United States Government Accountability Office

GAO Report to Congressional Requesters

SURFACE 

TRANSPORTATION 

Efforts to Address 

Highway Congestion 

through Real-Time 

Traffic Information 

Systems Are 

Expanding but Face 

Implementation 

Challenges 

November 2009 

GAO-10-121R 
What GAO Found

United States Government Accountability Office

Why GAO Did This Study

Highlights

Accountability Integrity Reliability

November 2009

SURFACE TRANSPORTATION 

Efforts to Address Highway Congestion through RealTime Traffic Information Systems Are Expanding 

Highlights of GAO-10-121R, a report to but Face Implementation Challenges

congressional requesters 

Growing congestion on our nation’s 

roads results in wasted time and 

fuel, which adversely affects the 

economy and the environment. 

State and local government 

agencies and private companies 

disseminate real-time traffic 

information to help travelers 

decide whether to use alternative, 

less congested routes. Legislation 

enacted in 2005 required the U.S. 

Department of Transportation 

(DOT) to establish the Real-Time 

System Management Information 

Program, in order to provide states 

the capability to monitor traffic and 

travel conditions on major 

highways and share that 

information. As requested, this 

GAO report addresses, among 

other things, (1) how the public 

and private sectors disseminate 

real-time traffic information to the 

public, (2) actions DOT has taken 

to establish the Real-Time System 

Management Information Program, 

and (3) experts’ views on the need 

for a nationwide real-time traffic 

information system and its 

potential characteristics. 

To conduct this study, GAO visited 

sites in California and Florida, 

which have well-developed traffic 

information systems; reviewed and 

analyzed DOT reports and data; 

and interviewed transportation 

officials, experts, and other 

stakeholders. GAO is not making 

any recommendations at this time 

because DOT has not finalized the 

proposed rule it issued in January 

2009, and there was no consensus 

from the experts GAO interviewed 

as to whether an increased federal 

role in this area is appropriate or 

what this role might be. 

States and local agencies and the private sector use a variety of services and 

technologies to disseminate real-time traffic information to the public. For 

example, state and local agencies deploy electronic traffic signs and services 

that provide information via a nationwide 511 phone number, and private 

companies operate Web sites that provide information for cities across the 

country. The coverage provided by these services and technologies is 

expanding, but there are gaps in coverage and variations in aspects of realtime traffic information, such as the quality of the data collected and the 

extent to which state and local agencies share their data. The private sector is 

expanding coverage, in part by using newer technologies to increase the 

collection of traffic data. Like the public sector, the private sector faces 

limitations to its coverage and data quality. 

To establish the Real-Time System Management Information Program, DOT’s 

Federal Highway Administration (FHWA) issued a proposed rule in January 

2009 that, when finalized, could improve the coverage, quality, and sharing of 

traffic information. The rule proposes requirements for states to make 

available certain traffic information, such as travel time, on major highways 

and to meet data quality standards, including standards for timeliness. State 

and local government officials GAO interviewed said that these improvements 

would allow the public to better select the most efficient route to reach their 

final destination, which could reduce congestion and yield other benefits. Yet 

state and local officials also told GAO that the proposed rule’s time frames to 

develop the program are too short and would be difficult to implement 

without additional funds. DOT expects to issue the final rule in February 2010 

and is currently considering options to address such concerns. According to 

FHWA, its division offices will monitor states’ compliance with the final rule. 

Experts GAO interviewed generally agreed that a nationwide real-time traffic 

information system is needed to help address current gaps in information 

coverage and inconsistencies in data quality. Many of these experts noted 

that reported mobility and environmental benefits, such as travel time savings 

and reduced emissions, could be increased under a nationwide system. 

However, experts held varying views on the potential characteristics of such a 

system. Some said that the anticipated results of current efforts related to 

real-time traffic information by DOT, states, and the private sector would lead 

to the development of a nationwide real-time traffic information system and 

considered these efforts sufficient. Others envisioned a nationwide system 

that would go beyond current efforts. For example, in their visions, DOT 

would take a strong leadership role or partner more with the private sector to 

disseminate information. However, experts cited potential challenges in 

designing and implementing a nationwide system, including reaching 

consensus on the form of the nationwide system and funding constraints. 

DOT reviewed a draft of this report and provided a technical comment that 

GAO incorporated. 

View GAO-10-121R or key components.

For more information, contact David J. Wise 

at (202) 512-2834 or wised@gao.gov. 
United States Government Accountability Office

Washington, DC 20548 

November 30, 2009 

Congressional Requesters 

Growing congestion on our nation’s roads is a challenge for many metropolitan and 

nonmetropolitan areas. Traffic congestion results in wasted time and fuel for travelers and 

commercial truckers, thereby adversely affecting the economy and the environment. 

According to transportation researchers, in 2007, congestion in urban areas resulted in 4.2 

billion hours of time spent waiting in traffic and 2.8 billion gallons of extra fuel used, at a 

total cost of $87.2 billion.1

 Among the tools that the U.S. Department of Transportation 

(DOT) has identified to help reduce congestion are real-time traffic information systems and 

technologies,2

 which can be used to disseminate traffic information to the public to help 

travelers—including commuters and long-distance travelers—decide whether to use 

alternative, less congested routes. 

Agencies in state governments and metropolitan areas, as well as private companies, deploy 

and operate real-time traffic information systems and technologies to provide traffic and 

travel information to the public. Recognizing the potential for real-time traffic information to 

decrease congestion, Congress incorporated requirements related to real-time traffic 

information into the 2005 authorization of federal surface transportation programs. 

Specifically, the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy 

for Users (SAFETEA-LU) made DOT responsible for establishing a program—called the RealTime System Management Information Program—that would provide all states the capability 

to monitor real-time traffic and travel conditions on major highways and enable them to 

share that information with state and local governments and the traveling public.3

 

Furthermore, DOT has identified real-time traffic information initiatives as high-priority 

efforts to address congestion. 

Given the potential benefits of real-time traffic information to the nation, the House 

Committee on Transportation and Infrastructure asked us to provide information on existing 

real-time traffic information systems, current and potential future efforts to improve such 

 

1

David Schrank and Tim Lomax, 2009 Urban Mobility Report (College Station, Texas: Texas 

Transportation Institute, 2009). 

2

“Real-time” is a relative measure. Information delivery times generally range between 10 and 20 

minutes. 

3

In 2005, SAFETEA-LU authorized funding for federal surface transportation programs for highways, 

highway safety, and transit. See Pub. L. No. 109-59, 119 Stat. 1144. Section 1201 of SAFETEA-LU 

established the Real-Time System Management Information Program but did not provide separate 

funding to implement this program. Section 1201 of SAFETEA-LU authorizes states to use their 

federal-aid highway funding for efforts related to this program. 

GAO-10-121R Real-Time Traffic Information Systems 
systems and create a nationwide system, as well as the impacts and costs of existing systems. 

Our objectives for this review were to determine (1) how state and local agencies and the 

private sector disseminate real-time traffic information to the public, and the completeness of 

current coverage; (2) what actions DOT has taken to establish the Real-Time System 

Management Information Program required by SAFETEA-LU, and stakeholders’ views on 

these actions; and (3) how selected experts view the need for and benefits of a nationwide 

real-time traffic information system, how they envision such a system, and what the related 

challenges may be. The results of our work are contained in enclosure I. To address the 

committee’s interest in the impacts and costs of existing systems, we examined what studies 

have found about the impacts—particularly on mobility, the environment, and the 

economy—and the costs of these systems. These issues are discussed in enclosure II. This 

report focuses on real-time traffic information that is disseminated to the public.4

 

To address the first objective, we interviewed—and reviewed relevant reports and studies 

obtained from—DOT officials; representatives of national organizations involved in real-time 

traffic information initiatives, such as the Intelligent Transportation Society of America; state 

and local transportation officials; and private companies involved in real-time traffic 

information initiatives.5

 We also conducted site visits in California and Florida6 and analyzed 

2007 data from DOT surveys on the deployment of Intelligent Transportation System (ITS) 

technologies, including real-time traffic information technologies, to determine the types of 

real-time traffic information technologies used in metropolitan areas and the coverage 

provided by these technologies.7

 To address the second objective, we reviewed relevant 

sections of SAFETEA-LU, interviewed DOT officials on actions the department has taken to 

address SAFETEA-LU’s requirement that DOT establish the Real-Time System Management 

Information Program, and reviewed DOT’s proposed rule and guidance related to this 

program. To determine stakeholders’ views on DOT’s proposed program, we interviewed 

selected state and local officials and two private companies that provide real-time traffic 

data, and also analyzed comments that stakeholders submitted to DOT on the proposed 

 

4

Real-time traffic information can also be used for a range of traffic management purposes. For 

example, traffic managers can use this information to control traffic through signal timing, detect 

traffic incidents, and monitor congestion trends. However, traffic management is not in the scope of 

this review. 

5

We selected the four private companies to interview because they were identified by DOT, the 

American Association of State Highway and Transportation Officials, and the Intelligent 

Transportation Society of America as key companies involved in real-time traffic information 

collection, aggregation, and dissemination. 

6

We interviewed state and local officials in California and Florida because, among other reasons, they 

have well-developed real-time traffic information systems and have deployed a range of technologies 

to collect and disseminate real-time traffic information. 

7

ITS consists of a range of communications, electronics, and computer technologies—including those 

that collect, aggregate and translate, and disseminate real-time traffic information—that are designed 

to improve traffic flow and safety. DOT’s ITS deployment surveys sought responses from state and 

local agencies to questions on the deployment of various ITS technologies, including real-time traffic 

information technologies, in 108 large metropolitan areas. The metropolitan areas selected are those 

that have populations of more than 50,000. The most recent surveys were conducted in 2007. We 

reviewed the reliability of the survey data and determined that the data were sufficiently reliable for 

the purposes of this report. See enclosure III for more details on our methodology. 

