Traffic engineering (transportation)

Traffic engineering is a branch of civil engineering that uses engineering techniques to achieve the safe and efficient movement of people and goods on roadways. It focuses mainly on research for safe and efficient traffic flow, such as road geometry, sidewalks and crosswalks, cycling infrastructure, traffic signs, road surface markings and traffic lights. Traffic engineering deals with the functional part of transportation system, except the infrastructures provided.

Traffic engineering is closely associated with other disciplines:

Typical traffic engineering projects involve designing traffic control device installations and modifications, including traffic signals, signs, and pavement markings. Examples of Engineering Plans include pole engineering analysis and Storm Water Prevention Programs (SWPP).[1] However, traffic engineers also consider traffic safety by investigating locations with high crash rates and developing countermeasures to reduce crashes. Traffic flow management can be short-term (preparing construction traffic control plans, including detour plans for pedestrian and vehicular traffic) or long-term (estimating the impacts of proposed commercial/residential developments on traffic patterns). Increasingly, traffic problems are being addressed by developing systems for intelligent transportation systems, often in conjunction with other engineering disciplines, such as computer engineering and electrical engineering.

Makati intersection
Complex intersections with multiple vehicle lanes, bike lanes, and crosswalks are common examples of traffic engineering projects

Traffic systems

Traditionally, road improvements have consisted mainly of building additional infrastructure. However, dynamic elements are now being introduced into road traffic management. Dynamic elements have long been used in rail transport. These include sensors to measure traffic flows and automatic, interconnected, guidance systems to manage traffic (for example, traffic signs which open a lane in different directions depending on the time of day). Also, traffic flow and speed sensors are used to detect problems and alert operators, so that the cause of the congestion can be determined, and measures can be taken to minimize delays. These systems are collectively called intelligent transportation systems.

Lane flow equation

Ramp meter from Miller Park Way to I-94 east in Milwaukee
A ramp meter limits the rate at which vehicles can enter the freeway

The relationship between lane flow (Q, vehicles per hour), space mean speed (V, kilometers per hour) and density (K, vehicles per kilometer) is

Observation on limited access facilities suggests that up to a maximum flow, speed does not decline while density increases. However, above a critical threshold, increased density reduces speed. Additionally, beyond a further threshold, increased density reduces flow as well.

Therefore, speeds and lane flows at bottlenecks can be kept high during peak periods by managing traffic density using devices that limit the rate at which vehicles can enter the highway. Ramp meters, signals on entrance ramps that control the rate at which vehicles are allowed to enter the mainline facility, provide this function (at the expense of increased delay for those waiting at the ramps).

Highway safety

Highway safety engineering is a branch of traffic engineering that deals with reducing the frequency and severity of crashes. It uses physics and vehicle dynamics, as well as road user psychology and human factors engineering, to reduce the influence of factors that contribute to crashes. A well-drafted Traffic Control Plan (TCP) is critical to any job involving roadway work. A properly-prepared TCP will specify equipment, signage, placement, and personnel.[2]

A typical traffic safety investigation follows these steps [3]

1. Identify and prioritize investigation locations. Locations are selected by looking for sites with higher than average crash rates, and to address citizen complaints.
2. Gather data. This includes obtaining police reports of crashes, observing road user behavior, and collecting information on traffic signs, road surface markings, traffic lights and road geometry.
3. Analyze data. Look for collisions patterns or road conditions that may be contributing to the problem.
4. Identify possible countermeasures to reduce the severity or frequency of crashes.
• Evaluate cost/benefit ratios of the alternatives
• Consider whether a proposed improvement will solve the problem, or cause "crash migration." For example, preventing left turns at one intersection may eliminate left turn crashes at that location, only to increase them a block away.
• Are any disadvantages of proposed improvements likely to be worse than the problem you are trying to solve?
5. Implement improvements.
6. Evaluate results. Usually, this occurs some time after the implementation. Have the severity and frequency of crashes been reduced to an acceptable level? If not, return to step 2.

