational performance and considering the increase in traffic volume it is concluded that the implementation of the semi-automated adaptive control system had a significant positive impact in the corridor. The presented framework can be utilized by agencies to use CV data to perform before-after studies to evaluate the impact of signal timing plan changes. The presented methodology can be applied to any location where CV trajectory data is available.

A novel analytical model for estimating vehicle delay at isolated signalised intersections

A novel analytical model for estimating vehicle delay at isolated signalised intersections

Mikrosimulasi Junction Metering dalam Meningkatkan Kinerja Simpang Menggunakan Software Vissim

Sight distance that’s not suitable with the standard, the queue time and the low awareness of vehicle users to give priority to other road users is the reasons for the hampered of traffic movements and reducing the use of intersections. The majority of vehicles for or on minor road use the opponent’s lane because there are no markers, this causes conflict crossing and merging. The researchers conducted study of Junction Metering which consisted of control and sensor settings to improve safety for road users. The method that used for analysis of intersection performance using calculation by software Vissim Full Version and Gap Raff and Hunt. Data collected in this study consisted of four aspects, (1) inventory of intersections; (2) traffic volume; (3) traffic speed; and (4) timelapse. Then alternative junction metering carried out with existing condition. Variable of comparison are level of service, queue length and vehicle delay. The Effectiveness alternative treatment using junction metering can reduce the queue length by 75% and vehicle delay by 17% with the average level of service is A.

Simulation-Based Evaluation of Variation in Left-Turn Paths in the Coordinated Intersection Management

Coordinated intersection management (CIM) has gained more attention with the advance of connected and autonomous vehicle technology. The optimization of passing schedules and conflict separation between conflicting vehicles are usually conducted based on the predefined travelling paths through the intersection area in the CIM. In real-world implementation, however, the diversity of turn paths exists due to multiple factors such as various vehicle sizes and automation control algorithms. The aim of this paper is to investigate how the variation in left-turn paths affects the feasibility and viability of optimal passing schedules, as well as the safety and efficiency of intersection operation. To do this, we start with identifying six typical left-turn paths to represent the variation. A scenario-based simulation is first conducted by using each of the paths as the nominal path. The optimal schedules and the corresponding alternative schedules are generated to calculate indicators for nominal performance, average performance, and robustness. The best path is selected in terms of schedule optimality and robustness. With schedules obtained by solving CIM models using the selected path, the left-turning CAVs are assumed to travel along one of the six paths randomly to simulate the path divergence. A surrogate safety measure, PET, is utilized to assess the safety of the intersection under CIM. The theoretical PET with the nominal path and the actual PET with the random path are calculated for each conflict event. Comparisons of two PET sets show the increase in conflict risk and vehicle delay. The conclusion can be drawn that the variation in left-turn paths causes the decline in safety level and travelling efficiency and should be considered in the CIM model to ensure safe and efficient implementation in the intersection.

Shared-phase-dedicated-lane based intersection control with mixed traffic of human-driven vehicles and connected and automated vehicles

Connected and automated vehicles (CAVs) and human-driven vehicles (HVs) are expected to coexist in the near future. CAV-dedicated lanes and phases have been explored to handle the uncertainty in the driving behavior of HVs in the mixed traffic environment. However, CAV-dedicated phases could significantly sacrifice HV benefits. This study proposes a shared-phase-dedicated-lane (SPDL)-based traffic control model at an isolated intersection with CAV dedicated lanes in the mixed traffic environment. In the proposed model, left-turn and through CAVs share CAV-dedicated lanes and cross the intersection during the shared phases with HVs. A three-level optimization model is developed. At the upper level, a standard NEMA (National Electrical Manufacturers Association) ring barrier structure is used for the signal optimization and barrier durations are optimized by dynamic programming to minimize the total vehicle delay. At the middle level, phase sequences and phase durations are optimized by enumeration for the given barrier from the upper level and the minimum vehicle delay is fed to the upper level. At the lower level, CAV platooning in the buffer zone and trajectory planning in the passing zone are conducted based on the signal timings of the barrier from the middle level and the travel time of CAVs is fed to the middle level. A rolling-horizon scheme is designed for the dynamical implementation of the proposed model with time-varying traffic conditions. The proposed model is applicable to intersections with more than two lanes in each approach and without shared lanes by left-turn and through HVs, which are commonly seen critical intersections in urban traffic control. Numerical studies validate the advantages of the SPDL-based control over the blue-phase-based control in previous studies in terms of average vehicle delay and intersection capacity. Further, the SPDL-based model is extended to serve as an alternative approach without the buffer zone.

