Transportation System Management and Operations Resources

**This resource has been updated to reflect the release of the 11th edition of MUTCD** Two-way separated bicycle lanes can be challenging to implement due to the many conflicting movements involved. A gated railroad grade crossing requires particularly high levels of care in handling crossing movements. Adding bicycle movements outside of the vehicle space can greatly increase the complexity.

This paper increases the awareness of cybersecurity threats targeted to critical infrastructure and the recognition of the transportation sector as critical by national security agencies such as the Department of Homeland Security.

The Institute of Transportation Engineers, on behalf of the Roadside Unit (RSU) Standardization Working Group is pleased to announce the publication of RSU Standard Version 1.0, also known as Connected Transportation Interoperability (CTI 4001 v01.00). The RSU Standard is a non-proprietary, technology neutral, industry-based consensus standard for roadside units, based on stakeholder inputs and existing resources such as the RSU Specification Version 4.1, NEMA's TS-10 Connected Vehicle Infrastructure – Roadside Equipment Standard as well as lessons learned from pilot deployments. The RSU Working Group accomplished this effort with broad stakeholder representation including standards development organizations (SDOs), infrastructure owner operators (IOOs), automotive original equipment manufacturers (OEMs) and suppliers, infrastructure equipment vendors, security specialists, Intelligent Transportation Systems (ITS) integrators, and end-users of data and services

The Institute of Transportation Engineers (ITE), on behalf of the Connected Intersections Project Committee, is pleased to announce the publication of the Connected Intersections (CI) Implementation Guide, known also as Connected Transportation Interoperability (CTI 4501 v01.00). This initial version of the CI Implementation Guide provides a detailed interface specification that can be used by the ITS community to deploy a nationally interoperable, openly available broadcast providing traffic Signal Phase and Timing and associated required mapping ("MAP") information that can be received by connected vehicles and other interested participants in the transportation system. This information enables applications such as Red Light Violation Warning and others that can increase both safety and efficiency. The Connected Intersections Project Committee accomplished this effort with broad stakeholder representation including standards development organizations , Intelligent Transportation Systems (ITS) infrastructure owner operators (IOOs), automotive original equipment manufacturers and suppliers, infrastructure equipment vendors, security specialists, ITS integrators, and end-users of data and services.

Convener: Eric Raamot, Econolite

Conveners: Bill Cisco and Jongsun Wun, PTV

Convener: Randy McCourt

Convener: Adam Hopps, NOCoE

Convener: Andrew Janzen, Street Simplified

Convener: Patrick Son, NOCoE

Convener: Pat Noyes, Pat Noyes & Associates

Convener: Abbas Mohaddes, Econolite

The critical distance is the foundation to Gazis, Herman and Maradudin's (GHM) universally adopted minimum yellow traffic signal timing solution presented in their 1960 paper, "The Problem of the Amber Signal Light in Traffic Flow" [1]. However, GHM's (permissive [2]) minimum yellow signal duration is limited in its application since they only accounted for vehicles moving at constant velocity traversing a minimum safe and comfortable stopping distance referenced a level intersection's stopping line, aka GHM's critical distance.

This discussion will review various models of drivers approaching an intersection in both through and turning lanes and what yellow change interval may be necessary in those situations. It is an extension of the work of Gazis, Herman, and Maradudin's (GHM) in their seminal 1960 paper, "The Problem of the Amber Signal Light in Traffic Flow". GHM proposed the basic protocol used today for setting a minimum yellow change interval for through movements that would provide a motorist with a solvable solution to the stop or go problem encountered when the yellow signal is illuminated.

Since the yellow indication was first added to traffic signals in 1920, the proper interval duration has been robustly debated.1 Seemingly, the timing of the yellow indication appears straightforward. However, determining the illumination interval is quite intricate since it is part of a complex system of physical and human-made laws, technology, and human behavior that all must operate compatibly.

Yellow change and red clearance intervals have been a topic of research for at least the last 60 years. It would be easy to assume that we now know all we need to know about the subject and that the remaining challenge is merely to put what we know into practice. But there is still much about driver behavior at intersections during traffic signal changes that we don't know with certainty or completely understand. During the development of the ITE Guidelines for Determining Traffic Signal Change and Clearance Intervals Recommended Practice, current knowledge, research, and practice in this area was documented, but the following 11 areas of interest were identified where additional study or new research is needed to expand the body of knowledge. Research in these areas would be useful in further refining the concepts and procedures in the ITE Recommended Practice.

ITE has concluded a years-long effort to issue guidance on yellow change and red clearance intervals for signalized intersections. The final version of the Recommended Practice Guidelines for Determining Traffic Signal Change and Clearance Intervals (RP-040B) has been adopted by the ITE International Board of Direction and is now available.1

The Institute of Transportation Engineers (ITE) has issued guidance on yellow change and red clearance intervals for signalized intersections. The recommended practice -- Guidelines for Determining Traffic Signal Change and Clearance Intervals -- has been adopted by the ITE International Board of Direction and is now available for purchase.

The population of Utah, USA is projected to nearly double by 2050. This projection presents a unique transportation challenge and stresses the need for innovation, collaboration, and long-range planning. In early 2017, the Utah Department of Transportation (UDOT) created a transportation technology engineer position to focus solely on connected vehicles, automated vehicles, and other traffic management technology projects. Building on the success of this role and the projects undertaken, UDOT created an entirely new group, recently renamed the IntelliMoveUtah group, to continue deploying these technologies. UDOT believes that new technologies, including connected and automated vehicles, will help address population growth and leverage this transformation in transportation in safer and more efficient ways.