Exploratory Advanced Research . . . Next Generation Transportation Solutions

near-term sensor technologies, the adoption of a 

standardized communication protocol, and the 

ability to deploy incrementally, allowing expansion 

to other intersections and adaptation to increasing 

numbers of autonomous vehicles. Absolute collision prevention, even under conditions of communications failure, and high levels of efficiency are 

primary goals for the system.

Making a Reservation

For intersection control, the researchers have introduced a radically different system of “reservations,” in which a vehicle approaching the intersection “calls ahead” via digital short-range 

communications to the “intersection manager” to 

request a block of space–time within which to traverse the intersection. The request transmits the 

vehicle’s time of arrival, velocity, size, acceleration 

capability, and arrival and departure lanes. An intersection control policy then simulates the vehicle’s trajectory across the intersection, calculating 

the clear space required for passage and approving or denying the vehicle’s request based on the 

space–time requirements of other processed trajectories. The intersection manager transmits a 

confirmation, rejection, or alternative slot to the 

approaching vehicle. Simulations of this system 

with up to three lanes in each of four directions 

show dramatic reductions in waiting time compared with intersections with traditional controls.

The project proposes innovations in five areas: 

traffic signal timing, intersection collision avoidance, autonomous traffic infrastructure, autonomous driving, and multi-agent systems. Its major 

tasks are the development of a detailed vehicle–

infrastructure communication protocol and the development and testing of prototype agent-control 

algorithms. 

“This project aims to take full advantage of the 

sensing and control capabilities of autonomous 

vehicles to reduce congestion,” says Gene McHale 

of FHWA’s Office of Operations Research and 

Development. “When traffic flow is optimized, auThe Exploratory Advanced Research Program Fact Sheet

The Promise of Autonomous Vehicles

The precision with which autonomous vehicles can 

be controlled is key to the many benefits they offer: 

improved safety, less congestion, lower emissions, 

and reductions in the high costs of wasted time and 

fuel. Vehicles with features of autonomy are already 

emerging on the market, but the corresponding 

traffic control systems that could unleash the full 

potential of autonomous vehicles are yet to be developed. In addition, the transition to full automation is likely to be long and gradual, requiring traffic 

control systems to safely accommodate a mix of autonomous and human-driven vehicles in everchanging proportions. An advanced intersection 

control mechanism will be critical to optimizing traffic flow in complex networks. 

The intersection control system proposed in this 

EAR study promises to process traffic more efficiently than traffic lights and stop signs can without 

compromising safety. Its development is guided by 

a set of criteria that includes the use of current or 

Traffic congestion costs the Nation billions of dollars each year in wasted 

fuel and lost productivity. Traditional traffic 

control systems cannot keep pace with this 

growing problem, but systems that work 

with self-driving vehicles may afford a more 

radical approach. “Intersection Control for 

Autonomous Vehicles,” an Exploratory 

Advanced Research (EAR) Program project, 

is pursuing a new way to keep traffic moving. This project, awarded by the Federal 

Highway Administration (FHWA) in 2008, is 

being conducted at the University of Texas 

at Austin.

Beyond Traffic Signals: A Paradigm Shift 

Intersection Control for Autonomous Vehicles
tonomous vehicles have the potential to substantially increase roadway capacity while eliminating 

crashes caused by human error.”

Future Efforts

The next step is to determine real-world deployment feasibility. Following evaluation of the protocols and algorithms for an individual intersection 

and a full-failure mode analysis, the project will simulate the feasibility of the system in networks of intersections. Actual physical implementation will first 

use small autonomous lab robots and later a fullsize autonomous vehicle. Ultimately, the project will 

deliver a prototype software implementation of the 

intersection manager and a detailed communication protocol.

“The beauty of this system as proposed,” commented David Yang, FHWA’s technical representative on the project, “is its potential to facilitate the 

transition from today’s human-driven vehicles to an 

era when autonomous vehicles are the norm and 

perhaps even to accelerate the change by demonstrating a faster and safer way to get around.” 

Learn More

For more information on this EAR Program project, 

contact David Yang, FHWA Office of Operations 

Research and Development, at 202-493-3284 

(email: david.yang@dot.gov).

What Is the Exploratory 

Advanced Research Program?

FHWA’s Exploratory Advanced Research (EAR) 

Program focuses on long-term, high-risk research with a high payoff potential. The program addresses underlying gaps faced by applied highway research programs, anticipates 

emerging issues with national implications, 

and reflects broad transportation industry 

goals and objectives. 

To learn more about the EAR Program, visit 

the Exploratory Advanced Research Web site 

at www.fhwa.dot.gov/advancedresearch. The 

site features information on research solicitations, updates on ongoing research, links to 

published materials, summaries of past EAR 

Program events, and details on upcoming 

events. For additional information, contact 

David Kuehn at FHWA, 202-493-3414 (email: 

david.kuehn@fhwa.dot.gov), or Terry Halkyard 

at FHWA, 202-493-3467 (email: terry.halkyard@

fhwa.dot.gov). 

Publication No. 

FHWA-HRT-10-023

HRTM-04/11-09(1M)E

Beyond Traffic Signals: A Paradigm Shift 

Intersection Control for Autonomous Vehicles

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