ADOPTED APRIL 2012

Southern California Association of Governments

INTELLIGENT TRANSPORTATION

SYSTEMS APPENDIX
INTELLIGENT TRANSPORTATION SYSTEMS

Introduction 1

Existing System Description 1

Existing System Performance and Operational Impacts from ITS 2

Future Baseline System Improvements 3

Recommended Policies and Actions 3
Introduction

Intelligent Transportation Systems (ITS) make use of advanced detection, communications, and computing technology to improve the safety and efficiency of our surface 

transportation network. ITS is a program of technology applications and integration that 

allows system operators and users to better manage and optimize the use of transportation system capacity. ITS allows for the use of information technologies to collect data 

about the status of our highways, traffic signals, transit vehicles, trucks and trains, and 

integrates that data in ways that affect and improve the efficiency of the system.

ITS systems are not new to the SCAG region. Systems like the City of Los Angeles 

Automated Traffic Surveillance and Control (ATSAC) computer-based signal system have 

been in place since first installed around the LA Coliseum for the 1984 Olympics. This 

assists in optimizing signal timing to accommodate varying traffic demands throughout the day. Beginning in the 1990’s, Rapid Bus ITS systems have been installed using 

technology to prioritize transit movements through signalized intersections. These 

technologies have grown to track buses, provide motorists and transit users “real-time” 

information, and manage natural and manmade disasters in state of the art Traffic 

Management Centers.

Existing System Description

The freeways system in Southern California have an extensive freeway detection system 

covering much of the urbanized portion of the system. Loop detectors in the pavement 

and video cameras provide information on speed and volume, and identify congestion 

and incidents which are fed to Caltrans/California Highway Patrol (CHP) Transportation 

Management Centers (TMC’s). The TMC’s are manned 24/7 by CHP and Caltrans personnel, and monitor and respond to changes in traffic conditions, including both planned 

events and emergencies. Information is conveyed to the public through traditional media, 

advanced media (the Internet, PDA’s), and through changeable message signs on our 

Freeways. These capabilities allow Caltrans to respond quickly to incidents and allow the 

public to adjust their travel plans.

Arterial ITS systems are in place throughout the SCAG Region; local arterial systems 

include advanced signal synchronization capabilities and the ability to detect and respond 

to changes in traffic volume or direction of travel, or incidents. Some arterial ITS systems 

include bus prioritization for the operation of Rapid Bus transit operations. Many local 

arterial ITS systems include high level video detection to observe traffic conditions and 

incidents. Local ITS systems also include information components such as changeable 

message signs and highway advisory radio channels to convey information to users during 

events or emergencies.

Transit ITS systems include automatic vehicle location (AVL) systems that detect bus 

locations, heading, speed, and time of arrival. AVL systems allow for the monitoring of 

bus performance, improved safety and security, and enhanced customer information 

such as “real-time” scheduling. AVL systems are often used in conjunction with bus 

priority signal systems to improve running times and reduce delays, and are an integral 

component of most of the Rapid Bus systems. Bus Transit ITS also includes advanced 

passenger counting systems and electronic fare systems that improve operations, reduce 

fraud and fare evasion, and collect data to better understand system performance and 

plan more effective operations. Such systems also allow for more effective use of transit 

systems in response to emergencies to assist in the evacuation of impacted areas. Today, 

AVL Transit systems are widely deployed, including on most of the buses of LACMTA, 

Long Beach Transit, Omnitrans, Riverside Transit Agency, Santa Monica, and a number of 

other operators.

Southern California has led the nation in the provision of accurate and timely traveler 

information, including “real-time” traffic and incident data on our freeway system. 

Information on transit and ridesharing is also available extensively online and through 

electronic media, including “real-time” information on transit. The region recently 

deployed a “5-1-1” traveler information system (similar in concept to 9-1-1) which will 

allow for a one-stop multi-media contact point for all traveler information services. The 

5-1-1 system is part of a national initiative to create a national system of traveler information services.

There have been existing programs among Los Angeles and railroads (SCRRA, UP, and 

BNSF) to implement an interface standard between the rail warning circuit controller 

and traffic signal controller (this interface standard is known as IEEE 1570-2002) for the 

purpose of establishing a “supervised communication circuit.” This standard has been 

promulgated by CPUC, and is now reflected in both the MUTCD and AREMA. 

An extended application of this standard involves the application of Advance Preemption, 

which allows the traffic signal to complete the pedestrian timing for conflicting crosswalks 

Intelligent Transportation Systems 1
2 Intelligent Transportation Systems

prior to the active trains arriving the rail crossing. This extension, however, requires the 

railroad circuitry be designed in such a way, or be modified. This extended application 

is now common for active signalized intersections near rail crossings, for the light-rail 

transits, especially near pedestrian generators. 

The standards for Positive Train Control have been incorporated into the regional architecture and are currently being implemented by Metrolink.

SCAG has a critical role in the development and managemetn of ITS in the region. As the 

Metropolitan Planning Organization, SCAG is charged with developing and maintaining a 

regional ITS architecture. The “architecture” is the regional planning tool for ensuring a 

cooperative process to prioritize and deploy ITS technologies and for identifying critical data connections between institutional stakeholders. The “architecture” assists the 

region in deploying ITS systems that are truly integrated and able to share information 

among many agencies in consistent and compatible formats to achieve improved safety 

and efficiency of transportation operations. SCAG works closely with the county transportation commissions (CTCs), local governments, and Caltrans Districts to update and 

maintain the regional architecture, and assure the use of required systems, engineering 

requirements, and applicable standards, which is required when federal funds are used 

on ITS projects.

