Canadian Capacity Guide For Signalized Intersections

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The Canadian Capacity Guide for Signalized Intersections (CCG) is a publication of the Canadian Institute of Transportation Engineers (CITE). [1] It provides a methodology that allows Traffic Engineers to plan, design, and evaluate traffic signal controlled roadway intersections.

Contents

The CCG has been based on the current experience of practicing traffic engineers, transportation educators and students across Canada, and a considerable body of Canadian and international research. But while developed in Canada, its methodology is applicable to conditions anywhere. The survey procedures included in the CCG provide direction for users in any country to collect local data which can be used to obtain geographically specific results.

Objectives

Many cities and metropolitan areas experience traffic congestion on some portions of their transportation networks. These municipalities also suffer from constrained urban space and limited financial resources, but they share the desire to improve the quality of their environment. The analytical tools to understand specific problems require refined methods for the evaluation of alternative solutions.

Techniques included in the CCG allow Traffic Engineers to analyze various situations and intersection configurations. This Guide emphasizes the importance of a clear definition of the objectives of signal operation at a specific location. It also provides an understanding of the role that the intersection plays in the travel patterns, public transportation, and both motorized and non-motorized modes of transportation.

The focus of the CCG is on the movement of traffic flow units, such as cars, trucks, transit vehicles, cyclists, and pedestrians at signalized intersections. The main parameter is the time dimension that determines how efficiently the available roadway space is used by conflicting traffic streams. The allocation of time to the movement of vehicular and pedestrian traffic in lanes and crosswalks influences not only intersection capacity, but also a number of other measures that describe the quality of service provided for the users. To this end, and to provide input to investigations of possible impacts, the Guide provides both analytical and evaluation methods, and a set of up-to-date numerical parameters for Canadian conditions.

Using the Guide, it is possible to assess a variety of solutions by application of a set of practical evaluation criteria. The evaluation criteria, or measures of effectiveness, provide the user with a comprehensive account of intersection operation. Two of the key measures of effectiveness are total person delay and delay to pedestrians. These criteria are essential as the prerequisites for an equitable treatment of all modes of transportation, especially public transit. Other performance measures relate the Guide to environmental, economic and safety analyses, and serve as vital information for transportation demand modelling.

Delay and the ratio of volume to capacity are two key parameters widely used in the profession to assess the performance of an intersection. The Guide focuses on the ratio of volume to capacity as a rational measure of how well the intersection is accommodating demand, but it is acknowledged that delay is also widely used (for example, in the Highway Capacity Manual). Whether one parameter or the other is the most relevant is the subject of ongoing debate in the profession. It is advisable to consider both parameters in the assessment of an intersection, at the level of the individual movement, the approach and the intersection as a whole.

Scope

The Guide provides a set of techniques that can be applied to operational, design and planning problems at signalized intersections. The operational procedures deal with a detailed assessment of operating conditions within a relatively short time frame when all factors are known or can be reasonably estimated. The design process is used to determine specific control parameters and geometric features of an intersection that will meet desired design objectives and performance criteria. Planning techniques, often called functional design, are useful for longer range problems, assisting in the determination of the type of the facility and its basic dimensions. The basic method remains the same for all three application types, but the level of detail varies.

Wherever possible, the Guide utilizes formula-oriented techniques that can be applied both in manual calculations and computer programs, including spreadsheet tables. Although advanced simulation and other computerized techniques may prove to be superior to formula based methods in the future, the understanding of the fundamentals contained in the Guide remains essential.

Where practical, measured input parameters and measured output performance criteria are preferable to calculated values. Correct and consistent survey methods as well as a critical assessment of the degree of precision and reliability of the survey results are essential.

The principles and components of the timing design and evaluation processes are based on the international state-of-the-art in both the research and practice for intersection control. As a consequence, a knowledgeable user will find many similarities to other international documents. Nevertheless, some individual procedures, especially with respect to saturation flow and evaluation criteria, may differ because they were developed, tested, or adjusted for specific Canadian conditions. Some methods and parameter values are a direct result of the work on this Edition, but wherever possible, the original references or sources are identified. The Guide allows the evaluation of existing or future intersection control or geometric conditions relative to travel demand. It does not deal directly with broad systems or network issues, such as transportation demand management or congestion management. The results of the procedures included in the Guide, however, can be used as information for the evaluation of the impact of intersection control, or geometric alternatives on system aspects, such as population mobility, accessibility of various destinations or land use strategies. Although safety is an integral part of all traffic considerations, the Guide does not address this broad and complex issue explicitly. It is left to other specialized documents.