2 GAO-10-121R Real-Time Traffic Information Systems 
program.8

 To address the third objective, we interviewed 19 experts from DOT, state and 

local transportation agencies, academia, and the private sector. (See enclosure III, table 6.) 

We identified these experts with assistance from the National Academy of Sciences, seeking 

geographic diversity and expert knowledge of various aspects of real-time traffic information 

systems and technologies. Finally, to obtain information on the impacts and costs of realtime traffic information systems, we identified and reviewed relevant studies from selected 

literature databases. The studies we reviewed quantified the impacts of real-time traffic 

information technologies and systems, discussed the costs, or reported the results of benefitcost analyses. We reviewed the methodologies of these studies to ensure that they were 

sound and determined that they were sufficiently reliable for our purposes. 

We conducted this performance audit from January 2009 to November 2009, in accordance 

with generally accepted government auditing standards. Those standards require that we 

plan and perform the audit to obtain sufficient, appropriate evidence to provide a reasonable 

basis for our findings and conclusions based on our audit objectives. We believe that the 

evidence obtained provides a reasonable basis for our findings and conclusions based on our 

audit objectives. Additional information about our scope and methodology is provided in 

enclosure III. 

Background 

Real-time traffic information systems, along with other types of ITS, can be used to improve 

traffic flow and reduce congestion.9

 Traffic congestion results from many sources, such as 

recurring high levels of daily traffic, as well as nonrecurring events like traffic incidents, 

special events, and bad weather that can limit the usable physical capacity of existing 

roadways. Existing research has shown that real-time traffic information systems can 

alleviate traffic congestion by providing travelers with information on traffic and other travel 

conditions, as well as on alternative routes. See enclosure II for information regarding this 

research. Real-time traffic information is one type of traveler information disseminated to 

the public. Other types of traveler information include transit, weather, and parking 

information. 

State and local agencies, as well as private companies, deploy real-time traffic information 

systems that collect real-time traffic data using various technologies, aggregate and translate 

these data into useful information, and disseminate that information to the public using 

various technologies (see fig. 1).10,11 The technologies that support real-time traffic 

 

8

The state and local officials we interviewed included those we met with during our site visits and 

those the National Academy of Sciences identified as experts in the areas covered by our third 

objective. The private companies we interviewed were those identified as key data providers by the 

academy, as well as through our own work. 

9

ITS technologies can also be used for improving safety and for transit management. In 2005, we 

issued a report on the extent to which ITS is used as a tool to reduce congestion. See GAO, Highway 

Congestion: Intelligent Transportation Systems’ Promise for Managing Congestion Falls Short, and 

DOT Could Better Facilitate Their Strategic Use, GAO-05-943 (Washington, D.C.: Sept. 14, 2005). 

10Some local agencies have agreements with their respective state departments of transportation to 

collect, aggregate, and disseminate real-time traffic information to the public. Some state and local 

agencies also contract with private companies to conduct such activities. 

11Public agencies also use real-time traffic information for traffic management. 

3 GAO-10-121R Real-Time Traffic Information Systems 
information collection and dissemination are rapidly evolving. Travelers, for example, are 

increasingly using newer technologies—such as cell phones that can access Web sites and 

receive text messages and in-vehicle navigation devices—to obtain traffic information during 

travel.12

Figure 1: Examples of Technologies Associated with Real-Time Traffic Information Systems 

Data

collection

Data aggregation

and translation

Information

dissemination

Source: GAO.

Real-time traffic data

are collected using

various technologies.

Private and public entities

aggregate and translate

these data into information.

Information is disseminated

to the public through

various technologies.

Fixed sensorsa

Video surveillance

cameras

Aerial surveillance

helicopters

Vehicle probesb

Telephone

Dynamic

message signsd

Radio/highway

advisory radioc

Television

Internet

TRAFFIC

INFO TUNE RADIO

TO 530 AM

Devices used in 

vehicles (e.g., cell 

phones, navigation 

devices)

a

A fixed sensor is a technology that is stationary at the roadside or embedded in the road to monitor traffic flow. 

b

Vehicle probes use roaming vehicles and portable devices to collect data on travel times. Vehicle probes include cell phones 

and Global Positioning System (GPS) devices. 

c

Highway advisory radio uses radio stations to broadcast traffic- and travel-related information to travelers using AM radio. 

d

Dynamic message signs are permanent or portable electronic traffic signs that give travelers information on traffic conditions 

and travel times, among other things. 

Real-time traffic information systems disseminate various types of information to the public 

such as 

• road closure information, including road or lane closures that result from 

construction, maintenance, special events (such as parades), crashes or other 

incidents; 

• weather conditions affecting roadways and road conditions; and 

• traffic flow information, such as travel times, travel delays, or vehicle speeds. 

Travelers can use real-time traffic information to help make decisions before they travel 

 

12The potential for drivers using cell phones and in-vehicle technologies to become distracted has 

become a major safety concern. Some states have banned or restricted the use of cell phones while 

driving. In 2008, GAO addressed safety concerns associated with cell phones and in-vehicle 

technologies in its report, Highway Safety: Foresight Issues Challenge DOT’s Efforts to Assess and 

Respond to New Technology-Based Trends, GAO-09-56 (Washington, D.C.: Oct. 3, 2008). However, the 

impacts of these technologies on safety are not within the scope of this review.

4 GAO-10-121R Real-Time Traffic Information Systems 
(pretrip) and during travel (en route). The need for various types of information depends on 

the traveler. For example, to reach their destination as efficiently as possible, some 

commuters may need pretrip information, such as travel delays or times, so that they can 

adjust their route or time of departure. Commercial drivers may be more concerned with 

obtaining en route information, such as construction or roadway conditions, since their long 

itinerary does not allow them to observe real-time traffic conditions for their entire trip prior 

to their departure. Interregional travelers may need traffic information for both their origin 

and destination, sometimes requiring them to retrieve information from several real-time 

traffic information systems operated by various agencies. 

DOT promotes the deployment of real-time traffic information technologies. For example, 

DOT’s ITS Joint Program Office and the Federal Highway Administration (FHWA) promote 

the deployment of these technologies through activities such as conducting research, 

providing technical assistance to state and local agencies, and acting as a clearinghouse for 

guidance, best practices, and lessons learned. In addition, DOT’s Research and Innovative 

Technology Administration (RITA) ITS Web site includes both deployment statistics and 

databases on the benefits and costs of various ITS technologies, including real-time traffic 

technologies. Furthermore, DOT, through cooperative agreements with standards 

development organizations such as the Institute of Transportation Engineers, helps to 

develop ITS standards that define, among other things, how ITS systems (including real-time 

traffic information systems), products, and components can exchange information. In 2005, 

SAFETEA-LU gave DOT the responsibility of establishing the Real-Time System Management 

Information Program. SAFETEA-LU also required DOT to establish data exchange formats to 

facilitate the sharing of traffic data across jurisdictional boundaries and the availability of 

traffic information nationwide. DOT is currently developing an ITS strategic plan that will 

identify the direction, goals, and objectives for the department’s ITS program over the next 5 

years. In developing this strategic plan, DOT is working to further define its role in 

promoting real-time traffic information systems. 

Agency Comments 

We provided a draft of this report to DOT for its review and comment. DOT officials 

provided a technical comment on our report, which we incorporated. 

______________________________________ 

We are sending copies of this report to interested congressional committees and the 

Secretary of Transportation. The report also is available at no charge on the GAO Web site at 

http://www.gao.gov. 

If you or your staff have any questions on this report, please contact me at (202) 512-2834 or 

wised@gao.gov. Contact points for our Offices of Congressional Relations and Public Affairs 

may be found on the last page of this report. GAO staff who made contributions to this 

report are listed in enclosure IV. 

David J. Wise 

Director, Physical Infrastructure Issues 

Enclosures 

5 GAO-10-121R Real-Time Traffic Information Systems 
6 GAO-10-121R Real-Time Traffic Information Systems 

List of Requesters 

The Honorable James L. Oberstar 

Chairman 

The Honorable John L. Mica 

Ranking Member 

Committee on Transportation and Infrastructure 

House of Representatives 

The Honorable Peter A. DeFazio 

Chairman 

The Honorable John J. Duncan, Jr. 

Ranking Member 

Subcommittee on Highways and Transit 

Committee on Transportation and Infrastructure 

House of Representatives 

The Honorable Mike Rogers 

House of Representatives 

The Honorable Russ Carnahan 

House of Representatives 
Enclosure I 

Dissemination 

and Coverage 

Federal Role 

• The Department of 

Transportation (DOT) initiated 

the development of 511 

Traveler Information Services 

by asking the Federal 

Communications Commission 

(FCC) to set aside a three-digit 

telephone number nationwide 

for traveler information 

services. FCC granted this 

request in July 2000 and issued 

a rule on 511 stating that DOT’s 

role was to “facilitate 

ubiquitous deployment” of 

these services. The rule went 

into effect in February 2001. 

• In response, DOT helped form 

the 511 Deployment Coalition—

a coalition of public agencies, 

industry groups and 

associations, and private 

companies—to encourage the 

growth of 511 services. 

• DOT provided technical 

expertise and limited start-up 

funds. DOT offered money to 

all states, up to $100,000, for 

planning the implementation of 

511 services. 

• DOT’s current role is to 

• provide “targeted 

assistance” with the goal 

of having 511 deployed 

nationwide, and 

• create awareness of the 511 

system. 

Public and Private Sectors Use a Variety of 

Dissemination Technologies but Gaps in 

Coverage Exist 

State and Local Agencies Disseminate Traffic Information 

through 511 Traveler Information Services 

• Most states and some local agencies disseminate traffic information, 

as well as other types of traveler information, through 511 Traveler 

Information Services (see fig. 2). 

• These services provide information via the telephone (using an 

interactive voice response automated system) and the Internet. 