Existing System Performance and 

Operational Impacts from ITS

ITS technologies are not a mode of travel; they are a means of assuring that our modes of 

travel are being managed and operated at maximum effectiveness. An example is ramp 

metering of freeways, which is designed to assess the optimal flow rate (highest achievable capacity) and to meter the traffic so that it merges with the flowing traffic in a way 

that minimizes flow disruption that would otherwise reduce the capacity that the lane is 

able to carry. Today, sub-optimal flow on our freeways and arterials, so-called “stopand-go traffic,” creates significant losses to design capacity. ITS technologies allow 

us to observe, confirm, and proactively address these losses in operational efficiency. 

This will allow for rapid response to clear incidents and accidents, adjust ramp metering 

rates, identify bottlenecks and slow approaching traffic to reduce collisions that would 

further diminish the system’s optimal flow rate capacity. Similarly, traffic signal systems 

are monitored for the proper timing of signal phases, traffic volumes, and changes on 

arterials, and optimal timing plans are introduced to maximize arterial flow, and minimize 

unnecessary delay.

The SCAG region has the most extensive system of freeway monitoring detection in the 

United States, with approximately 65 percent of the urbanized freeway system under 

some form of detection. The arterial system has also grown to cover significant portions 

of Los Angeles and Orange County cities, and is increasingly being deployed and interconnected in Riverside and San Bernardino Counties. Ramp metering is also extensively 

deployed throughout the urbanized areas. But, significant gaps in coverage and capability 

of freeway and arterial ITS systems still exist, including limited coverage of ports routes 

and major corridors in and out of the urbanized area.
Intelligent Transportation Systems 3

Future Baseline System Improvements

ITS plays a critical role in the operation and management strategies designed to increase 

the efficiency of the existing transportation system. The 2012 RTP/SCS allocates $7.6 

billion in Transportation System Management measures, which includes ITS. 

The region will continue to update the capabilities of our Caltrans TMC’s, expand ramp 

metering and corridor management strategies, fill detection gaps, increase the use of 

signal system controls, and increase and improve the technical capabilities for transit bus 

and rail systems. ITS systems are not modeled directly in the regional demand model, but 

comparative studies of the impacts shows significant travel time savings on arterials, as 

well as the potential for improving the effective flow rates of our freeways and the ontime performance of our bus and rail system to 95 percent or higher.

ITS will be an increasing part of the regional goods movement strategies. The Ports of 

Los Angeles and Long Beach have identified ITS technologies, specifically automated 

vehicle location (AVL), as a major component in their proposed air quality mitigation 

strategies. Advanced monitoring will assist in achieving system efficiencies in ports and 

intermodal operations, reducing delays and waiting times at gates and destinations, and 

allowing for more flexible dispatching, all of which reduce emissions. Weigh in motion 

systems and enhanced detection will allow for better enforcement of commercial vehicles 

rules, reducing pavement damage, and identifying critical paths for goods movement 

planning in the future.

ITS systems will allow for enhanced capabilities to protect the transportation system and 

respond to emergencies. One goal of the RTP is to integrate transportation system information into a shared use capacity with emergency service responders. Visual safety systems, detection, automated vehicle location, and the ability to share this information with 

public safety agencies will assist in deterring, preparing for, responding to, and recovering from manmade security events and natural disasters. These technologies, although in 

place to manage the transportation system, can assist in providing a deterrence to crime 

and terrorism, as well as assist in major incident responses such as road closure or other 

events requiring the close coordination of evacuation vehicles.

Recommended Policies and Actions

 Maintain and update the Regional ITS Architecture to assure eligibility of federal 

funding from state of the art ITS technologies for regional stakeholders.

 Continue the development of a Regional Configuration Management process among CTCs, 

Caltrans Districts, Ports, and local governments to assure consistent and compatible integration of ITS technologies and interoperable operations.

 Identify funding sources for transportation system operations and management 

strategies, including ITS, to ensure optimal operation of the existing and future 

transportation system in the region. This will be coordinated with the CTCs, 

Caltrans, and other agencies implementing ITS technology.

 Implement near-term ITS priorities to improve the safety and efficiency of the current transportation system, including: ramp metering, increased freeway detection, monitoring of goods movement operations, advanced traveler information 

systems/5-1-1/goods movement information systems, transit vehicle location and 

real-time schedule adherence, Rapid Bus systems, computer-based signal timing 

systems, interconnection between roadway traffic signals and railroad signal systems, automated fare collection and toll collection technologies.

 Identify ITS base systems for future integrated freeway and corridor management 

strategies, including potential congestion pricing systems and High Occupancy 

Toll Lanes.

 Mainstream ITS investments and make ITS systems part of the capital investment in 

new projects to assure optimal operations of new transportation investments.
REGIONAL OFFICES

Imperial County

1405 North Imperial Avenue

Suite 1 

El Centro, CA 92243 

Phone: (760) 353-7800 

Fax: (760) 353-1877

Orange County

OCTA Building 

600 South Main Street

Suite 906 

Orange, CA 92863 

Phone: (714) 542-3687 

Fax: (714) 560-5089 

Riverside County

3403 10th Street

Suite 805 

Riverside, CA 92501 

Phone: (951) 784-1513 

Fax: (951) 784-3925

San Bernardino County

Santa Fe Depot 

1170 West 3rd Street

Suite 140 

San Bernardino, CA 92410 

Phone: (909) 806-3556 

Fax: (909) 806-3572

Ventura County

950 County Square Drive

Suite 101 

Ventura, CA 93003 

Phone: (805) 642-2800 

Fax: (805) 642-2260 

818 West 7th Street, 12th Floor 

Los Angeles, CA 90017 

Phone: (213) 236-1800 

Fax: (213) 236-1825

www.scag.ca.gov

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