Roads/Highways

This paper discusses the Freeway Service Patrol (FSP) Evaluation Project conducted under the California PATH program. The goal of this project was to determine the cost effectiveness of the FSP program along a 10-mile "beat" on I-880, near Hayward, California. The FSP is a group of tow trucks that drive around a particular section of the freeway during peak periods and provide free assistance to motorists with breakdowns or accidents. In the study section, there were usually two tow trucks that continuously drove around a 10 to 12-mile section of freeway. The hypothesis is that, since...

This paper presents the development of the Berkeley Highway Laboratory. The laboratory includes surveillance component, eight dual loop speed detector stations and 14 video cameras dedicated research, as well as an analytical component to advance traffic operations and traffic flow theory. The work builds on our experience with the I-880 field experiment and several other traffic studies. The lessons learned from the laboratory will be used to improve traffic surveillance and control, provide new traffic metrics, and enhance traffic models. This paper also presents correction factors that...

The performance of signalized arterials is related to queuing phenomena. The paper investigates the effect of transitional traffic flow conditions imposed by the formation and dissipation of queues. A cross-recurrence quantification analysis combined with Bayesian augmented networks are implemented to reveal the prevailing statistical characteristics of the short-term traffic flow patterns under the effect of transitional queue conditions. Results indicate that transitions between free-flow conditions, critical queue conditions that exceed the detector's length, as well as the occurrence...

The operation of freeway weaving sections is characterized by intense lane-changing maneuvers and complex vehicle interactions that often create bottlenecks along freeway facilities. The CORSIM microscopic simulation model was applied to simulate the operation of eight real-world weaving sites in California under a wide range of operating conditions. The results indicate that CORSIM with default parameter values underpredicts the speeds in the weaving section by about 19% on average. Numerous simulation runs were made with different values of the model parameters. The following parameters...