This paper presents a novel approach to improve traffic throughput near diverge and weave bottlenecks in mixed traffic with human-driven vehicles (HDVs) and connected automated vehicles (CAVs). This is done by the strategic assignment of CAVs across lanes. The main principle is to induce strategic and necessary lane changes (LCs) (by CAVs and HDVs) well upstream of the potential bottleneck, so that the traffic flow approaching the bottleneck is organized and exhibits fewer throughput-reducing LCs at the bottleneck. A hybrid approach is used to investigate the problem: macroscopic analytical approach to formulate lane assignment strategies, and numerical simulations to quantify the improvements in throughput for various scenarios. Several strategies are formulated considering various operational conditions for each bottleneck type. Furthermore, compensatory behaviour of HDVs in response to the flow/density imbalance created by the CAV lane assignment is explicitly accounted for in our framework. Evaluation by numerical simulations demonstrates significant benefits of the proposed method, even at low to moderate CAV penetration rates: they can lead to an increase of throughput by several percent, thereby decreasing delays significantly.@en

For better and more efficient motorway traffic control strategies on a lane level, accurate modelling and prediction of traffic conditions is essential. Existing real-time traffic state estimation methods aggregate traffic across lanes. Hence, there is a need for lane-specific traffic flow models. The majority of the existing macroscopic lane-level traffic flow models use speed difference among lanes to explain lane change decisions. One of the major disadvantages of using speed difference as motivation for lane changing is the different speeds at which the lanes on a motorway operate. These models which are usually extensions of the Cell Transmission Model (CTM) also suffer in the manner in which lateral flow is transferred among cells in different lanes. In order to overcome these limitations, a model is proposed using density difference as an incentive to compute lane change rates rather than speed. A two-step transfer of lateral flow among cell segments is also considered where the lateral demand of a cell is dependent upon the receiving capacity of the adjacent and downstream cells in the target lane. The advantages of the presented approach is shown by comparing the proposed model with a conventional model. It was observed that the proposed model performed better in terms estimating densities across lanes. The proposed model is a step in the development of more accurate lane-specific traffic flow models.@en

Unbalanced lane usage on motorways might lead to the reduction in capacity of the motorway. Lane-level traffic management present new opportunities to balance the lane-flow distribution and help reduce congestion. In order to come up with efficient traffic management strategies on a lane-level, there is a need for accurate lane-specific traffic state estimation models. This paper presents a first-order lane-level traffic flow model. The proposed model differs from the existing models in the following areas: (i) incentive-based motivation for lane changes and consideration of downstream conditions (ii) transfer of lateral flows among cells. The model is tested against real-world data. It is observed that the model is able to capture the lane-level dynamics in terms of the lane flow distribution. The model results are compared to a linear regression model and results show that the developed model performs better than the regression model on the test sections.@en

Control measures at merging locations aimed at either the mainline traffic or on-ramp traffic do not lead to a fairness in the distribution of total delay across the two streams. This paper presents a control strategy of combining a lane change control with a ramp metering system at motorway merges. The control strategy presents the opportunity to control the delays incurred at the two traffic streams of the merge. An optimization problem is formulated for a multilane motorway with an on-ramp with the aim to minimize the total travel time of the system. The proposed strategy is tested using an incentive-based lane-specific traffic flow model. Results revealed a 17% reduction in the total travel time due to the proposed strategy. Moreover, it was shown that the distribution of delays over the mainline and on-ramp could be controlled via the proposed strategy. The performance of the combined control was also compared to the individual control measures. It was observed that the individual control measures (lane change only and ramp metering only) lead to high delays on either the mainline or on-ramp compared to the combined control, where the balance between the delay for the drivers on the mainline and on-ramp could be regulated. The combined lane change and ramp metering control presents opportunities for the road authorities to manage the total delay distribution across the two traffic streams.@en