Identification of Operational Design Domain for Autonomous Truck Mounted Attenuator System on Multilane Highways

The Autonomous Truck Mounted Attenuator (ATMA) vehicle system is a technology that leverages connected and automated vehicle (CAV) capabilities for maintenance of transportation infrastructure. Promoted by FHWA and state departments of transportation (DOTs), it is a niche CAV application in leader–follower style, intended to remove DOT workers from the following maintenance truck, to reduce fatalities in work zones. Because practicable guidance for deployment of this technology is largely missing in MUTCD, state DOTs have been making their own deployment criteria. In this manuscript, we focus on the operational design domain (ODD) problem—under what traffic conditions should ATMA be deployed. Modeling efforts are first focused on the derivation of an effective discharge rate that can be associated with a moving bottleneck caused by slow-moving ATMA vehicles on a multilane highway. Then, based on the demand input and discharge rates, microscopic traffic flow models calculate vehicle delay and density, which the Highway Capacity Manual (HCM) suggests are key indicators of a multilane highway’s level of service (LOS). In this way, the linkage between AADT and LOS is analytically established. NGSIM data is used for the model validation and shows that the developed model correctly captures the effective discharge rate discount caused by moving bottlenecks. The modeling results demonstrate that roadway performance is sensitive to the K factor and D factor, as well as the operating speed of ATMA and, if LOS = C is a desirable design objective, a good AADT threshold to use would be around 40,000 vehicles per day.

Research on Platoon Dispersion Delay of Traffic Flow considering Coordinated Control

To improve the traffic capacity and reduce the delay of signalized intersections, the delay of coordinated control intersections is studied. Based on the freedom and randomness of the speed change and considering the delay problem caused by the discrete behavior, the authors deduced a new delay model. Firstly, by analyzing the kinematic behavior of traffic flow under coordinated control, it is found that traffic flow reaches the downstream intersection in two different forms. The two forms were as follows: the tail vehicles of discrete traffic flow were truncated and the front vehicles of discrete traffic flow were stopped. Then, the authors deduced the new delay model by analyzing the two conditions. Finally, the delay of the two cases is analyzed, which can be used as the basis for setting the phase difference between coordinated control intersections. The correctness of the model is verified by designing two example coordinated control intersections under unsaturated flow with MATLAB. Results show that the discrete traffic flows will have different impacts on delay or traffic efficiency when they arrive at the downstream intersection in different forms. Through the analysis of the delay of vehicles, when the green split is less than 0.64, the tail truncation delay is greater than the front truncation delay. When the green split is greater than or equal to 0.64, the opposite is true. The phase difference of upstream and downstream intersections can be optimized and coordinated according to the goal that vehicles can smoothly pass through the coordinated control intersection or ensure the minimum delay, so as to give full play to the space-time utilization of the coordinated control intersection.

446 Relationship between out of hospital cardiac arrest and COVID-19 pandemic: impact on outcome

AimsDuring 2020, Italy was hit by the pandemic of the ‘Coronavirus disease 2019’ (COVID-19) with an incidence/100 000 citizens characterized by two peaks. An increase in out-of-hospital cardiac arrest (OHCA) mortality during the first pandemic peak has already been described, but there are few data on the whole year. The goal of our study is to evaluate the impact of the pandemic on post-OHCA mortality.MethodsWe considered patients with OHCA in Varese territory from January to December 2020 with medical aetiology according with Utstein 2014 classification. The primary endpoint of the study was the assessment of acute post-arrest mortality and which parameters influence this outcome. In particular, both the role of pandemic peaks (‘first peak’ from 11 March 2020 to 23rd May 2020 and ‘second peak’ from 7 October 2020 to 31 December 2020) and the average rescue times, i.e.: (i) interval between OHCA and call for first aid (delay in activation of assistance); (ii) the interval between the call and the arrival of the rescue vehicles (delay in the arrival of the first aid) and finally; (iii) the time between the arrival of the rescue vehicles and the end of Cardiopulmonary Resuscitation (CPR), interrupted due to death or Recovery of Spontaneous Circulation (ROSC). Finally, we performed a multivariate analysis to assess which of the variables considered had the greatest impact on the outcome.ResultsWe analysed 708 patients (mean age 76 + 14.09 years; 40% women). Overall mortality was 89%. During the peaks there was an increase in mortality compared to the pre-pandemic period (first peak 96% vs. 83%, OR 4.49; second peak 92% vs. 83%, OR 2.45) (Figure 1). The time between the collapse and the call for help was significantly higher during the first pandemic peak compared to the second peak and the pre-pandemic period (P = 0.003); the time between the call and the arrival on the patient was significantly longer during both pandemic peaks than in the previous period (P = 0.002) and there was no significant difference in CPR duration time between the periods analysed. In a multivariate model, the only time associated with an increase in mortality is the period between the call for help and the arrival on the patient, regardless of the COVID-19 pandemic.Figure 1446 ConclusionsDuring the COVID-19 pandemic there has been an increase in mortality of patients with OHCA. Among the variables considered, the increase in mortality is mainly associated with the delay in the arrival of emergency vehicles on site. This delay, although decreasing, was also maintained during the second peak of the pandemic.