By dialing the three-digit number or accessing the state or local 

511 Web site, travelers can obtain various types of traveler 

information, including information on traffic and road conditions 

as well as construction- and weather-related traffic problems. 

• The types of information provided by these services vary. For 

example, some services provide information on travel times and 

roadway weather conditions, while others do not. In addition, the 

way that information is presented on 511 Web sites varies. 

• According to the 511 Deployment Coalition, as of September 2009, 39 

services were operating in 36 states. In addition, 511 services were 

available to over 181 million Americans (60 percent of the population), 

according to DOT. 

• Thirty-two were statewide services. 

• Seven were metropolitan or regional services. California has four 

511 services operating within its borders. 

• Some metropolitan or regional 511 services, such as those in 

California, are operated by local agencies; while others, such 

as those in Missouri and Massachusetts, are operated by the 

respective state department of transportation. 

• While the volume of calls received by 511 services varies significantly, 

overall, these services have received a large number of calls. 

According to the 511 Deployment Coalition, as of July 2009, these 

services have received over 151 million calls nationwide since their 

inception in 2001.1

 

1

Similar nationwide usage information is not available for 511 Web sites because 

this usage is not tracked consistently by DOT, states, or metropolitan areas. 

1 GAO-10-121R Real-Time Traffic Information Systems 
Dissemination 

and Coverage 

State and Local Agencies’ 511 Services (continued) 

Source: San Francisco Bay Area’s Metropolitan Transportation

Commission.

• 511 services are expanding. For example, Pennsylvania launched its 

service in September 2009, and a five-county system in Southern 

California is expecting to launch its service by the end of 2009. Four 

additional states—Delaware, Maryland, Mississippi, and South 

Carolina—are planning to have operational 511 services in 2010. 

• Although 511 services are expanding, some states, such as Texas and 

Michigan do not plan to implement such services. States without 511 

services may choose not to establish them because they lack adequate 

traffic data and funding. Furthermore, rather than using 511 services, 

some states may disseminate traffic information using other methods, 

such as the Internet and dynamic message signs. 511 roadside signs, like the one 

shown above, are used to promote 

awareness of the 511 travel service. 

Figure 2: Status of 511 Traveler Information Services, as of September 2009 

Sources: 511 Deployment Coalition (data); MapArt (base map).

Pa.

Idaho

Mont.

Wyo.

Utah

N.Mex.

Colo.

N.Dak.

S.Dak.

Nebr.

Tex.

Kans.

Okla.

Minn.

Iowa

Mo.

Ark.

La.

Ill.

Miss.

Ind.

Ky.

Tenn.

Ala.

Fla.

Ga.

S.C.

N.C.

Va.

Ohio

N.H.

Mass. ( )

Mich.

Wash.

Wis. N.Y.

Maine

Vt.

W.Va.

Hawaii

Designates metropolitan or regional area with 511 service

511 expected to be operational by 2010

511 not expected to be operational by 2010

511 is operational

R.I. ( )

Conn. ( )

N.J. ( )

Del. ( )

Md. ( )

D.C. ( )

Ariz.

Ore.

Alaska

Calif.

Nev.

Cincinnati/

Northern Kentucky

regional area

Eastern

Massachusetts

regional area

Eastern Sierra

regional area

San Francisco Bay

metropolitan area

San Diego

regional area

Sacramento/

Northern California

regional area

St. Louis

metropolitan

area

2 GAO-10-121R Real-Time Traffic Information Systems 
Dissemination 

and Coverage 

Federal Role 

DOT has carried out various 

activities to promote the 

deployment of real-time traffic 

information technologies by state 

and local governments, in addition 

to its efforts to promote 511 

services. For example, 

• DOT distributes information on 

best practices, Intelligent 

Transportation Systems (ITS) 

standards, and lessons learned 

related to the deployment of 

these and other ITS 

technologies. DOT also 

provides some technical 

assistance on ITS. 

Funding Sources 

DOT does not provide funding to 

state and local governments 

specifically for the deployment of 

real-time traffic information 

technologies and systems. 

• The Safe, Accountable, 

Flexible, Efficient 

Transportation Equity Act: A 

Legacy for Users (SAFETEALU) authorizes states to use 

their annual federal-aid 

highway funding for developing 

and implementing these 

technologies and systems. 

(These funds are derived from 

the Highway Trust Fund and 

are provided to the states 

mostly through formula grant 

programs.) 

• States generally finance realtime traffic information 

systems and technologies using 

a combination of federal and 

state funds. However, the 

proportions vary. For example, 

California officials told us that 

they have mainly used state 

funds while Florida officials 

told us that they have mainly 

used federal funds. 

State and Local Agencies Use Other Methods for 

Disseminating Real-time Traffic Information 

• Based on DOT’s most recent surveys of ITS deployment in large 

metropolitan areas (conducted in 2007), state and local agencies in 

these areas disseminated real-time traffic information to the public 

primarily through the Internet, e-mail, television and radio, dynamic 

message signs, and Highway Advisory Radio. 2

• These technologies provided information on traffic incidents, travel 

time, and travel speeds on roads in these metropolitan areas.3 

• Most metropolitan areas disseminated information on traffic 

incidents, and significantly fewer disseminated information on 

travel times and travel speeds. (See table 1.) 

• State and local agencies disseminated information on freeways 

more frequently than on arterial roads.4

 (See table 1.) 

Table 1: Percentage of Metropolitan Areas in Which Incident, Travel Time, and 

Travel Speed Information Was Disseminated to the Public in 2007 

Percentage of metropolitan areas 

Type of information Freeways Arterial roads

Incident 87% 68%

Travel time 36% 19%

Travel speed 32% 16%

Source: GAO analysis of DOT data. 

Note: These percentages are based on responses from state and local agencies in large 

metropolitan areas to DOT surveys on freeway management and arterial management. Ninety-four 

metropolitan areas responded to the freeway management survey in 2007 (about an 89 percent 

response rate), and 102 metropolitan areas responded to the arterial management survey in 2007 

(about a 95 percent response rate). See enclosure III for more information on the surveys. 

• Some states are collaborating to disseminate traffic information 

across states or across multiple agencies within a jurisdiction. For 

example: 

• Northwest Passage Corridor Coalition: Wisconsin, Minnesota, 

North Dakota, South Dakota, Montana, Wyoming, Idaho, and 

Washington coordinate the information they disseminate to the 

public, particularly on interstates that cross multiple states. 

 

2

These surveys reflect ITS deployments by state and local agencies, not 

deployments by private companies. DOT plans to conduct the next survey of ITS 

deployments in 2010. 

3

These technologies may have provided additional types of information, but 

DOT’s surveys asked only about incidents, travel times, and travel speeds.

4

According to DOT officials, the term "freeways," which is used in its ITS 

deployment surveys, refers to controlled access roads that have no intersections. 

Arterial roads generally consist of roads that have signalized intersections.

3 GAO-10-121R Real-Time Traffic Information Systems 
 Dissemination 

and Coverage 

Dynamic message signs, like the 

one shown above, are electronic 

roadside signs displaying traveler 

information that can be updated in 

real time. These signs can provide 

travelers with en route information 

on incident and closures, travel 

times, and traffic and weather 

conditions. 

State and Local Agencies Dissemination Methods (continued) 

Source: DOT.

• Transportation Operations Coordinating Committee 

(TRANSCOM): State and local agencies in New York, New Jersey, 

and Connecticut formed this coalition, which collects and 

disseminates real-time incident and construction information to 

over 100 member agencies and the public in the New York 

metropolitan area. 

• I-95 Corridor Coalition: States along the I-95 Corridor, from 

Maine to Florida, formed this coalition, which provides 

information via a Web site on traffic conditions and travel time. 

Geographic Coverage Provided by State and Local Data 

Collection Technologies Is Limited 

• Although state and local agencies disseminate traffic information 

through various methods, the information available for dissemination 

to the public is limited because the geographic coverage of the 

technologies the agencies deploy within their areas of operations to 

collect traffic data, such as fixed sensors and cameras, is limited. 

• Based on DOT’s 2007 surveys, technologies used by state and local 

agencies for collecting real-time traffic data covered about 39 percent 

of the combined freeway miles in the 64 large metropolitan areas that 

provided this information. 5

 While the percentage is up from 33 

percent reported for 2004, it reveals a significant gap, given tha

freeways account for the majority of the nation’s traffic, congestion, 

and travel time variability. 

The images shown at this traffic 

management center, located in 

Orlando, Florida, were taken from 

traffic cameras. The traffic cameras 

collect real-time traffic data, and 

the center aggregates the data from 

the cameras and from other 

technologies and then disseminates 

relevant traffic information to the 

public. 

Source: Florida Department of Transportation.

t urban 

 

• The cost of deploying and maintaining technologies that collect 

traffic data, such as fixed sensors, is a major factor limiting the 

roadway mileage public agencies can cover. 

• Although DOT does not have comparable information on the 

collection of traffic data for arterial and rural roads, DOT and state 

officials told us that coverage is significantly lower for these roads 

than for freeways. 

• The main factor limiting the collection of accurate data on arterial 

roads is cost because more data collection technologies are 

needed to capture traffic data between the many entrances and 

exits on arterial roads (e.g., for gas stations, shopping centers, and 

buildings). Also, arterial traffic is a greater challenge to measure 

because signalized intersections often interrupt traffic flow and 

make it harder to predict. 

5

While 94 metropolitan areas responded to the 2007 survey on freeway 

management, 30 of these metropolitan areas did not report information on 

technologies for collecting real-time traffic data on their freeways. 

4 GAO-10-121R Real-Time Traffic Information Systems 
5 GAO-10-121R Real-Time Traffic Information Systems 

ENTER HEADER

Dissemination 

and Coverage 

Measures of Data Quality 

Good data quality is needed to 

provide useful information to 

travelers so that they can make the 

most efficient travel decisions. The 

quality of traffic data is determined 

by the data’s timeliness, accuracy, 

and availability. 