Third Edition (2008)

Similar to the First Edition, the new Third Edition of the Guide concentrates mostly on urban applications. Although the procedures focus on fixed-time signal operation, advice is provided for their adjustment to the design and evaluation of traffic responsive signal control, including the traffic actuated method. The objectives of the current 3rd edition of the Guide were as follows:

CITE & ITE

The Canadian Capacity Guide for Signalized Intersections has been developed as a special project of the Canadian Institute of Transportation Engineers or CITE. This organization is composed of more than 1,700 transportation engineers, planners, technologists and students across Canada. [2]

CITE comprises District 7 of the Institute of Transportation Engineers, which consists of transportation professionals in more than 70 countries who are responsible for the safe and efficient movement of people and goods on streets, highways and transit systems. [3]

Software Tools

The CITE has sanctioned the development of a 3rd party software solution, InterCalc, that fully supports the CCG methodology. [4] In addition, PTV Vistro, developed by PTV Group, has integrated the Canadian Capacity Guide (CCG) methods into the software since the release of Version 6. This integration allows users to analyze small to large signalized urban networks in a modern traffic analysis software platform. [5]

Related Research Articles

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Roundabout Traffic intersection

A roundabout is a type of circular intersection or junction in which road traffic is permitted to flow in one direction around a central island, and priority is typically given to traffic already in the junction.

Traffic engineering (transportation)

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Level of service (LOS) is a qualitative measure used to relate the quality of motor vehicle traffic service. LOS is used to analyze roadways and intersections by categorizing traffic flow and assigning quality levels of traffic based on performance measure like vehicle speed, density, congestion, etc. In a more general sense, levels of service can apply to all services in asset management domain.

Reliability engineering is a sub-discipline of systems engineering that emphasizes the ability of equipment to function without failure. Reliability describes the ability of a system or component to function under stated conditions for a specified period of time. Reliability is closely related to availability, which is typically described as the ability of a component or system to function at a specified moment or interval of time.

Diverging diamond interchange Freeway interchange design

A diverging diamond interchange (DDI), also called a double crossover diamond interchange (DCD), is a subset of diamond interchange in which the opposing directions of travel on the non-freeway road cross each other on either side of the interchange so that traffic crossing the freeway on the overpass or underpass is operating on the opposite driving side from that which is customary for the jurisdiction. The crossovers may employ one-side overpasses or be at-grade and controlled by traffic light.

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 are implemented in specialized traffic signal controllers. Signal timing involves deciding how much green time the traffic signal provides 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.

In mathematics and transportation engineering, traffic flow is the study of interactions between travellers and infrastructure, with the aim of understanding and developing an optimal transport network with efficient movement of traffic and minimal traffic congestion problems.

Microsimulation is a category of computerized analytical tools that perform highly detailed analysis of activities such as highway traffic flowing through an intersection, financial transactions, or pathogens spreading disease through a population. Microsimulation is often used to evaluate the effects of proposed interventions before they are implemented in the real world. For example, a traffic microsimulation model could be used to evaluate the effectiveness of lengthening a turn lane at an intersection, and thus help decide whether it is worth spending money on actually lengthening the lane.

A junction is where two or more roads meet.

STREAMS Integrated Intelligent Transport System is an enterprise traffic management system designed to operate in the Microsoft Windows environment. Like most traffic management systems, STREAMS is an array of institutional, human, hardware, and software components designed to monitor, control, and manage traffic on streets and highways. Advanced traffic management systems come under the banner of ITS. ITS is the application of information and communications technology to transport operations in order to "reduce operating costs", "improve safety" and "maximize the capacity of existing infrastructure". STREAMS provides traffic signal management, incident management, motorway management, vehicle priority, traveler information, flood monitoring and parking guidance within a single integrated system is what the product says. STREAMS is developed by Transmax.

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Traffic light control and coordination

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The Bridge Software Institute is headquartered at the University of Florida (UF) in Gainesville, Florida. It was established in January 2000 to oversee the development of bridge related software products at UF. Today, Bridge Software Institute has a leadership position in the bridge software industry and Bridge Software Institute products are used by engineers nationwide, both in state Departments of Transportation and leading private consulting firms. Bridge Software Institute software is also used for the analysis of bridges in various countries by engineers around the world.

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Cycling infrastructure Facilities for use by cyclists

Cycling infrastructure refers to all infrastructure permissible for use by cyclists, including the network of roads and streets used by motorists, except where cyclists are excluded, along with bikeways from which motor vehicles are excluded—including bike paths, bike lanes, cycle tracks, rail trails and, where permitted, sidewalks. Cycling infrastructure also includes amenities such as bike racks for parking, shelters, service centers and specialized traffic signs and signals. Cycling modal share is strongly associated with the size of local cycling infrastructure.

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.

Junctions (software)

Junctions is a software package by Transport Research Laboratory. It incorporates the previously separate programs ARCADY, PICADY and OSCADY. The latest version, Junctions 10, was launched Wednesday 3 February 2021.

References

  1. "Canadian Institute of Transportation Engineers". Archived from the original on 2009-11-10. Retrieved 2009-12-07.
  2. "Canadian Institute of Transportation Engineers". Archived from the original on 2009-11-10. Retrieved 2009-12-07.
  3. "Home". ite.org.
  4. "InterCalc - BA Group Transportation Consultants". Archived from the original on 2010-05-15. Retrieved 2009-12-08.
  5. "PTV Vistro new". 26 January 2021.