The Signalized Left Turn Assist System is an infrastructure based system that will provide information to drivers performing unprotected left turns to judge the gaps in oncoming traffic as well as inform them when other users, such as pedestrians or bicyclists, pose hazards to completing a safe left turn. As illustrated above, the Signalized Left Turn Assist System will combine roadside sensors, infrastructure-based messaging signs, communications and positioning technologies, dynamic maps, and traffic signal interfaces.
Intersection collision avoidance systems use both vehicle-based and infrastructure-based technologies to help drivers approaching an intersection understand the state of activities within that intersection. Cooperative intersection collision avoidance systems (CICAS) have the potential to warn drivers about likely violations of traffic control devices and to help them maneuver through cross traffic. Eventually, CICAS may also inform other drivers (i.e., potential victims) about impending violations as well as identify pedestrians and cyclists within an intersection.
CICAS consists of:
- Vehicle-based technologies and systems-sensors, processors, and driver interfaces within each vehicle
- Infrastructure-based technologies and systems-roadside sensors and processors to detect vehicles and identify hazards and signal systems, messaging signs, and/or other interfaces to communicate various warnings to drivers
- Communications systems-dedicated short-range communications (DSRC) to communicate warnings and data between the infrastructure and equipped vehicles
Understanding Safety Benefits and User Acceptance
The CICAS initiative built on research and operational tests previously conducted under the US DOT's Intelligent Vehicle Initiative. Research activities were closely coordinated with the Vehicle Infrastructure Integration and the Intelligent Vehicle-Based Safety Systems initiatives. The CICAS initiative working group was formed from partnerships with automotive manufacturers, State and local departments of transportation and university research centers throughout America.
Through additional research, system integration activities, and demonstrations, the CICAS initiative produced a system prototype that addressed both control violations and gap acceptance crash problems. The initiative culminated in a series of coordinated field operational tests that led to a solid understanding of safety benefits and user acceptance.
The goals of the CICAS Program were to develop and demonstrate cooperative intersection collision avoidance systems for both violations and gaps; to assess the value and acceptance of cooperative collision avoidance systems; and to develop and provide tools to support industry deployments.
The CICAS initiative supported research, systems integration activities, and demonstrations that produced a system prototype (or set of prototypes) that led to a large-scale field operational test in 2009. To produce this result the initiative:
- developed prototypes of countermeasures against control violations
- continued research activities on countermeasures relating to gap acceptance, and produce prototypes
- completed a prototype that included cooperative vehicle-based and infrastructure components and that addressed both control violations and gap acceptance.
CICAS built on research and operational tests originally conducted under USDOT's Intelligent Vehicle Initiative. The Vehicle Infrastructure Integration (VII) initiative provided the enabling communication capability necessary for cooperative crash avoidance systems by developing and enabling the deployment of on-board units (OBUs) and roadside units (RSUs) for communication and information processing. The VII initiative and the CICAS initiative were closely coordinated, particularly for field operational tests. The CICAS Program also coordinated with the Integrated Vehicle-Based Safety Systems (IVBSS) initiative, especially with regard to the integration of on-board sensors and driver-vehicle interfaces (DVI - a method for how the system communicates to the driver).
The stakeholders involved in this initiative included:
- State Departments of Transportation
- Automotive manufacturers
- U.S. DOT (various modal administrations)
- University transportation research groups
The USDOT, the State Departments of Transportation, and the automotive manufacturers played a key role in providing the background research necessary for developing a prototype of a CICAS. The federal government acted as a facilitator in engaging these and other stakeholders in the conceptualization and development of the CICAS prototype. The federal government was also responsible for defining performance requirements, managing the systems development process, evaluating system effectiveness, and encouraging the market availability of CICAS once they were developed and tested. Ultimately, State and local governments will be responsible for deploying the infrastructure side of the CICAS solution, while automotive manufacturers develop and deploy CICAS solutions in vehicle product lines. Because successful deployment of CICAS required consumer acceptance, it was also of critical importance to engage stakeholders who represented public interests on privacy and liability issues. A formal outreach plan was developed that identified specific stakeholder groups and opportunities for engagement throughout the program.
Program Development Workshops
In 2004 and early 2005, the CICAS Program hosted a series of workshops to gather input for defining the CICAS Program's work plan. The workshops aimed to capture research to date in order to define the concept of "cooperative systems" and to develop a plan for execution of the program. The first workshop was hosted on December 9-10, 2004 and produced a working framework for a potential prototype system.