• Timeliness—the time from 

when an event or condition 

occurs to when it is reported by 

real-time information 

dissemination technology. 

• Accuracy—how close the 

reported data are to “ground 

truth,” or actual conditions. 

• Availability—how much of the 

data designed to be collected 

by the real-time information 

collection technology is 

actually made available. 

Geographic Coverage is Limited (continued) 

• The coverage in rural areas is lower mainly because the delivery of 

power and communications to real-time traffic detection 

technologies in isolated areas can be cost prohibitive unless there 

is a specific safety demand—such as a high crash rate. 

Additionally, congestion in rural areas is much lower than in 

metropolitan areas, lessening the need for real-time traffic 

information. 

State and Local Agencies Vary in the Quality of the Traffic 

Data They Collect and the Extent to Which They Share Traffic 

Information 

• The quality of real-time traffic data collected, including the data’s 

timeliness, accuracy, and availability, varies by state and local 

government. 

• The timeliness of dissemination to the public depends on the type 

of information disseminated (i.e., incident information, travel 

time) or geographic location (i.e., metropolitan or 

nonmetropolitan area). For example, it may take longer to 

disseminate information in rural areas compared with urban areas 

because state DOTs may not have the available resources or 

infrastructure to collect and report information quickly in rural 

areas. 

• Although a key data collection technology used by public 

agencies—fixed sensors embedded in the roadway—is generally 

accurate, there is variation in how reliably these sensors function. 

In cases where sensors do not function, traffic data are not 

available from them. In California, for example, some districts 

have sensors that function 50 percent of the time, while other 

districts’ sensors function 90 percent of the time. The poor 

reliability of the sensors in some districts is generally due to 

hardware failure, such as broken wiring and missing parts. 

• The extent to which states and local agencies share or exchange data 

and information varies. 

• According to the 511 Deployment Coalition, there are three basic 

ways to transfer and share data or information from 511 systems: 

calls, data transfer, and application or database sharing—23 

services currently transfer calls, 0 transfer data, and 9 share 

applications or databases. (See table 2.) 

• Some states, such as Alaska, Louisiana, Massachusetts, and 

Missouri, do not transfer calls, transfer data, or share databases or 

applications. The main reason these states do not share data, 

particularly through data transfer or database sharing, is that they 

do not want to incur the cost of matching data or developing a 

matching database for two or more systems.
Dissemination 

and Coverage 

State and Local Agencies’ Data Quality and Sharing Vary 

(continued) 

Table 2: Extent to Which 511 Services Share or Exchange Data and Information 

How information and data are shared 

Number of states and 

metropolitan/regional 

areas States and metropolitan/regional areas 

Call transfer 

One 511 system transfers calls to another 511 system.

23 Sacramento, Cincinnati/Northern Kentucky, Colorado, 

Florida, Georgia, Idaho, Iowa, Kansas, Maine, 

Montana, New Jersey, North Dakota, New 

Hampshire, New Mexico, New York, North Carolina, 

South Dakota, Tennessee, Utah, Vermont, Virginia, 

Washington, Wisconsin 

Data transfer 

The underlying data systems are accessible to other 

511 systems, enabling those systems to exchange 

information with neighboring jurisdictions without 

transferring calls. 

0 No states or local agencies transfer data. 

Application or database sharing 

Deployers use the same underlying application to run 

their 511 systems. 

9 Eastern Sierra (California), Iowa, Kansas, Montana, 

New Jersey, North Dakota, Rhode Island, South 

Dakota, Vermont 

Source: GAO analysis of 511 Deployment Coalition data.

6 GAO-10-121R Real-Time Traffic Information Systems 
Dissemination 

and Coverage 

Private Companies Disseminate Traffic Information through 

Newer Technologies 

• Historically, privately operated news and media outlets have 

disseminated traffic information over radio and television broadcasts. 

In recent years, private companies have begun to disseminate traffic 

information through newer technologies such as cell phones, the 

Internet, and navigation devices in vehicles, among others. 

• The services provided by the companies that use these newer 

technologies include 

• e-mail and cell phone alerts about traffic congestion and 

incidents; 

• Web sites that provide various types of traffic information, 

including personalized drive times and live video; and 

• navigation devices (in-vehicle and portable) that can provide 

information on traffic flow and speed, estimated travel times, 

and lane closures, among other things. 

• Some private companies disseminate traffic information directly to 

the public. These companies provide basic traffic information to the 

public for free on Web sites and more detailed information for a fee. 

Some private companies provide traffic information to state and local 

agencies or other private companies, which then disseminate this 

information. 

• Furthermore, some private companies disseminate traffic information 

nationally, mainly in metropolitan areas. Following are examples: 

• Westwood One disseminates real-time traffic information to the 

public nationwide through its affiliations with 2,400 radio stations, 

more than 170 television stations, and more than 250 Web sites. 

• Clear Channel’s Total Traffic Network disseminates real-time 

traffic data in 95 cities via in-car or portable navigation devices, 

broadcast media, and wireless and Internet-based services. 

• NAVTEQ Traffic is available in more than 120 markets across the 

nation. The company disseminates traffic information to the 

public about road construction, traffic speeds, and incidents 

through in-vehicle and personal navigation devices, cell phones, 

and Web sites. NAVTEQ Traffic also provides traffic information 

to other private companies that disseminate information through 

navigation devices. 

• A number of other companies, such as Google and Yahoo!, 

disseminate real-time traffic information—such as traffic flow and 

speed—nationally via Web sites and other means. 

7 GAO-10-121R Real-Time Traffic Information Systems 
Dissemination 

and Coverage 

Federal Role 

DOT is conducting research and 

development to improve traffic 

information coverage by both the 

public and private sectors. 

• Through its Safe Trip-21 

initiative, DOT—in partnership 

with state and local agencies, 

the private sector, and 

academia—is testing the use of 

vehicle probes to generate realtime data and provide travelers 

with current information on 

traffic congestion, roadway 

conditions, and alternative 

travel options. Vehicle probes 

use roaming vehicles and 

portable devices to collect data 

on travel times and speeds. 

Vehicle probes include cell 

phones and Global Positioning 

System (GPS) devices. Test 

sites are being operated in the 

San Francisco Bay area and in 

the I-95 Corridor along the East 

Coast. 

• DOT has also conducted some 

evaluations—such as a recent 

assessment of the current state 

of traveler information—to help 

determine what activities are 

needed to make real-time 

information more accurate and 

complete. 

New Private Sector Data Collection Technologies Are Helping 

to Expand Coverage 

• Private companies are expanding the coverage of information that is 

disseminated by both public and private entities by using new 

technologies to increase the collection of real-time traffic data. 

• Some private companies are using newer technologies, such as 

vehicle probes, to collect real-time data on travel time and speed 

(see fig. 3). These companies are collecting data beyond what 

state and local governments collect. For example, INRIX—a 

company that focuses on collecting and aggregating real-time 

traffic data—collects data using commercial fleet vehicle probes 

and other technologies. An advantage of such technologies is that 

data are collected on arterial roads and other roads where there 

are no fixed collection technologies (such as fixed sensors). 

Figure 3: Vehicle Probe Technology for Collecting Real-Time Traffic Data 

Sources: GAO and the I-95 Corridor Coalition.

2 miles

Wireless signal

detected at

8:04:26 a.m.

Wireless signal

detected at

8:06:58 a.m.

Travel distance (2 miles)

Travel time (.042 hours)

Speed (47.6 MPH)

• Public-private partnerships are expanding data that state departments 

of transportation can use in disseminating real-time traffic 

information. For example, the Alabama department of transportation 

purchased data from INRIX on roughly 125 miles of roads in the 

Birmingham area to generate travel times for dynamic message signs, 

and the state plans to expand its contract to cover the entire state. 

8 GAO-10-121R Real-Time Traffic Information Systems 
 

Dissemination 

and Coverage 

Despite Their Advanced Technologies, Private Companies 

Face Certain Limitations in the Coverage and Quality of Data 

They Collect 

• Private companies face certain limitations in the coverage of data they 

collect. Some examples are as follows: 

• Market disincentives (e.g., little demand for real-time traffic 

information) discourage private companies from collecting data 

on and disseminating information about rural roads and minor 

arterials. 

• Data collected by vehicle probes in commercial fleets depend on 

where these fleets travel. More specifically, some commercial 

fleets, such as delivery companies and taxicabs, may travel only 

on assigned routes or may not travel on freeways. 

• Some state departments of transportation require that private 

companies pay for access to public data. However, some private 

companies told us that although such data could enhance their 

coverage, they often have chosen not to pay for access because 

the data are not of high enough quality to merit payment. 

• The quality of data collected using the newer technologies has the 

following limitations: 

• Data from vehicle probes, such as GPS devices and cell phones, 

may not be collected from enough vehicles to achieve the sample 

size required for accuracy. 

• Some commercial fleets avoid travel during peak periods. As a 

result, probe data collected from these fleets may not accurately 

reflect traffic or travel conditions during peak periods. 

• Furthermore, the public sector may not be able to determine the 

quality of real-time traffic information it receives from private 

companies because (1) it may have limited access to the underlying 

data that is collected and aggregated by these companies and (2) the 

methods these companies use to collect and aggregate the data may 

be proprietary. 

9 GAO-10-121R Real-Time Traffic Information Systems 
DOT Has Proposed a Program That Has 

Potential Benefits, but Some Stakeholders Are 

Concerned about Time Frames and Costs 

DOT’s Actions 

SAFETEA-LU Requirements 

In 2005, Section 1201 of SAFETEALU required that the Secretary of 

Transportation establish a program 

to provide all states the capability 

to 

• monitor, in real-time, the traffic 

and travel conditions of major 

highways, and 

• share that information to 

facilitate national and regional 

highway traveler information, 

among other things. 