Acceleration and Deceleration Rates of Various Vehicle Categories at Signalized Intersections in Mixed Traffic Conditions

The acceleration and deceleration rates vary from one vehicle type to another. The same vehicle type also exhibits variations in acceleration and deceleration rates due to vast variation in their dynamic and physical characteristics, ratio between weight and power, driver behaviour during acceleration and deceleration manoeuvres. Accurate estimation of acceleration and deceleration rates is very important for proper signal design to ensure minimum control delay for vehicles, which are passing through the intersection. The present study measures acceleration and deceleration rates for four vehicle categories: Two-wheeler, Three-wheeler, Car, and Light Commercial Vehicle (LCV), by using Open Street Map (OSM) tracker mobile application. The acceleration and deceleration rates were measured at 24 signalized intersection approaches in Hyderabad and Warangal cities. The study also developed acceleration and deceleration models for each vehicle type and the developed models were validated based on field data. The results showed that the predicted acceleration and deceleration models showed close relation with those measured in the field. The developed models are useful in predicting average acceleration and deceleration rate for different vehicle types under mixed and poor lane disciplined traffic conditions.

Signal Control Method for Through and Left-Turn Shared Lane by Setting Left-Turn Waiting Area at Signalized Intersections

This paper proposes a signal control method for the through and left-turn shared lanes at signalized intersections to solve traffic conflicts between left-turn vehicles and opposing through vehicles by setting left-turn waiting area (LWA). Delays and stops are weighted to form an integrated performance index (PI) in a vehicle-to-infrastructure cooperation system. The PI models pertaining to all vehicles are established based on the LWA intersection. In addition, an optimized method of signal timing parameters is constructed by minimizing the average PI. VISSIM simulation shows that the average PI decreases by 6.51% compared with the original layout and signal timing plan of the intersection, since the increased delay of the side-road left-turn vehicles is insufficient to offset the reduced delay of the side-road through vehicles after the improvement. The sensitivity analysis shows that the greater the traffic volume of the phase including the through and left-turn shared lanes, the higher the operation efficiency of the LWA intersection compared with the typical permitted phase intersection. When the left-turn vehicles of the shared lanes in each cycle are less than the stop spaces, the LWA intersection can effectively reduce the average PI of the shared lanes. Furthermore, the more the stop spaces in the LWA, the lower the average PI in the same traffic conditions.

Analyzing the delays of target lane vehicles caused by vehicle lane-changing operation

Vehicle lane-changing on urban roads is the most common traffic behavior, in which the driver changes the direction or increases the speed of the vehicle by changing its trajectory. However, in high-density traffic flow, when a vehicle changes lanes, a series of vehicles following the target vehicle in the target lane will be delayed. In this study, DJI Phantom 4 drones were used to vertically record the traffic on a road section. Tracker software was then used to extract vehicle information from the video taken by the drones, including the vehicle operating speeds, etc. SPSS 22 and Origin analysis software were then employed to analyze the correlations between different vehicle operating parameters. It was found that the operating speed of the first vehicle following the target vehicle in the target lane is related to the speeds and positions of both the target vehicle and the vehicle preceding it. Under the condition of high-density traffic flow, when the target vehicle is inserted into the target lane, the speed of the vehicles following the target vehicle in the target lane will change. To model this process, the corresponding Sine and DoseResp models were constructed. By calculating the delays of vehicles following the target vehicle in the target lane, it was concluded that the overall delay of the fleet is 3.9–9.5 s.