See also

References

  1. ^ City Rise Safety Engineering Plans and why they matter..
  2. ^ Traffic Control Plans What Traffic Control Plans do to keep you community safe.
  3. ^ Road Safety Fundamentals. Ithaca, NY: Cornell Local Roads Program. September 2009.
  • Homburger, Kell and Perkins, Fundamentals of Traffic Engineering, 13th Edition, Institute of Transportation Studies, University of California (Berkeley [1]), 1992.
  • Das, Shantanu and Levinson, D. (2004) A Queuing and Statistical Analysis of Freeway Bottleneck Formation. ASCE Journal of Transportation Engineering Vol. 130, No. 6, November/December 2004, pp. 787–795
Bus priority

Bus priority or transit signal priority (TSP) is a name for various techniques to improve service and reduce delay for mass transit vehicles at intersections (or junctions) controlled by traffic signals. TSP techniques are most commonly associated with buses, but can also be used along tram/streetcar or light rail lines, especially those that mix with or conflict with general vehicular traffic.

Bus rapid transit

Bus rapid transit (BRT), also called a busway or transitway, is a bus-based public transport system designed to improve capacity and reliability relative to a conventional bus system. Typically, a BRT system includes roadways that are dedicated to buses, and gives priority to buses at intersections where buses may interact with other traffic; alongside design features to reduce delays caused by passengers boarding or leaving buses, or purchasing fares. BRT aims to combine the capacity and speed of a metro with the flexibility, lower cost and simplicity of a bus system.

The first BRT system was the Rede Integrada de Transporte ('Integrated Transportation Network') in Curitiba, Brazil, which entered service in 1974.

As of March 2018, a total of 166 cities in six continents have implemented BRT systems, accounting for 4,906 km (3,048 mi) of BRT lanes and about 32.2 million passengers every day, of which about 19.6 million passengers ride daily in Latin America, which has the most cities with BRT systems, with 54, led by Brazil with 21 cities. The Latin American countries with the most daily ridership are Brazil (10.7M), Colombia (3.06M), and Mexico (2.5M). In the other regions, China (4.3M) and Iran (2.1M) also stand out. Currently, TransJakarta is considered as the largest BRT network in the world with approximately 251.2 kilometres (156.1 mi) of corridors connecting the Indonesian capital city.

Creighton Manning Engineering

Creighton Manning Engineering, LLP is a multi-discipline civil engineering and surveying firm located in Albany, New York. The firm has been in business since 1965.

Creighton Manning Engineering claims to be one of the top 10 civil engineering firms in the Capital District. Creighton Manning Engineering was recently recognized as "One of the Great Places to Work in the Capital Region" through an independent survey conducted for the Business Review.As of 2012, Creighton Manning has approximately 55 employees. Employees are of the following positions: project manager, civil engineer, surveyor, construction inspector and CAD drafters. Many of the firms engineers are professionally licensed as Professional Engineer.

GEH statistic

The GEH Statistic is a formula used in traffic engineering, traffic forecasting, and traffic modelling to compare two sets of traffic volumes. The GEH formula gets its name from Geoffrey E. Havers, who invented it in the 1970s while working as a transport planner in London, England. Although its mathematical form is similar to a chi-squared test, is not a true statistical test. Rather, it is an empirical formula that has proven useful for a variety of traffic analysis purposes.

The formula for the "GEH Statistic" is:
Where M is the hourly traffic volume from the traffic model (or new count) and C is the real-world hourly traffic count (or the old count)

Using the GEH Statistic avoids some pitfalls that occur when using simple percentages to compare two sets of volumes. This is because the traffic volumes in real-world transportation systems vary over a wide range. For example, the mainline of a freeway/motorway might carry 5000 vehicles per hour, while one of the on-ramps leading to the freeway might carry only 50 vehicles per hour (in that situation it would not be possible to select a single percentage of variation that is acceptable for both volumes). The GEH statistic reduces this problem; because the GEH statistic is non-linear, a single acceptance threshold based on GEH can be used over a fairly wide range of traffic volumes. The use of GEH as an acceptance criterion for travel demand forecasting models is recognised in the UK Highways Agency's Design Manual for Roads and Bridges the Wisconsin microsimulation modeling guidelines, the Transport for London Traffic Modelling Guidelines and other references.