SAFETEA-LU did not include a 

deadline for the Secretary to 

establish this program. 

SAFETEA-LU does not provide 

separate funding to implement this 

program. However, Section 1201 of 

SAFETEA-LU authorizes states to 

use their annual federal-aid 

highway funds provided through 

the Highway Trust Fund to fund 

implementation of this program, as 

well as other ITS projects. 

DOT Has Proposed a Program that Aims to Improve Traffic 

Information Coverage, Quality, and Sharing 

• To fulfill requirements in SAFETEA-LU, the Federal Highway 

Administration (FHWA) issued a Notice of Proposed Rulemaking in 

January 2009 to establish the Real-Time System Management 

Information Program.6

 The proposed rule contains minimum 

requirements for states to make information on traffic and travel 

conditions available through real-time information programs and to 

share this information. 7

• FHWA currently plans to issue a final rule in February 2010.8

 

• The proposed rule aims to create general uniformity among real-time 

information programs to ensure consistent service to travelers and 

other agencies. It also aims to improve the availability of information, 

which could lead to the dissemination of more information to 

travelers by public agencies and private companies, as well as to 

better traffic control by public agencies, among other things. 

• The proposed rule requires states to make certain information 

available on all interstates9

within 2 years and on selected 

metropolitan-area, noninterstate “routes of significance” within 4 

years. 10 (See table 3.)

• States that do not currently collect this information will have to select 

an approach to achieve compliance from a variety of options, 

including installing data collection technologies or contracting with 

private companies to obtain the data, thus improving real-time traffic 

information coverage. These requirements could also provide a basis 

for the development of a new 511 service in states that do not provide 

this service because they lack sufficient data. 

 

6

See 74 Fed. Reg. 1993 (Jan. 14, 2009). 

7

According to DOT’s benefit-cost analysis of the Real-Time System Management 

Information Program, the present value of the total cost for establishing real-time 

information programs in all states and the nation’s 50 largest metropolitan areas 

and operating these programs through 2018 would be about $1.2 billion. See 

enclosure II for more details on this analysis. 

8

Before the rule is finalized, it will have to be reviewed by the Office of the 

Secretary at DOT and by the Office of Management and Budget. 

9

Interstate highways are routes designated as part of the Dwight D. Eisenhower 

National System of Interstate and Defense Highways. 

10The proposed rule notes that states should select routes of significance based 

on various factors, including their importance for congestion relief, disaster 

evacuation, economic growth, and safety. 

10 GAO-10-121R Real-Time Traffic Information Systems 
DOT’s Actions 

Proposed Program (continued) 

Table 3: Types of Information Required on Interstate and Selected Noninterstates, in Metropolitan and Nonmetropolitan 

Areas 

Interstates 

(implement within 2 years) 

Selected noninterstates 

(implement within 4 years) 

Type of information required 

Metropolitan 

areas 

Nonmetropolitan 

areas 

Metropolitan 

areas 

Nonmetropolitan 

areas 

Roadway or lane closures due to construction activities 9 9 9 Not required 

Roadway or lane closures due to traffic incidents 9 9 9 Not required 

Roadway weather conditions 9 9 9 Not required 

Travel time along highway segments 9 Not required 9 Not required 

Source: GAO analysis of DOT information. 

Note: Metropolitan areas refer to geographic areas with populations over 1 million, designated as Metropolitan Statistical Areas by the Office of 

Management and Budget. The proposed rule noted that, as of December 31, 2006, 49 metropolitan areas had populations over 1 million. 

• The proposed rule indicates that all state real-time information 

programs that are funded in whole or in part through the Highway 

Trust Fund would be subject to its requirements and that states would 

need to demonstrate compliance prior to authorization of funds for 

ITS projects. 

• According to FHWA officials, the agency’s division offices, one of 

which is located in each state, will monitor compliance and will 

work closely with any states that are facing challenges and allow 

them flexibility. FHWA plans to provide states with additional 

guidance to help them meet requirements. 

• The proposed rule also establishes minimum data quality 

requirements for the information that states are required to make 

available. Specifically, the rule establishes minimum requirements for 

timeliness, availability, and accuracy. (See table 4.) 

• To the extent that states adhere to these requirements, they should 

improve data quality nationwide or at least improve the quality of 

data from those entities that do not already meet those minimum 

requirements. 

11 GAO-10-121R Real-Time Traffic Information Systems 
DOT’s Actions 

Proposed Program (continued) 

Table 4: Timeliness, Availability, and Accuracy Requirements for Real-Time Traffic Information in Proposed Rule 

Requirements 

Type of information required 

Timelinessa for metropolitan 

areas 

Timeliness for nonmetropolitan 

areas 

Availability b Accuracy c

Roadway or lane closures due to 

construction activities

10 minutes 20 minutes 90% 85%

Roadway or lane closures due 

traffic incidents

10 minutes 20 minutes 90% 85%

Roadway weather conditions 20 minutes 20 minutes 90% 85%

Travel time along metropolitan area

highway segments

10 minutes Not required 90% 85%

Source: DOT. 

a

Timeliness requirements refer to the time it takes to deliver the information. b

Availability requirements refer to the percentage of time that the information is expected to be available, at a minimum, based on the design of the 

real-time information program. c

Accuracy requirements refer to the percentage of time that the information is expected to be accurate, at a minimum, based on the design of the realtime information program. 

• The proposed rule allows states flexibility in how they will meet the 

requirements. 

• There is no requirement for a state or other entity using federal 

funds to apply any particular technology in collecting the data 

necessary to fulfill the program’s specifications. For example, 

states may use their existing fixed sensors to collect data on travel 

times on highway segments. 

• States may use any business approach to establish a real-time 

information program. For example, states can collect data on 

their own, contract with the private sector to collect all or some of 

the data, or purchase information products from the private 

sector. 

• States can employ any technology for disseminating information. 

States could continue to provide information through 511 services 

or state Web sites. Additionally, FHWA encourages states to 

partner with the private sector to disseminate to the public 

information that is made available under the proposed rule. 

12 GAO-10-121R Real-Time Traffic Information Systems 
13 GAO-10-121R Real-Time Traffic Information Systems 

DOT’s Actions 

SAFETEA-LU Requirements 

SAFETEA-LU also required the 

Secretary of Transportation to 

establish data exchange formats 

within 2 years of the act’s 

enactment to facilitate the sharing 

of data on traffic and travel 

conditions across jurisdictional 

boundaries and the availability of 

such information nationwide. 

SAFETEA-LU further required 

states to incorporate the data 

exchange formats established by 

DOT into their traffic and traveler 

information systems but did not 

specify a deadline for states’ use 

of these formats. 

DOT Has Proposed Guidance on Data Exchange Formats 

• To fulfill SAFETEA-LU requirements, in 2007, FHWA issued interim 

guidance on the use of standard formats for exchanging data on traffic 

and travel conditions. These formats, to the extent that states utilize 

them, allow the data collected by a state to be available to any other 

state or jurisdiction that wants to retrieve the data in the same format. 

FHWA plans to finalize the data exchange format guidance after the 

Real-Time System Management Information Program regulations are 

finalized in early 2010. 

• Once finalized and adopted by states, the guidance would support 

the proposed Real-Time System Management Information 

Program by making it easier for states and jurisdictions to share 

the basic real-time traffic information the program requires. The 

exchange formats in the guidance link the proposed program 

requirements to specific ITS standards for data exchange.11 To the 

extent that states use these formats and incorporate these ITS 

standards, information will be easier to exchange across multiple 

jurisdictions. 

• According to DOT officials, although states are required under 

SAFETEA-LU to incorporate the data exchange formats, DOT does 

not plan to require states to use them in the near term because the ITS 

standards on which the formats are based are still under development. 

• DOT officials said that the department could adopt the ITS 

standards referenced in the data exchange format guidance when 

these standards are finalized, and DOT could then require states to 

use them.12 However, DOT has no plans to adopt the standards at 

this time. 

• DOT has not obtained information on what data exchange formats 

states use since its 2004 surveys of ITS deployments in large 

metropolitan areas, but agency officials said that they may obtain this 

information in their next ITS deployment survey effort in 2010. 

Furthermore, according to DOT officials, the agency’s division offices 

will monitor how well states are following the data exchange format 

guidance. 

 

11ITS standards define how ITS systems, products, and components can be 

interconnected and exchange information, among other things. Many ITS 

standards are consensus-based, meaning that all interested parties agreed, 

through cooperation and compromise, on the published standard. 

1223 C.F.R. § 940.11(f) requires that all ITS projects funded through the Highway 

Trust Fund use applicable DOT-adopted ITS standards. For DOT to adopt ITS 

standards, it must first issue a rule, but it has not yet done so for any of these 

standards. 
DOT’s Actions 

 Stakeholders Have Cited Benefits of the Proposed Program 

• State and local officials,13 as well as private sector representatives, 

have cited a number of potential benefits of the program. 

• Most state and local government officials and private sector 

representatives we interviewed said that improved coverage and 

information sharing would provide travelers more information so 

that they have the opportunity to choose the most efficient route 

to reach their destination, thus providing the opportunity to 

reduce congestion and obtain potential benefits to the 

environment, the economy, and disaster evacuation efforts. 

• Some private companies that submitted comments on the 

proposed rule said that the program would advance the data 

collection market and would provide them with additional 

opportunities to fill gaps in public agencies’ data collection. 

State and Local Stakeholders Have Cited Time Frames and 

Costs as Challenges in Implementing the Proposed Program 

• Most state and local government officials that we interviewed cited 

challenges in implementing the program within the specified time 

frames and said that the program would be difficult to implement 

without additional funds. Because some states and local governments 

are facing budget constraints, the implementation of a real-time 

information program may not be a priority. 