THE EFFECT OF SIDE FRICTION ON DELAYS IN ONE-WAY URBAN ROAD SECTIONS

The effect of side friction activities on delays due to the reduced free-flow speed was investigated by conducting a series of traffic surveys and referring to the 1997 Indonesian Highway Capacity Manual (IHCM) parameters. The movement of pedestrians, parking/stopping vehicles, vehicles entering and exiting the road, and the slow-and-stop motion of vehicles on the road sections was observed in video footage and analyzed to estimate the effect of side friction on the delays occurring. A weighting factor was used to determine the total value of side friction on the road to test the combined effect of all activities. This study used a regression model for estimating vehicle delays, as a performance parameter, on urban road sections, taking into account the effect of side friction on the road section's vehicle free-flow speed (FFS). It was found that vehicle speed decreased when side friction increased at all levels of traffic volume. Low side friction produced a higher vehicle free-flow speed (FFS), and analysis of the free-flow speed (FV) showed a lower vehicle free-flow speed (FFS) than that in the 1997 IHCM analysis. Delays at undersaturated inseparable one-way road sections (2/1 UD) with low to high side friction were described by the equation: Y = 0.002 X + 0.028 (R2 = 0.704) for Panca Usaha Road, and Y = 0.0022 X + 0.0104 (R2 = 0.774) for Pejanggik Road, where Y = Delay, X = Traffic Flow. The results of the above study indicate the existence of new performance parameters on urban road segment type 2/1 UD in the form of delay, and that can be an early indication as input in the update of IHCM 1997 and other research that the author has done before, as well as other authors who have also written about similar topics about this manual that is more than 20 years old (1997-2021), in analyzing the performance of road networks in Indonesia.

Vehicle Delay Model Applied to Dynamic and Static Traffic Impact Analysis of Large Parking Lots

With the surge of motor vehicle ownership and land intensification, plenty of large parking lots emerge as the times demand. Although it solves the problem of insufficient parking spaces, it intensifies the interaction between dynamic and static traffic. This paper presented an impact assessment method for the interaction of dynamic and static traffic flow in parking lots. Firstly, the average vehicle delay was selected as the evaluation index. The delay effect caused by the interaction of dynamic and static traffic flow was determined according to the driving path of vehicles. Then, the average vehicle delay models of arrival vehicles, departure vehicles, and road vehicles in the parking lot were established. Finally, for the parameters difficult to determine directly in the delay model, this paper proposed a method to calibrate the model parameters by using the simulation experimental data on the VISSIM platform. The results showed that the errors of the three models are within the controllable range, and the delay model parameters had high reliability and feasibility. The delay models can provide a quantitative basis for the parking lot management department to formulate regulation strategies and realize more refined information guidance and navigation in the parking lot.

Decentralized arterial traffic signal optimization with connected vehicle information

This paper proposes a decentralized signal control algorithm that leverages connected vehicle information to improve traffic operations along arterials. The proposed algorithm obtains real-time vehicle locations and speeds, as well as information on pedestrians waiting to cross individual intersections, to optimize signal phasing and timing plans. Signal timing is optimized at individual intersections; however, information about vehicle platoons passing a given intersection is shared with neighboring intersections to facilitate natural coordination between adjacent intersections. The decentralized algorithm is compared to a centralized algorithm that optimizes signal timing at all intersections simultaneously, as well as a traditional coordination strategy. The proposed algorithm is shown both to be more computationally efficient than the centralized approach and provide better operational performance (in terms of person, vehicle and pedestrian delay) than both the centralized algorithm and the traditional strategy. The algorithm is robust to a range of demand patterns and can be applied under scenarios in which not all vehicles are connected or full information about pedestrian arrivals is not available.

