Arterial Management 

Office of Operations

21st Century Operations Using 21st Century Technologies

Arterial Management

Challenges

In many major metropolitan areas, the freeway system is

functioning at or beyond the capacity for which it was

designed. Many drivers are choosing to use arterial streets

instead. The resulting stress on the arterial systems creates

gridlock on the thoroughfares that define our cities and

suburbs. Fortunately, the Federal Highway Administration’s

(FHWA) Office of Operations has identified effective ways to

manage this growing trend.

What We’ve Learned 

Arterial Management strategies are used to effectively and

successfully manage traffic and control arterial roadways.

Examples are:

● Traffic signal improvements 

● Advanced traffic signal control

● Traffic monitoring

● Access management

Traffic signal improvements include updating equipment,

updating timing plans, and interconnecting signals. Over 75

percent of the country’s 330,000 signals could be improved

by updating the equipment or by simply adjusting the timing.

Traffic signal retiming alone can produce benefit cost ratios

as high as 40 to 1. That is, for every $1 invested in optimizing

the timing or traffic signals, $40 is returned to the public in

time and fuel savings.

Advanced traffic

signal control

involves coordinating

groups of signals,

operating signal

control systems that

respond and adapt 

to traffic needs, or

installing a priority

control system.

Installing advanced computerized controls can result in a 20

percent reduction in travel time when compared to noninterconnected pre-timed signals operating with old timing plans.

Traffic monitoring on arterials can include incident detection and follow-up action to remove incidents, intersection

surveillance and monitoring using loop detectors and video

monitoring, and area-wide traffic surveillance. The Automated

Traffic Surveillance and Control Program in Los Angeles,

California uses a computerized signal control system that has

been in operation since 1984. It manages 1,170 intersections

and 4,509 detectors for signal timing optimization. The

program has resulted in a 13 percent decrease in fuel 

consumption, 14 percent decrease in emissions, 41 percent

reduction in vehicle stops, 18 percent reduction in travel time,

16 percent increase in average speed, and a 44 percent

decrease in delay.

Access management is a set of techniques that State and

local governments can use to control access to highways,

major arterials, and other roadways. The benefits of access

management include improved movement of traffic, reduced

crashes, and fewer vehicle conflicts. Four proven access

management techniques are:
Access Spacing: Increasing the distance between traffic

signals improves the flow of traffic on major arterials,

reduces congestion, and improves air quality for heavily

traveled corridors.

Driveway Spacing: Fewer driveways spaced further

apart allow for more orderly merging of traffic and

present fewer challenges to drivers.

Turning Lanes: Dedicated left- and right-turn lanes,

indirect left-turns and U-turns, and roundabouts keep

through-traffic flowing. Roundabouts represent a potential solution for intersections with many conflict points.

Median Treatments: Two-way left-turn lanes (TWLTL)

and nontraversible, raised medians are examples of some

of the most effective means to regulate access and reduce

accidents.

The safety benefits of median improvements are shown

below. Studies indicate a decrease in crashes of 40 to 70

percent when these treatments are implemented.

Future Direction

The Office of Operations Arterial Management program

covers three major focus areas: arterial management, traffic

signal timing, and access management. The program

addresses research and development and deployment

support initiatives.

Research and development projects enhance tools such as

algorithms for traffic signal software, traffic detection

devices, or tools to aid in the collection of data. ACS Lite is a

current initiative involving the modification of existing adaptive control software to allow it to operate on legacy traffic

signal systems.

Deployment support programs distribute and demonstrate

current technology ready to be used by our transportation

partners. Activities include developing training, technical

documents, handbooks and manuals for transportation practitioners, and the continued revitalization and delivery of

formal National Highway Institute training courses such as

those covering Computerized Traffic Signal Systems and

Traffic Control Signalization and Software. These courses are

being formatted for Web-based delivery so practitioners

around the country can learn on their own schedules.

Future plans include continued expansion of the Traffic

Signal Timing focus area to increase emphasis on communicating the importance of high quality, current traffic signal

timing plans. A recent study of the signal timing process

identified the steps necessary to reach optimally timed

signals and where opportunities exist for automation and

addressing issues such as staff shortages and budgetary 

constraints. These initiatives—achieved through research,

education, outreach and guidance, and tool development—

support the Office of Operation’s goal of ”21st Century

Operations using 21st Century Technologies.”

April 2004

FHWA-OP-04-036

For more information on FHWA Office of Operations activities, visit our web site at

www.fhwa.dot.gov/operations

9

8

7

6

5

4

3

2

1

0

Crashes Per Million VMT

Undivided TWLTL Nontraversible

Median Type

Urban

Rural