Lane drops are a common bottleneck source on motorway networks. Congestion sets in upstream of a lane drop as a result of the lane changing activity of merging vehicles. This causes the queue discharge rate at the bottleneck to decrease and drop below the capacity, leading to capacity drop and further congestion. The objective of this study is to minimize the total travel time of the system by controlling lateral flows upstream of the lane drop. This is equivalent to maximizing the exit flows at the bottleneck. An optimization problem is formulated for a 3–2 lane drop section with high inflow. The problem is solved for different test cases where the direction of lateral flows being controlled is varied. An incentive based macroscopic model representing the natural lane changing scenario is used as a benchmark for comparison. The results showed that by influencing the lateral flows upstream of the bottleneck, the queue discharge rate increased by more than 4.5%. The total travel time of the system was consequently found to be reduced. The improvements in performance were primarily a result of the distribution of lane changing activity over space and the balancing of flow among the lanes which lead to the decrease in the severity of congestion. The findings reveal a potentially effective way to reduce the severity of congestion upstream of lane drop bottlenecks during high demand which could be implemented using roadside and in-car advisory systems.@en

Traffic congestion on motorways has become a common phenomenon across the world. Congestion on motorways is a major discomfort to road users and causes many problems such as reducing the capacity of the motorways, increasing travel times and fuel consumption leading to high economic and societal costs. Alleviating congestion and providing better mobility is one of the major problems facing transport engineers around the world. Traffic management and control aims to solve, reduce or at least postpone the problem of congestion. On multi-lane motorways, disproportionate usage of one or more lanes can lead to congestion setting in on heavily used lanes while spare capacity is still available on other lanes. Disproportionate lane flow distribution is usually a result of the lane changing behaviour of drivers. After the onset of congestion, the roadway capacity reduces by approximately 5-30%, a phenomenon known as capacity drop. While traffic flow theory and control is a well-established scientific discipline, traffic control applications have mostly been limited to the roadway level regardless of how the traffic is divided over the lanes. Thus, there is a need for the development of effective traffic control measures on multi-lane motorways which require the treatment of different lanes of a motorway as independent but interacting entities. This dissertation aims at making the step to lane-specific traffic control to mitigate the negative effects of lane changing on the traffic flow in multi-lane motorway bottlenecks. The main objective of this dissertation is to develop lateral control measures which influence the lane changing behaviour of traffic on motorways and evaluate their impact on traffic flow efficiency. The central research problem is addressed from two directions based on the composition of traffic. The impact of lateral control on traffic flow efficiency in homogenous traffic (where all vehicles in the traffic are assumed to have similar characteristics and behaviour) is firstly investigated. With advancements in automation and communication technologies, intelligent vehicles are slowly making their way on the roads and interacting with conventional traffic. This calls for the development and testing of modelling and control approaches that are robust to the different types of intelligent vehicles and their corresponding market penetration rates. Therefore, the impact of lateral control measures on traffic flow for a mixed traffic stream of human driven and intelligent vehicles is evaluated. A macroscopic approach describing aggregate flows is adopted to deal with homogenous traffic while a microscopic approach targeting individual vehicles is used for mixed traffic to account for the variation in traffic composition...@en

Merging areas are a common bottleneck source on motorways. In order to tackle congestion at these locations, efficient traffic management and control is vital to best utilize the available space. However, before the application of any traffic control measures, a thorough analysis of the effectiveness of the designed control action needs to be evaluated. The paper presents insights for the assessment of rule based traffic control at motorway merges. The methodology is then applied to a case study wherein an advisory system using rule based control for motorway merges considering mixed traffic is evaluated. With the aim to reduce travel times at merging sections, advices from the control system influencing the longitudinal behavior of mainline vehicles were generated. The advisory system was tested in a microsimulation tool for various penetration rates of controlled vehicles on the mainline. The effect of implementing the control action, side-effects of the design, risks involved and the overall role in improving or deteriorating the merging situation are then discussed. This can hence help in further developing any rule based control systems at motorway merges.@en