For traffic modelling work in the "baseline" scenario, a GEH of less than 5.0 is considered a good match between the modelled and observed hourly volumes (flows of longer or shorter durations should be converted to hourly equivalents to use these thresholds). According to DMRB, 85% of the volumes in a traffic model should have a GEH less than 5.0. GEHs in the range of 5.0 to 10.0 may warrant investigation. If the GEH is greater than 10.0, there is a high probability that there is a problem with either the travel demand model or the data (this could be something as simple as a data entry error, or as complicated as a serious model calibration problem).

Kerner's breakdown minimization principle

Kerner’s breakdown minimization principle (BM principle) is a principle for the optimization of vehicular traffic networks introduced by Boris Kerner in 2011.

Michael Horodniceanu

Michael Horodniceanu (born Mihai Horodniceanu; August 4, 1944) is a Romanian American engineer. He was president of MTA Capital Construction. He was born in Bucharest, Romania, and emigrated to Israel at age 16. He served in the military there and graduated Technion. In 1970 he came to the U.S. with his family. He founded the Urbitran Group in 1973, being CEO from 1980 to 1986 and 1990 to 2008. From 1986 to 1990 he was traffic commissioner in New York City. He taught transportation planning, highway design, traffic engineering, transportation financing, and system safety as a full-time professor in both the undergraduate and graduate schools of Polytechnic Institute of New York University (NYU-POLY) and Manhattan College. He earned a Ph.D. in Transportation Planning & Engineering from Polytechnic Institute of New York University (NYU-POLY). He is a former engineer-in-chief of the MTA.

Outline of engineering

The following outline is provided as an overview of and topical guide to engineering:

Engineering is the scientific discipline and profession that applies scientific theories, mathematical methods, and empirical evidence to design, create, and analyze technological solutions cognizant of safety, human factors, physical laws, regulations, practicality, and cost.

Outline of transport

The following outline is provided as an overview of and topical guide to transport:

Transport or transportation – movement of people and goods from one place to another.

Solomon curve

The Solomon curve is a graphical representation of the collision rate of automobiles as a function of their speed compared to the average vehicle speed on the same road. The curve was based on research conducted by David Solomon in the late 1950s and published in 1964. Subsequent research suggests significant biases in the Solomon study, which may cast doubt on its findings.

Traffic engineering

Traffic engineering can mean:

Traffic engineering (transportation), a branch of civil engineering

Teletraffic engineering, a field of statistical techniques used in telecommunications

Web navigation

Web navigation refers to the process of navigating a network of information resources in the World Wide Web, which is organized as hypertext or hypermedia. The user interface that is used to do so is called a web browser.A central theme in web design is the development of a web navigation interface that maximizes usability.

A website overall navigational scheme includes several navigational pieces such as global, local, supplemental, and contextual navigation; all of these are vital aspects of the broad topic of web navigation. Hierarchical navigation systems are vital as well since it is the primary navigation system. It allows for the user to navigate within the site using levels alone, which is often seen as restricting and requires additional navigation systems to better structure the website. The global navigation of a website, as another segment of web navigation, serves as the outline and template in order to achieve an easy maneuver for the users accessing the site, while local navigation is often used to help the users within a specific section of the site. All these navigational pieces fall under the categories of various types of web navigation, allowing for further development and for more efficient experiences upon visiting a webpage.

Languages

This page is based on a Wikipedia article written by authors (here).
Text is available under the CC BY-SA 3.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.