• According to some state and local transportation agencies that 

submitted comments to the proposed rule, the proposed requirements 

may not take into account local needs and could be challenging to 

implement even for states with existing 511 services. For example, 

the Metropolitan Transportation Commission, which operates San 

Francisco Bay Area’s 511 service, said that there is little need for 

roadway weather information in areas of the country where weather 

does not significantly affect travel. Furthermore, Kansas noted that it 

would be challenging for them to collect certain traffic data, such as 

on incidents in rural areas, because they may have limited or no 

resources or infrastructure in these areas to collect this data and 

report it to their statewide 511 service. 

• DOT is currently considering options to address stakeholders’ 

concerns as it finalizes the program’s requirements. We are not 

making recommendations to DOT about the Real-Time System 

Management Information Program at this time because the agency’s 

efforts to establish the program are still in the preliminary stages. 

 

13Some local agencies have agreements with their respective state departments of 

transportation to collect, aggregate, and disseminate real-time traffic information 

to the public. Under such agreements, some local governments may support the 

state departments in implementing the requirements of the Real-Time System 

Management Information Program. 

14 GAO-10-121R Real-Time Traffic Information Systems 
Most Selected Experts Said a Nationwide 

System Is Needed, but Their Visions of Such a 

System Varied 

Nationwide 

System 

Mobility improvements are 

typically measured in terms of 

decreases in delay and travel time, 

and improvements to the 

environment are measured by 

decreases in emissions and fuel 

consumption. See enclosure II for 

examples of studies that discuss 

the impact of real-time traffic 

information systems and 

technologies on mobility and the 

environment. 

Most Experts Saw a Need for a Nationwide System 

Seventeen of the 19 experts we interviewed said that a need exists for the 

development of a nationwide real-time traffic information system. 

• Some of these 17 experts noted that current approaches to developing 

real-time traffic information systems are fragmented because state 

and local transportation agencies generally develop and use these 

systems within their own jurisdictions, leading to gaps in coverage 

and inconsistencies in the quality and types of data collected. 

• Many of these experts emphasized that, in their view, information 

coverage would be expanded and data quality improved under the 

nationwide system they envisioned, resulting in benefits for 

mobility and the environment beyond existing real-time traffic 

information systems. 

• Some experts also said that they believe that further 

enhancements in the sharing of information under a nationwide 

system could provide potential benefits to the economy and 

improve coordination of emergency response efforts that might 

not be realized under existing state or regional systems. For 

example, improved information sharing could allow commercial 

truckers to better plan their interstate trips and, in turn, reduce 

delivery times or make delivery times more reliable. It also could 

allow multijurisdictional areas to communicate better prior to, 

during, and after an emergency. 

Two of the 19 experts we interviewed, however, said that they saw no 

need for the development of a nationwide system. 

• One said that there was no need, in part, because adjoining states or 

jurisdictions that need to share information have already developed 

methods for doing so, such as states that are a part of the I-95 

Corridor Coalition. This expert said that multiple regional systems 

across the nation would be sufficient. 

• The other said the benefits of such a system would not be sufficient to 

justify the level of investment that would be needed to develop it. 

15 GAO-10-121R Real-Time Traffic Information Systems 
Nationwide 

System 

For the purposes of this review, 

current efforts that some may see 

as leading to a nationwide real-time 

traffic information system include 

• DOT’s efforts to establish the 

Real-Time System Management 

Information Program; 

• state and local transportation 

agencies’ efforts to expand 

coverage of 511 Traveler 

Information Services; and 

• the private sector’s efforts to 

collect, aggregate, and 

disseminate real-time traffic 

information across the nation. 

Most of these 10 experts envisioned 

little change in the roles of state 

and local transportation 

agencies—that is, the agencies 

would continue to deploy, or 

partner with other public agencies 

or private companies to deploy, 

real-time traffic information 

technologies that collect, aggregate, 

and disseminate real-time traffic 

information. 

Experts Views on Need for a Nationwide System (continued) 

The 17 experts that said there was a need for a nationwide system had 

varying views on the type of nationwide system that is needed (see fig. 4). 

• Seven of these 17 experts either envisioned a nationwide system that 

would be similar to the anticipated results of current efforts by DOT, 

state and local transportation agencies, and the private sector or said 

that current efforts are already leading to a nationwide system. 

• Ten of these experts envisioned a nationwide system that would go 

beyond current efforts, such as a system creating a national user 

interface for disseminating information, but these visions varied. 

• Some experts said that current efforts are not sufficient to develop 

a nationwide system. For example, one expert noted that DOT’s 

proposed rule on the Real-Time System Management Information 

Program would actually create statewide systems, rather than a 

nationwide system. 

Figure 4: Views of Experts on Whether a Nationwide Real-Time Traffic Information 

System Is Needed and Whether Such a System Should Go Beyond Current Efforts 

Visions of a Nationwide System beyond Current Efforts Varied 

The 10 experts that envisioned the development of a nationwide system 

beyond current efforts had varying views on the appropriate level of 

involvement for DOT and the private sector, as well as on the form a 

nationwide system could take. Among the aspects of a nationwide system 

envisioned by these experts are a strong leadership role by DOT, 

increased DOT partnerships with the private sector, and a national 

interface for disseminating information. These differing aspects are not 

necessarily mutually exclusive. For example, DOT could both take a 

strong leadership role and partner with the private sector to collect, 

aggregate, and disseminate real-time traffic information. 

16 GAO-10-121R Real-Time Traffic Information Systems 
Nationwide 

System 

DOT is currently developing an ITS 

strategic plan that will identify the 

direction of the department’s ITS 

program over the next 5 years. 

DOT has sought stakeholders’ 

views in developing this plan, 

including views on what its role in 

real-time traffic information 

systems should be. Some have 

called for DOT to strengthen its 

role in this area. For example, one 

stakeholder commented that it is 

critical for DOT to develop a 

variety of standards and guidelines 

for data exchange and for those 

standards to be adopted by public 

and private stakeholders. 

Visions Varied (continued) 

• Strong leadership role by DOT—A few experts envisioned that DOT 

would play a strong leadership role in a nationwide system, 

specifically by developing and enforcing requirements and providing 

funding for state and local transportation agencies to develop and 

maintain real-time traffic information systems. 

• Some experts said that DOT should take a strong role in 

developing and enforcing requirements for the types of 

information to be collected and disseminated, data quality, and 

common data exchange formats, as well as ITS standards. For 

example, by ensuring compliance with its new requirements under 

the Real-Time System Management Information Program, DOT 

could help ensure consistency in the types of information 

collected and in the quality of the data.14 In addition, one expert 

said that DOT’s reluctance to require that states use ITS standards 

will dilute the effectiveness of those standards.15

• Although SAFETEA-LU does not provide separate funding for 

states to implement the Real-Time System Management 

Information Program, several experts said additional funding is 

necessary to develop a nationwide system. One expert envisioned 

DOT as a grant-giver or funder of real-time traffic information 

programs. In this vision, by directly funding such programs, DOT 

could better set and enforce requirements that could improve data 

coverage, quality, and sharing. 

• Other experts said that DOT could act more like the operator of a 

nationwide system. For example, DOT could enter into and 

manage agreements with the private sector to collect and 

disseminate a base level of real-time traffic information 

nationwide. Or DOT could develop and operate a national user 

interface—such as a phone number or Internet page—that a 

traveler, regardless of location, could call or access to obtain, or 

be directed to, relevant information. 

 

14The proposed rule states that FHWA will monitor compliance and may decline 

to approve federal-aid projects, pursuant to 23 C.F.R. § 1.36, if a state does not 

comply with the regulations. 

15DOT, through cooperative agreements with six standards development 

organizations such as the Institute of Transportation Engineers, helps to develop 

nonproprietary, industry-based, consensus ITS standards. As noted previously, 

DOT may adopt ITS standards and require states to follow them by issuing a rule, 

but DOT has not yet done so. 

17 GAO-10-121R Real-Time Traffic Information Systems 
Nationwide 

System 

Visions Varied (continued) 

• Increased partnerships with the private sector—While some private 

companies currently partner with state and local transportation 

agencies, several experts envisioned a nationwide system that would 

have even more private sector involvement. Some of these experts 

noted that the private sector is using more advanced technology and 

that a nationwide system should take advantage of this innovation. 

Examples are as follows: 

• Two experts envisioned a private company contracted by either 

DOT or state and local transportation agencies. In the first vision, 

DOT would contract with a private company, and the single 

contract with DOT could help ensure the collection of consistent 

data nationwide. In the second vision, which would replicate the 

I-95 Corridor Coalition’s business model on a national level, state 

and local transportation agencies within a region would jointly 

contract with a single private company to collect and aggregate 

data and translate the data into real-time traffic information. The 

state and local transportation agencies would disseminate the 

information to the public and might also collect and disseminate 

additional information beyond the data provided to the region 

under the private contract. 

• Another expert envisioned that DOT would contract with several

private companies to collect and aggregate data on behalf of state 

and local transportation agencies. In this vision, the private sector 

would perform most operations needed to support the nationwide 

system, and DOT would establish data quality standards and other 

specific requirements, such as requirements to ensure consistency 

in the information collected and disseminated. Information could 

be disseminated to the public by either or both entities. 

• National user interface for disseminating information—While the 

current 511 phone number could serve as a national user interface, 

511 Traveler Information Services are not available in all states, and 

the various state and regional services do not provide consistent 

information. Two experts envisioned a nationwide system—possibly 

operated by the federal government or the private sector—that would 

disseminate information through a public user interface, such as a 

common phone number or Web site. This public user interface would 

provide consistent information and would be accessible to travelers 

from anywhere in the nation, at any time. 

18 GAO-10-121R Real-Time Traffic Information Systems 
Nationwide 

System 

Visions Varied (continued) 

• One expert envisioned a national phone system that would receive 

calls centrally and disseminate information to travelers to allow 

state and local agencies to focus their resources on data collection 

without having to support all the technology required for 

information dissemination. Another expert envisioned multiple 

national interfaces managed by both the public and private 

sectors. For example, while state and local transportation 

agencies could operate a nationwide user interface that would 

provide a base level of real-time traffic information, private 

companies could operate another national phone number, Web 

site, or other service that would provide more personalized 

traveler information, but might also require that travelers pay a fee 

for that information. A centralized interface could help ensure 

consistency in the types of data collected and in data quality. 

