Measurements taken downstream of freeway/on-ramp merges have verified that discharge flow diminishes when a merge becomes an active bottleneck. We show that metering the on-ramp can recover the higher discharge flow and thereby increase merge capacity. Detailed observations collected using video revealed that the outflow drop following activation was triggered by a queue that formed near the me...

A new ramp metering strategy implemented on the Twin Cities freeway system to reduce ramp waiting times was evaluated through microsimulation of freeway activity. The study compared Stratified Ramp Metering strategy with the previous Zone Metering Strategy and with no control strategy. Comparison with Zone, which was designed to favor freeway flow, showed the new strategy succeeded in greatly r...

existence of capacity drop phenomenon, as the difference between pre-queue and queue discharge flow rates, has been one of the controversial concepts of traffic engineering. several researches have focused on capacity drop existence and also its estimation issues. this paper aims to estimate capacity drop based not only on a comparison between breakdown and queue discharge flow rates, but also ...

Bottlenecks are key features of any freeway system and represent the emerging location for recurrent and non-recurrent traffic congestion. In Oregon, a freeway data archive known as PORTAL records volume, occupancy, and speed measurements from over 600 freeway locations every 20 seconds. This archive has enabled development of online freeway performance and reliability analysis tools. This pape...

An efficient freeway system will be essential to the development of Africa, and interchanges are a key to that efficiency. Around the world, many interchanges between freeways and surface streets, called service interchanges, are of the diamond configuration, and interchanges using roundabouts or loop ramps are also popular. However, many diamond interchanges have serious operational problems, ...

This study presents an integrated model and its solution algorithm for freeway corridor control during incident management. With a parallel arterial as the detour route, the proposed model aims to produce the optimal diversion rates from the freeway mainline to relieve the congestion at the incident segment, and concurrently adjust signal timings at the arterial intersections to best accommodat...

The paper characterizes the behavior of the cell transmissionmodel of a freeway, divided intoN sections or cells, each with one on-ramp and one off-ramp. The state of the dynamical system is theN-dimensional vector n of vehicle densities in theN sections. A feasible stationary demand pattern induces a unique equilibrium flow in each section. However, there is an infinite set—in fact a continuum...

1 a typical simple one-side weaving section, as shown in Figure 1, the geometric variables of the weaving section are the length of the weaving section, L, and the number of lanes within the weaving section, N. Length of the weaving section is measured from a point where the entrance gore is 2 feet wide to a point where the exit gore is 12 feet wide. Vehicular flow is categorized into four gene...

An integrated modeling of freeway traffic is developed, whose implementation in an uniform computer–aided simulation model facilitate comparative evaluation and systematic coupling of several traffic simulations, traffic controls, traffic measurements and traffic scenarios. The integrated modeling of freeway traffic is a basic mapping of freeway networks, control methods, measurements and diffe...