Spanwise forcing for turbulent drag reduction: An experimental investigation into active and passive flow control

Turbulent drag reduction (DR) is a crucial research area, as this can contribute to significant energy and emission reductions in various industrial and transportation applications. One such technique is the active flow control method of spanwise forcing. Spanwise forcing introduces a spatio-temporal spanwise wall oscillation as a boundary...

Microscopic Traffic Modeling Inside Intersections: Interactions Between Drivers

Microscopic traffic flow models enable predictions of traffic operations, which allows traffic engineers to assess the efficiency and safety effects of roadway designs. Modeling vehicle trajectories inside intersections is challenging because there is an infinite number of possible paths in a two-dimensional space, and drivers can...

Ramp Metering with Microscopic Gap Detection Algorithm Design and Empirical Acceleration Verification

Freeway on-ramp areas are susceptible to traffic congestion during peak hours. To delay or prevent the onset of congestion, ramp metering can be applied. A Ramp Metering Installation (RMI) controls the inflow from the on-ramp to the main line so that the total flow can be kept just below capacity. Current ramp metering algorithms apply...

Optimizing distribution of metered traffic flow in perimeter control: Queue and delay balancing approaches

Perimeter traffic flow control based on the macroscopic or network fundamental diagram provides the opportunity of operating an urban traffic network at its capacity. Because perimeter control operates on the basis of restricting inflow via reduced green times at selected entry (gated) links, vehicles on those links may be subject to queuing and...

Robust Signal Control of Exit Lanes for Left-Turn Intersections with the Consideration of Traffic Fluctuation

Traffic throughput at intersections can be improved by using exit lanes for left-turning (EFL), tidal flow lanes near an intersection, which has been recently introduced. This paper considers the operational robustness of the EFL intersection in relation to the control scheme applied to the traffic light setting. For safety and efficiency, it...

Two-dimensional vehicular movement modelling at intersections based on optimal control

Modeling traffic flow at intersections is essential for the design, control, and management of intersections. A challenging feature of microscopic modeling vehicular movement at intersections is that drivers can choose among an infinite number of alternative traveling paths and speeds. This makes it fundamentally different from structured...

Departure rates optimization and perimeter control: Comparison and cooperation in a multi-region urban network

With the renewed interest in the Macroscopic Fundamental Diagram (MFD) in the last decade, studies on network-level urban traffic control have increased in popularity. A popular urban traffic control approach is perimeter control, in which vehicle accumulation is kept below some critical accumulation value. An alternative control strategy is to...

Ramp Metering with Real-Time Estimation of Parameters

Demand exceeding the capacity of a bottleneck will create congestion upstream of that bottleneck. Once this congestion occurs, the maximum flow through this bottleneck decreases (capacity drop). By limiting the flow towards the bottleneck, one can prevent or postpone the capacity drop and the accompanying congestion. In case the bottleneck is...

Using advanced adaptive cruise control systems to reduce congestion at sags: An evaluation based on microscopic traffic simulation

Sags are roadway sections along which the gradient increases gradually in the direction of traffic. Sags are generally bottlenecks in freeway networks. Previous research suggests that traffic management measures using advanced Adaptive Cruise Control (ACC) systems could reduce congestion on freeways, but little is known about their potential...

Traffic-responsive signals combined with perimeter control: investigating the benefits

Empirical and research evidence suggests that traffic-responsive signal control strategies are generally not as efficient in over-saturated traffic conditions characterized by queue spillbacks. Recent studies on (MFD/NFD) have identified a destabilizing gridlock process that arises in congested networks which precludes efficient operation. The...

Strategy-Based Driving Behaviour on Freeways: Findings of Test-Drive and On-Line Survey Study

Freeways form an important part of the road network. Drivers’ behavior can be split in longitudinal (acceleration and deceleration) and lateral behavior (lane changing). The combination of these two behaviors on freeways play a key role in traffic operations. This paper tries to describe the driving behavior, emphasizing the relation between the...

Combination of traffic-responsive and gating control in urban networks: Effective interactions

Recent findings regarding macroscopic relationships of urban traffic measures such as the Macroscopic or Network Fundamental Diagram (MFD or NFD) have led to the development of novel traffic control strategies that can be applied at a network-wide level. One pertinent example is perimeter flow control (also known as gating or metering), which...

Optimization of traffic flow at freeway sags by controlling the acceleration of vehicles equipped with in-car systems

Sags are bottlenecks in freeway networks. According to previous research, the main cause is that most drivers do not accelerate enough at sags. Consequently, they keep longer headways than expected given their speed, which leads to congestion in high demand conditions. Nowadays, there is growing interest in the development of traffic control...

Comparison of On-Line Time-Delayed and Non-Time-Delayed Urban Traffic Control via Remote Gating

Recent studies demonstrated the efficiency of feedback-based gating control in mitigating congestion in urban networks by exploiting the notion of network fundamental diagram (NFD). The employed feedback regulator of proportional-integral(PI)-type targets an operating NFD point of maximum throughput to enhance the mobility in the urban road...