Proceedings from December 2004 Workshop
- Executive Summary – [HTML, DOC 48KB]
- Workshop Report – [HTML, DOC 149KB]
- Appendix A1 – [HTML, DOC 75KB]
- Appendix A2 – [HTML, DOC 73KB]
- Appendix B1 – [HTML, DOC 98KB]
- Appendix B2 – [HTML, DOC 141KB]
Crash Avoidance Metrics Partnership (CAMP)
The IVI Program established a mechanism to work with the automotive industry on research common to both industry and the government for vehicle-based safety systems. This mechanism is known as CAMP and is a working group comprised of seven automotive companies - BMW, Daimler-Chrysler, Ford, General Motors, Nissan, Toyota, and Volkswagen. CAMP provided the CICAS Program with its relevant intersection research to-date. Through CAMP, the automotive industry played a role as a working partner leading the development of the vehicle-based side of CICAS. CAMP's preparatory analysis laid the groundwork for a vehicle-based framework, which when merged with the infrastructure framework, forms a cooperative system.
The CICAS Program required the use of Dedicated Short Range Communications (DSRC) to provide a means for data to flow between vehicles and the infrastructure regarding the state of activity within the intersection. The DSRC standards were completed in 2004 and have been available for use. Prototype DSRC roadside units (RSUs) were integrated into CICAS as one means of establishing the communications link between intersection infrastructure and vehicles.
Violation Warning System - The CICAS-V System is a vehicle-based driver warning system that alerts drivers to potential violations of stop signs or red traffic lights. As illustrated above, the CICAS-V system will 1) Collect and process data from enhanced map databases, positioning technologies, and wireless communications devices that provide traffic signal phase and timing plans; and 2) Synthesize this data with split-second timing to determine the likelihood of a violation.
A number of states were involved in addressing the intersection collision problem through both research as well as demonstration. California focused on systems integration and the left turn across path problem, particularly in urban areas. Michigan hosted a prototype of an early cooperative system to test DSRC and the capability of broadcasting signal information to equipped vehicles. Minnesota focused on lateral direction crashes when minor roads intersect major arterials, particularly in rural areas. Minnesota also demonstrated an infrastructure-based rural intersection collision avoidance system and led an eight-state, pooled-funds demonstration to note the differences in application across varying geographies and driving characteristics. Virginia focused on near-term deployable approach warnings for traffic signals and signs, also took the lead in defining the infrastructure-based framework, and led the States in working with CAMP to integrate the two frameworks into one cooperative system.
Much of the State research and demonstration was conducted in cooperation with leading research universities under the Infrastructure Consortium - a research program established under the Intelligent Vehicle Initiative (IVI) for conducting intersection decision support system research focusing on both infrastructure-based and collaborative intersection collision avoidance systems. Three research universities formed the Infrastructure Consortium - the University of California at Berkeley Partners for Advanced Transit and Highways, the University of Minnesota Intelligent Transportation Systems Institute, and the Virginia Polytechnic Institute/Virginia Tech Transportation Institute.
Human Factors Research
A critical aspect of CICAS was the way in which information is presented to the driver (or a potential victim of a crash), whether in the vehicle or on the infrastructure. Human factors research has been looking at how drivers most effectively receive and act upon information and how information can be delivered with the least amount of unintended consequences. Both FHWA and the National Highway Traffic Safety Administration (NHTSA) have been conducting research in conjunction with universities and other research entities to understand the best form of interfacing with drivers to deliver information and warnings. More human factors research is needed before a decision is made regarding which type of interface will be used in CICAS.
