Traffic Operations and Management

The paper presents a microscopic asymmetric traffic flow theory based on detailed analysis of individual vehicle trajectories from the Next-Generation Simulation (NGSIM) database. The findings clearly show the asymmetry in vehicle’s acceleration and deceleration and define five traffic phases: free flow, acceleration, deceleration, coasting, and stationary. The proposed theory provides detailed description and mechanism of phase transitions. Extensions of the basic theory address common driver behavioral characteristics such as maneuvering error and anticipation. The application of the...

Many traffic control systems on urban arterials and grid networks include signals with actuated controllers. However, commonly used computer programs for signal timing cannot directly optimize the timing of coordinated signals. Users have to apply techniques designed for pretimed signals, and then "translate" the optimized pretimed settings into settings for the actuated controllers. In addition, other signal control choices, such as whether to operate a particular signal as pretimed, semi-actuated, or fully actuated, are left entirely to the user. This report describes the development of...

Based on current practices, traffic simulation models are calibrated and validated using macroscopic measures such as 15-minute averages of traffic counts or average point-to-point travel times. For an emerging number of applications, including connected vehicles, the realism of simulated driver dynamics at the second-by-second or subsecond trajectory level plays an important role. This report presents a Proof of Concept Application (PCA) for the Trajectory Level Validation Framework, which is presented in a separate report. The structure of this document parallels that of the Validation...

The Highway Capacity Manual is a major reference for evaluating the capacity and quality of service of road facilities. However, it holds the assumption that lanes perform equally, which can result in inaccuracies in performance estimation. The main purpose of this research is to develop a series of models for estimating flows and speeds by lane for various types of freeway segments, including basic, merge, and diverge types. These models consider the demand-to-capacity ratio, the presence of trucks, grade, and the presence of upstream and downstream ramps. To predict lane performance...