Experts Held Similar Views on Needed Nationwide Coverage 

Although experts varied in their views on the form a nationwide system 

could take, most said that a nationwide system should, at a minimum, 

cover controlled access roads, such as interstates, in both urban and rural 

areas. These experts also said that the nationwide system should cover 

some key arterial roads. 

• One expert noted that information for every road all the time would 

be ideal but not feasible. 

• Some experts said that while a nationwide system should cover at 

least interstates and other controlled-access roads and some key 

arterial roads, the types of information collected and disseminated 

could vary depending on the characteristics of the road—controlled 

access versus arterial and low volume versus high volume. 

19 GAO-10-121R Real-Time Traffic Information Systems 
Nationwide 

System 

Experts Cited Challenges in Designing and Implementing a 

Nationwide System 

Some experts predicted that reaching consensus on the form of a 

nationwide system and the roles of the public and private sectors could be 

a major challenge. 

• Some experts noted that state and local transportation agencies prefer 

to maintain control over efforts within their borders. Thus, a design 

that dramatically changed the role or shifted the level of control or 

responsibility from the state and local levels to the federal level or to 

the private sector could meet with resistance from states and 

localities. 

• Some experts noted that difficulties in quantifying the benefits and 

costs of such a system would make it challenging to determine the 

most cost-effective design.16 See enclosure II for results of studies 

that conducted benefit-cost analyses of real-time traffic informat

systems and the challenges in conducting such analyses. 

ion 

 

Experts also cited several potential challenges to implementing a 

nationwide system that they said would need to be addressed. 

• The most common implementation challenge cited by the experts was 

the availability of funding. As previously discussed, some state and 

local agencies are already anticipating significant challenges in 

implementing DOT’s proposed Real-Time System Management 

Information Program because of budget constraints. Any additional 

modifications, such as in the format for collecting data or 

disseminating information, could be a challenge for state or local 

agencies, given resource constraints. 

16If DOT were to issue a rule on a nationwide real-time traffic information system, 

a regulatory benefit-cost analysis could be required to comply with Executive 

Order 12866 and the Unfunded Mandates Reform Act of 1995. Executive Order 

12866 directs agencies to conduct economic analyses of significant regulatory 

actions and to select the policy that maximizes net benefits to society unless a 

statute requires otherwise. The Unfunded Mandates Reform Act of 1995 requires 

agencies to choose the least costly, most cost-effective, or least burdensome 

option, unless inconsistent with law or the agency head explains why this option 

was not adopted. 

20 GAO-10-121R Real-Time Traffic Information Systems 
Nationwide 

System 

Experts Cited Challenges (continued) 

• Other implementation challenges cited by experts included 

• the need for a clear and sustained vision; 

• the need to ensure consideration of local area needs; 

• limited staff expertise, such as states’ limited knowledge of 

emerging technologies; 

• limited understanding of the data quality needed to provide useful 

information to travelers and of how to measure this quality; and 

• limited public awareness and use of traffic information.17

A few experts noted, however, that resistance to change and funding 

challenges could be minimized if a nationwide system were built on 

existing efforts or systems, such as 511 Traveler Information Services. In 

their view, a nationwide system that significantly changed existing efforts 

or systems would meet with resistance and require more resources. 

The above viewpoints may provide information that is useful to 

policymakers as they consider the future direction of federal efforts 

related to real-time traffic information systems. We are not making 

recommendations on this topic at this time, however, because there is no 

clear consensus among the experts we consulted on whether an increased 

federal role in this area is appropriate or what this role might be. 

 

17Some of these challenges currently exist for real-time traffic information 

systems and could continue to be challenges for a nationwide system. 

21 GAO-10-121R Real-Time Traffic Information Systems 
22 GAO-10-121R Real-Time Traffic Information Systems 

Enclosure II 

Studies Found Positive Impacts of Real-Time 

Traffic Information Systems or Technologies 

and Identified Costs 

Impacts and 

Costs 

We conducted a literature review to 

identify studies from 2004 onward 

on the impacts (on mobility, the 

environment, and the economy) 

and costs of real-time traffic 

information systems and 

technologies. Specifically, we 

targeted our literature search to a 

few literature databases, including 

the Transportation Research 

Information Services database—a 

bibliographic database on 

transportation issues. We also 

searched DOT’s ITS Benefits and 

Costs databases, which are publicly 

available. We reviewed the 

methodologies of studies identified 

as relevant to this report and 

determined that they were 

sufficiently reliable. See enclosure 

III for more details on our 

objectives, scope, and 

methodology. 

 

Studies Found Improvements to Mobility and the 

Environment, but Results Are Not Generalizable 

• Studies we reviewed that quantified the impact of real-time traffic 

information systems or technologies found that these systems or 

technologies improved mobility and the environment.18 Some of these 

studies evaluated real-time traffic information technologies 

specifically, while others evaluated the technologies as part of an 

overall ITS. 

• For example, a study of a traveler information system—consisting 

of various technologies that collect, aggregate, and disseminate 

information on traffic and travel conditions—for a freeway 

network in Los Angeles, California, found that deploying this 

system decreased travel time by up to 14 percent. See table 5 at 

the end of this enclosure for more details on this study, as well as 

the results of other studies we reviewed. 

• The quantitative impacts of these studies are not generalizable or 

comparable because these studies are generally specific to a 

particular city or road network and evaluate a specific system or 

technology. 

• Few of the studies we reviewed found negative impacts associated 

with these systems. One study, however, found that traveler 

information systems that recommend alternative routes (such as 

dynamic message signs) may, in some cases, cause congestion on 

these alternative routes. As a result, a traveler may not experience the 

intended travel time reduction. 

No Studies Quantified Impacts on the Economy 

• We did not identify any studies that quantified the impacts of real-time 

traffic information systems and technologies on the economy, such as 

on the nation’s gross domestic product (GDP). 

• However, to the extent that real-time traffic information systems and 

technologies reduce congestion and improve mobility, there may be 

economic benefits. 

• According to the Texas Transportation Institute, in 2007, the cost 

of congestion to the nation’s urban economy was about $87 

billion.19 

• Some private sector representatives we interviewed told us that, 

based on their observations, real-time traffic information technologies 

can foster economic expansion by speeding the delivery of people, 

goods, and services. 

 

18Mobility improvements are typically measured in terms of decreased delay and 

travel time, and environmental improvements are measured by decreased 

emissions and fuel use. 

19Schrank and Lomax. 
23 GAO-10-121R Real-Time Traffic Information Systems 

Impacts and 

Costs 

In its ITS Benefits and Costs 

databases, DOT compiles and 

summarizes studies on the benefits 

and costs of ITS, including realtime traffic information systems. In 

addition to providing summaries of 

studies, DOT’s ITS Costs database 

also provides information on the 

capital, operations, and 

maintenance costs associated with 

individual ITS technologies, 

including those such as video 

surveillance cameras and dynamic 

message signs that can be used to 

collect or disseminate traffic 

information. 

Studies Have Found That Costs Vary with a Range of Factors 

• The costs to deploy, operate, and maintain real-time traffic 

information systems and technologies vary based on a range of factors 

including the size, complexity, usage, coverage, and content provided, 

among other things. 

• For example, a case study published by the 511 Deployment 

Coalition in 2006 summarized the costs of six statewide 511 

services. Of the 511 services reviewed, Virginia’s had the largest 

total cost (about $5.2 million) and Kansas had the smallest total 

cost (about $990,000).20 See table 5 for examples of other studies 

that documented the costs associated with real-time traffic 

information systems and technologies. 

• According to a draft study conducted for DOT, the costs of 

technologies and systems that disseminate real-time traffic 

information, such as 511 systems, can be more easily measured and 

tracked than the costs of technologies and systems that collect and 

aggregate data. 

• The costs of technologies used to collect and aggregate data are 

more difficult to isolate because the infrastructure supports 

multiple operations, including traffic and incident management 

operations. 

 

20The costs of the two services varied because Virginia’s 511 service covered 

many roads within the state, and because the state collected data and ensured 

data quality 7 days a week. By contrast, Kansas’ 511 service shared 

infrastructure with several other states, which may have contributed to its lower 

cost. 
Impacts and 

Costs 

Studies That Conducted Benefit-Cost Analyses Found That 

Benefits Outweighed Costs 

• Of the 20 studies we reviewed, 8 of these studies compared the 

benefits with the costs. 

• The 8 studies that included a benefit-cost analysis found that the 

benefits were greater than the costs. See table 5 for examples of 

studies that included benefit-cost analyses. 

• A majority of these 8 studies evaluated real-time traffic 

information technologies as part of a larger system, such as an 

Intelligent Transportation System. 

• One study—DOT’s analysis of the Real-Time System Management 

Information Program—conducted a benefit-cost analysis of a 

national real-time information program.21 As noted previously, 

this program contains minimum requirements for all states to 

make information available on traffic and travel conditions via 

real-time information programs. 

 

• This study found that the present value of total cost savings 

(about $30.2 billion) due to benefits to mobility, the 

environment, and safety would be greater than the present 

value of the costs (about $1.2 billion) to establish and operate 

the program. See table 5 for more details. 

21DOT prepared a benefit-cost analysis of the Real-Time System Management 

Information Program to satisfy Executive Order No. 12866 and the Unfunded 

Mandates Reform Act of 1995. 