- Major Initiative Status Report - January 2008
- Intelligent Vehicle Initiative (IVI) Infrastructure Consortium
- National Agenda on Intersection Safety
- Rural Intersections
- Automated Pedestrian Detection at Intersections – [PDF, 592KB]
- Facts and Statistics
- Advocates for Highway and Auto Safety – Intersection Safety
- International Scan on Intersection Safety
- Making Intersections Safer
- Intersection Safety Briefing Sheets
- Information on Signalized Intersections
Cooperative Intersection Collision Avoidance System Limited to Stop Sign and Traffic Signal Violations Final Report with Appendix List
- Cooperative Intersection Collision Avoidance System Limited to Stop Sign and Traffic Signal Violations
- Appendix A: Task 3 Final Report Human Factors Development and Testing Cooperative Intersection Collision Avoidance System Limited to Stop Sign and Traffic Signal Violations
- Appendix_A-1_Task 3_1 - Report Cooperative Intersection Collision Avoidance System Limited to Stop Sign and Traffic Signal Violations
- Appendix_A-2_Task 3_2 Report Cooperative Intersection Collision Avoidance System Limited to Stop Sign and Traffic Signal Violations
- Appendix_A-3_Task 3_3 Report Cooperative Intersection Collision Avoidance System Limited to Stop Sign and Traffic Signal Violations
- Appendix_A-4_Task 3_4 Report Cooperative Intersection Collision Avoidance System Limited to Stop Sign and Traffic Signal Violations
- Appendix B: Task 4 - Final Phase 1: Concept of Operations, Appendix_B_CICAS-V_ConOps_Final v0301 02-10-09 Cooperative Intersection Collision Avoidance System Limited to Stop Sign and Traffic Signal Violations
- Appendix C-1: Task 4 - Final Phase 1: High-Level Requirements Specification Appendix_C-1_CICAS-V_HRS_Final_v0401 Cooperative Intersection Collision Avoidance System Limited to Stop Sign and Traffic Signal Violations
- Appendix C-2: Task 5 - Final Phase 1: System Requirements Specification Appendix_C-2_CICAS-V_SRS_v0301 Cooperative Intersection Collision Avoidance System Limited to Stop Sign and Traffic Signal Violations
- Appendix D: Task 5 - Final Phase 1: System Architecture Description
- Appendix E-1: Task 6 - Final Phase 1: Performance Specification Vehicle
- Appendix E-2: Task 6 - Final Phase 1: System Design Specification Infrastructure
- Appendix F: Task 8 Prototype Build and Testing
- Appendix G: Task 10 Integration of Subsystems, Building of Prototype Vehicles, Outfitting Intersections
- Appendix H-1: Task 7 Final System Test Plan and Procedures Cooperative Intersection Collision Avoidance System Limited to Stop Sign and Traffic Signal Violations
- Appendix H-2: Task 11 Final Report Objective Tests Cooperative Intersection Collision Avoidance System Limited to Stop Sign and Traffic Signal Violations
- Appendix I: Task 12 Infrastructure and Vehicle DAS Functional Designs
- Appendix J: Task 13 Final Report: Recommended Basic FOT Design and Selection Procedures
- Commercial Vehicle Information Systems and Networks (CVISN)
- Intermodal Freight Technology
- Federal Highway Administration Freight Office
- Intermodal Freight Technology Working Group
Related Areas of Interest
Intelligent Vehicle Initiative (IVI)
The IVI Program initiated research into how advanced transportation technologies can be applied to address the intersection collision problem. The IVI Program provided the foundational research into infrastructure systems, in-vehicle systems, human factors, and communications technologies that are now being combined into cooperative systems in the CICAS Program.
Connected Vehicle Research
Connected vehicle research is focused on preventing crashes by enabling active safety applications that rely on interoperable wireless communication among vehicles and with infrastructure elements, via an open communications platform. The wireless networking capabilities at the heart of connected vehicle technology also support numerous mobility, environmental, and convenience applications.
Integrated Vehicle Based Safety Systems (IVBSS)
The IVBSS Program is providing an approach to integrating new technology systems on vehicles – systems for run-off-the-road warning, forward collision warning, lane-change warning, and others. To be effective for the driver, these systems need to be integrated into one seamless, single interface to ensure against driver distraction from multiple warnings. Because a deployable CICAS will require similar integration with these types of systems, the IVBSS results will play an important role in the design and evolution of CICAS as it moves to market.
ITS Technologies to Reduce Pedestrian Injuries and Fatalities
The CICAS Program seeks to incorporate new technologies into the prototype system(s) that help the infrastructure or vehicle recognize the presence of pedestrians near and in intersections. The CICAS Program will draw upon the lessons learned from this exploratory initiative when designing and testing the CICAS.
National Highway Traffic Safety Administration
ITS Safety Research Program Manager
FHWA Office of Safety RD&T
CICAS Vehicle Systems Manager
National Highway Traffic Safety Administration,