A ramp meter, ramp signal, or metering light is a device, usually a basic traffic light or a two-section signal light together with a signal controller, that regulates the flow of traffic entering freeways according to current traffic conditions. Ramp meters are used at freeway on-ramps to manage the rate of automobiles entering the freeway. Ramp metering systems have proved to be successful in decreasing traffic congestion and improving driver safety.
A pedestrian crossing or crosswalk is a place designated for pedestrians to cross a road, street or avenue. Pelican crosswalks are designed to keep pedestrians together where they can be seen by motorists, and where they can cross most safely across the flow of vehicular traffic.
The Manual on Uniform Traffic Control Devices (MUTCD) is a document issued by the Federal Highway Administration (FHWA) of the United States Department of Transportation (USDOT) to specify the standards by which traffic signs, road surface markings, and signals are designed, installed, and used. These specifications include the shapes, colors, and fonts used in road markings and signs. In the United States, all traffic control devices must legally conform to these standards. The manual is used by state and local agencies as well as private construction firms to ensure that the traffic control devices they use conform to the national standard. While some state agencies have developed their own sets of standards, including their own MUTCDs, these must substantially conform to the federal MUTCD.
A continuous flow intersection (CFI), also called a crossover displaced left-turn, is an alternative design for an at-grade road junction. Vehicles attempting to turn across the opposing direction of traffic cross before they enter the intersection. No left turn signal in the intersection is then necessary. Instead, vehicles traveling in both directions can proceed, including through vehicles and those turning right or left, when a generic traffic signal/stop sign permits.
Signal timing is the technique which traffic engineers use to distribute right-of-way at a signalized intersection. The process includes selecting appropriate values for timing which is implemented in specialized traffic signal controllers. Signal timing involves deciding how much green time the traffic signal provides to an intersection by movement or approach, how long the pedestrian WALK signal should be, whether trains or buses should be prioritized, and numerous other factors.
7F or 7-F can refer to:
Access management, Access control. When used in traffic and traffic engineering circles, this generally refers to the regulation of interchanges, intersections, driveways and median openings to a roadway. Its objectives are to enable access to land uses while maintaining roadway safety and mobility through controlling access location, design, spacing and operation. This is particularly important for major roadways intended to provide efficient service to through-traffic movements.
A quadrant roadway intersection adds an additional "quadrant roadway" between two legs of an intersection. This roadway adds two three-way intersections in addition to the original four-way intersection moving all left turns or right turns from the main intersection. The design is intended to improve traffic flow by reducing signal timing phases from four to two in the main intersection. The design is intended for intersections where large artery routes meet in an area of dense development and high pedestrian volume.
Intersection Capacity Utilization (ICU) method is a tool for measuring a roadway intersection's capacity. It is ideal for transportation planning applications such as roadway design, congestion management programs and traffic impact studies. It is not intended for traffic operations or signal timing design. ICU is also defined as "the sum of the ratios of approach volume divided by approach capacity for each leg of intersection which controls overall traffic signal timing plus an allowance for clearance times." The ICU tells how much reserve capacity is available or how much the intersection is overcapacity. The ICU does not predict delay, but it can be used to predict how often an intersection will experience congestion.
PTV Vissim is a microscopic multi-modal traffic flow simulation software package developed by PTV Planung Transport Verkehr AG in Karlsruhe, Germany. The name is derived from "Verkehr In Städten - SIMulationsmodell". PTV Vissim was first developed in 1992 and is today a global market leader.
Gordon Frank Newell was an American scientist, known for his contributions to applied mathematics, in particular traffic flow analysis and queueing theory. He authored over one hundred articles and wrote several books. The Gordon–Newell theorem is named after him and his colleague William J. Gordon.
A traffic count is a count of vehicular or pedestrian traffic, which is conducted along a particular road, path, or intersection. A traffic count is commonly undertaken either automatically, or manually by observers who visually count and record traffic on a hand-held electronic device or tally sheet. Traffic counts can be used by local councils to identify which routes are used most, and to either improve that road or provide an alternative if there is an excessive amount of traffic. Also, some geography fieldwork involves a traffic count. Traffic counts provide the source data used to calculate the Annual Average Daily Traffic (AADT), which is the common indicator used to represent traffic volume. Traffic counts are useful for comparing two or more roads, and can also be used alongside other methods to find out where the central business district (CBD) of a settlement is located. Traffic counts that include speeds are used in speed limit enforcement efforts, highlighting peak speeding periods to optimise speed camera use and educational efforts.
Traffic simulation or the simulation of transportation systems is the mathematical modeling of transportation systems through the application of computer software to better help plan, design, and operate transportation systems. Simulation of transportation systems started over forty years ago, and is an important area of discipline in traffic engineering and transportation planning today. Various national and local transportation agencies, academic institutions and consulting firms use simulation to aid in their management of transportation networks.
Paramics is traffic microsimulation software developed by Quadstone Paramics. Quadstone Paramics also develops pedestrian microsimulation software called the Urban Analytics Framework.
Cell Transmission Model (CTM) is a popular numerical method proposed by Carlos Daganzo to solve the kinematic wave equation. Lebacque later showed that CTM is the first order discrete Godunov approximation.
TSIS-CORSIM is a microscopic traffic simulation software package for signal systems, highway systems, freeway systems, or combined signal, highway and freeway systems. CORSIM consists of an integrated set of two microscopic simulation models that represent the entire traffic environment. NETSIM represents traffic on urban streets. FRESIM represents traffic on highways and freeways. Microscopic simulation models the movements of individual vehicles, which include the influences of geometric conditions, control conditions, and driver behavior. TSIS is an integrated development environment that enables users to conduct traffic operations analysis. Built using a component architecture, TSIS allows the user to customize the set of included tools, define and manage traffic analysis projects, define traffic networks and create inputs for traffic simulation analysis, execute traffic simulation models, and interpret the results of those models.
Sidra Intersection is a software package used for intersection (junction) and network capacity, level of service and performance analysis, and signalised intersection and network timing calculations by traffic design, operations and planning professionals.
MASSTR, the' Meadowlands Adaptive Signal System for Traffic Reduction, is an adaptive traffic control system commissioned by the New Jersey Meadowlands Commission (NJMC) for a forty square mile region in the New Jersey Meadowlands. Adaptive Signal Control Technology (ASCT) adjusts the signal timings based upon the flow of traffic instead of utilizing fixed or actuated timings. This regional intelligent transportation system (ITS) incorporates more than 128 traffic signals and serves more than 400,000 vehicles daily. MASSTR is one of a number of ITS projects deployed throughout New Jersey. MASSTR is the fourth-largest deployment of SCATS in the United States.
A split intersection is a rarely built at-grade variant of the diamond interchange. Compared to a conventional four-leg intersection or road crossing, the arterial road is split into separate carriageways by 200 to 300 feet, allowing a queue of left turning vehicles behind a completed turn into the crossroad without any conflict to oncoming traffic. On the crossroad, the four leg intersection is being replaced by two intersections. The beginning one-way traffic at the fourth leg makes the intersections reduce the number of conflicts similar to a three leg T-intersection to improve traffic flow.
TRANSYT is traffic engineering software developed by the Transport Research Laboratory. It is used to model signalised highway networks and has the ability to model platooning.