Use of Videography for Traffic Surveys in Sri Lanka

Traffic Surveys are crucial for different transport studies like Origin-Destination studies, Traffic Volume estimations, Vehicle Flow characteristics Determinations, Speed and Delay Studies, Turning Movement analysis, Parking Analysis etc. Currently, Sri Lankan researchers are using mostly human-based manual surveys and semi-automated methods for Traffic Surveys. However, there is an issue in cost, effort, the value of time, and the accuracy of data gathering in the above methods. Therefore, under Accelerating Higher Education Expansion and Development (AHEAD) grant, we are researching the possibility of doing surveys using videography and Artificial Intelligence technologies for continuous and accurate data collection to reduce the burden that is currently facing. Using CCTV video cameras, we have done surveys in different locations in Western Province to check

Real-time signal-vehicle coupled control: An application of connected vehicle data to improve intersection safety

The proliferation of Connected Vehicles and their ability to collect a large amount of data presents an opportunity for the real-time safety optimization of traffic networks. At intersections, Adaptive Traffic Signal Control (ATSC) systems and dynamic speed advisories are among the proactive real-time safety interventions that can assist in preventing rear-end collisions. This study proposes a Signal-Vehicle Coupled Control (SVCC) system incorporating ATSC and speed advisories to optimize safety in real-time. By applying a rule-based approach in conjunction with a Soft-Actor Critic RL framework, the system assigns speed advisories to platoons of vehicles on each approach and extends the current signal time accordingly. Dynamic traffic parameters are collected in real-time and are used to estimate the current conflict rate at the intersection, which is then used both as an input to the model and to evaluate performance. The system was tested on two different intersections modeled using real-world data through the simulation platform VISSIM. Traffic conflicts were reduced by 41–55%, and vehicle delay was reduced by 21–24%. The results also show that the system functions at lower levels of market penetration, with diminishing returns beyond 50% MPR. The proposed system presents an SVCC framework that is both effective and low in computational intensity to optimize safety at signalized intersections.

ANALISIS KINERJA SIMPANG BERSINYAL DAN BIAYA OPERASIONAL KENDARAAN PADA JALAN GALUNGGUNG – JALAN RAYA TIDAR – JALAN BONDOWOSO KOTA MALANG

Increased traffic flow at crossroads that doesn’t have a suitable infrastructure can cause traffic jam. The traffic jam that occurs also has an impact on vehicle operating cost that passing through the intersection. On the page malangchannel.com, the intersection at Jalan Galunggung, Jalan Raya Tidar and Jalan Bondowoso is one of the points in Malang City that have high frequently traffic jams. Congestion occurs because there are many motorized vehicles across to the area, where the area around the location has a shops, malls, campuses, and others. This study aims to find how much the intersection Level Of Service (LOS) and the vehicle operating costs that passing through the intersection and give the best solution in order to improve the performance of the intersection and reduce the vehicle operating cost. The data used include the geometric of intersection, traffic signals, side friction, traffic volume during peak hours, average speed of vehicles during peak hours and components of vehicle operating costs. The calculation of intersection performance using MKJI 1997, vehicle operating costs using Pacific Consultant International (PCI) and intersection congestion costs using Tzedakis 1980. The calculation results show that the existing condition of the intersection has passed the saturation point with the service level (LOS) F of and the average vehicle delay 1013.6 sec / pcu and the congestion cost Rp. 86,744,635 / hour for light vehicles (LV). and IDR 15,424,569 / hour for heavy vehicles (HV). Alternative improvements of intersection by resetting the phases from 2 to 4, road geometric adjustment and adding the flyovers, the congestion costs can be reduced to Rp. 1,319,498 / hour for light vehicles (LV) and Rp. 231,244 / hour for heavy vehicles (HV) with the Level Of Service (LOS) B from average delay of vehicle 14.5 sec / pcu.

Tandem Design of Bus Priority Based on a Pre-Signal System

Giving buses priority is an important measure to improve the attractiveness of public transport and to reduce urban traffic congestion. Reducing bus service delays as much as possible will have a positive impact on urban traffic. Based on the pre-signal system, a bus at an intersection with a left-turn special phase is optimized by “tandem design”. The design model is applied to the entrance of an intersection to study the process of vehicle arrival and departure at the main signal and pre-signal, and to calculate and analyze the delay changes of buses, straight social vehicles (meaning vehicles other than those required to be open to traffic) and left-turn vehicles before and after the adoption of “tandem design”. The results show that when the vehicle capacity at the intersection is saturated, the delays to buses and the delays of left-turn vehicles will be significantly reduced once the “tandem design” is adopted at the entrance of a cross intersection with a special left-turn phase. However, it has little effect on the delay of straight-on vehicles; with this system, the total delay experienced by straight vehicles will be reduced to one cycle.