24 GAO-10-121R Real-Time Traffic Information Systems 
Impacts and 

Costs 

Impacts that are simulated use 

assumptions about traveler 

behavior. However, travelers’ 

actual responses to information 

may differ from the assumed 

responses used in the estimate. For 

example, travelers may choose not 

to change their travel plans despite 

receiving information about heavy 

congestion. Or, drivers who switch 

to other modes of transportation 

after receiving information on 

roadway congestion may later 

decide to switch back to driving on 

these roadways. 

Efforts to Determine Impacts and Conduct Benefit-Cost 

Analyses Pose Challenges and May Have Limitations 

• It is challenging to determine the comprehensive impacts and conduct 

benefit-cost analyses of real-time traffic information systems and 

technologies. Furthermore, although studies quantify benefits 

associated with these systems and technologies, these studies may 

have limitations that affect the certainty of the results. Specifically, 

challenges and limitations exist with capturing data, isolating impacts, 

and simulating impacts. 

• Capturing data. It is challenging to capture data about travelers 

and their responses to real-time information, particularly since 

some travelers may receive information anonymously anywhere, 

at any time (e.g., through the radio or through the Internet). 

• Isolating impacts. It is challenging to isolate the quantitative 

impacts of real-time traveler or traffic information systems 

because external factors can influence evaluation outcomes. As 

we have previously reported, once transportation investments are 

completed, they become part of an entire transportation system 

and, therefore, the effects of the individual project become 

difficult to isolate, evaluate, and attribute to the individual 

project.22

• Simulating impacts. Many of the estimated impacts of real-time 

traffic information systems or technologies are simulated. One 

limitation of using simulation methodologies to quantify impacts is 

that the methodologies depend on simplified assumptions—such 

as about traveler behavior—and therefore, the simulated 

outcomes may differ from actual outcomes. 

DOT Is Considering Research on Impacts and Is Encouraging 

Benefit-Cost Analyses 

• DOT is considering a variety of research programs and activities for 

inclusion in its ITS strategic plan, which it expects to issue in early 

2010. As part of the strategic planning process, DOT has sought input 

from stakeholders on ITS research needs. 

• One stakeholder group, the American Association of State 

Highway and Transportation Officials (AASHTO), noted to DOT 

that there is a need to identify and document the benefits of realtime information for mobility and the environment, as well as for 

safety, particularly since collecting and analyzing this information 

can be costly for most states. 

 

22GAO, Highways and Transit Investment: Options for Improving Information 

on Projects’ Benefits and Costs and Increasing Accountability for Results, GAO05-172 (Washington, D.C.: Jan. 24, 2005). 

25 GAO-10-121R Real-Time Traffic Information Systems 
Impacts and 

Costs 

DOT Research on Impacts and Benefit-Cost Analyses 

(continued) 

• DOT officials told us that research that addresses mobility 

impacts, or impacts on the environment and the economy, of realtime traffic information systems and technologies is being 

considered for inclusion in the strategic plan. 

• In response to our 2005 recommendation that DOT encourage costeffectiveness analyses, as well as benefit-cost analyses of ITS, 

including real-time traffic information systems,23 DOT has 

• included benefit-cost analyses of ITS deployments in a database 

on ITS benefits that DOT makes available on its Web site, and 

• promoted a software program—in a guide on resources and tools 

for state and local planners—that can be used to evaluate the 

benefits and costs associated with ITS investments, including realtime traffic information systems and technologies. 

 

23GAO-05-943. 

26 GAO-10-121R Real-Time Traffic Information Systems 
27 GAO-10-121R Real-Time Traffic Information Systems 

Table 5: Examples of Studies That Quantified Benefits of Real-Time Traffic Information Programs, Systems, or 

Technologies; Identified Costs; or Conducted Benefit-Cost Analyses 

City or road 

network 

evaluated/year 

study published 

Program, system, or 

technology 

evaluated Benefits Costs Benefit-cost analysis 

Road network in 

Irvine, California; 

2004 

Traveler information 

system 

Mobility 

Savings in travel time of 

around 5 percent during 

morning peak hours (5:45 

a.m. to 10 a.m.), assuming 

that 15 to 20 percent of 

travelers followed 

instructions of the traveler 

information system. 

Decrease in the average 

time to clear incidents by 7 

minutes, based on historical 

data. 

Information not available. Information not available. 

Freeway network 

in Los Angeles, 

California; 2006 

Traveler information 

system 

Mobility

Savings in travel time of up 

to 14 percent. Travel time 

savings were larger during 

the evening peak hours

(4:00 p.m. to 7:00 p.m.). 

Decrease in travel time 

variability of up to 50 

percent, depending on the 

type of information. 

Information not available. Information not available. 

A construction 

work zone on an 

Interstate in 

Devore, California; 

2006 

Sensor to collect 

travel time data, 

software to estimate 

travel time, dynamic 

message signs, and a

Web site 

Mobility 

Decreased traffic volumes

during weekday peak-hour 

traffic in the work zone, 

causing a reduction in traffic 

delay from an expected 90 

minutes to an actual 50 

minutes. Traffic volumes on 

neighboring freeways

increased but the increase in 

travel time on these roads

was insubstantial. 

The total cost of leasing and 

maintaining the technologies

and of analyzing the data

was about $0.2 million. 

See table note below. 

Arizona, North 

Carolina, Utah, 

Virginia, Kansas, 

and Washington; 

2006 

Statewide 511 

services

Information not available. On average, the statewide 

511 services cost $2.5 

million to design, implement, 

and operate and maintain for 

1 year. Virginia had the 

largest total cost (about $5.2 

million), and Kansas had the 

smallest total cost (about 

$990,000). 

Information not available. 

U.S. highway in a

rural area north of 

Spokane, 

Washington; 2004 

Environmental sensor 

stations that collect 

and transmit road 

weather data, video 

surveillance cameras, 

and Highway 

Advisory Radio 

Information not available. The total cost to construct 

and install these 

technologies was $446,807. 

Information not available. 
City or road 

network 

evaluated/year 

study published 

Program, system, or 

technology 

evaluated Benefits Costs Benefit-cost analysis 

Tucson, Arizona; 

2005 

(a forecast for the 

year 2025)a

ITS—consisting of 35 

technologies

including Highway 

Advisory Radio, 

dynamic message 

signs, a telephoneand Web-based 

traveler information 

system, and kiosks. 

Mobility 

Expected decrease in delay 

due to recurring congestion 

by about 6 percent, 

expected decrease in 

incident-related delay by 

more than 70 percent on 

freeways, and expected 

decrease in annual travel 

time by 7 hours per resident. 

Environment 

Expected reduction in 

annual fuel use by 11 

percent and expected 

reduction in annual carbon 

monoxide, hydrocarbon, and 

nitrous oxide emissions

between 10 and 16 percent. 

The expected average 

annual cost for 

implementing, operating, 

and maintaining all 35 ITS

technologies was about $72 

million. More specifically, 

the expected annual cost for 

implementing, operating, 

and maintaining the regional 

telephone- and Web-based 

traveler information system 

and 5 kiosks was $2.1 

million. 

The expected average 

annual benefit of the ITS to 

mobility, the environment, 

safety, and other areas

($455 million) was greater 

than the expected average 

annual cost to implement, 

operate, and maintain the 

ITS. The benefits

outweighed the costs by a

ratio of 6.3 to 1. 

Nationwide; 2009 Real-Time System 

Management 

Information Program 

Mobility 

Savings in incident delays of 

about 321 million hours, 

annually.

Environment

Reduced annual 

hydrocarbon and nitrous

oxide emissions by about 

8,200 tons and 11,600 tons, 

respectively. Reduced 

annual gasoline use by 

about 447 million gallons. 

The present value of the 

total cost for establishing 

real-time information 

programs in all states and 

the nation’s 50 largest 

metropolitan areas and 

operating these programs

through 2018 would be 

about $1.2 billion. 

The present value of total 

cost savings (about $30.2 

billion) due to benefits to 

mobility, the environment, 

and safety would be greater 

than the present value of the 

costs to establish and 

operate the program. 

Specifically, the present 

value of the benefits would 

exceed the present value of 

the costs by about $29 

billion through 2018. 

Source: GAO analysis of select studies. 

Note: Dollar figures are in current dollars, not adjusted for inflation. The study in Devore, California, 

found that the net benefit of implementing the technologies during 18 days of closures due to 

construction was estimated to be about $3.6 million. However, we could not confirm the reliability of 

this estimate. 

a

This study forecasted the impact of ITS technologies on mobility, the environment, and other areas

in 2025 based on traffic forecasts and planned ITS deployments for that year.

28 GAO-10-121R Real-Time Traffic Information Systems 
29 GAO-10-121R Real-Time Traffic Information Systems 

Enclosure III 

Objectives, Scope, and Methodology

Objectives 

The objectives of this report were 

to determine (1) how state and 

local agencies and the private 

sector disseminate real-time traffic 

information to the public, and the 

completeness of current coverage; 

(2) what actions DOT has taken to 

establish the Real-Time System 

Management Information Program 

required by the Safe, Accountable, 

Flexible, Efficient Transportation 

Equity Act: A Legacy for Users 

(SAFETEA-LU), and stakeholders’ 

views on these actions; and (3) how 

selected experts view the need for 

and benefits of a nationwide realtime traffic information system, 

how they envision such a system, 

and what the related challenges 

may be. We also examined what 

studies have found about the 

impacts of real-time traffic 

information systems and 

technologies—particularly on 

mobility, the environment, and the 

economy—and their costs. 

Scope 

This report focuses on real-time 

traffic information that is 

disseminated to the public. Realtime traffic information that is used 

for traffic management purposes is 

not in the scope of this report. 

Methodology 

• To determine how state and local agencies and the private sector 

disseminate real-time traffic information to the public and the 

completeness of current coverage, we interviewed—and reviewed 

relevant reports and studies obtained from—DOT officials; 

representatives from national organizations involved in real-time 

traffic information initiatives, such as the American Association of 

State Highway and Transportation Officials (AASHTO) and the 

Intelligent Transportation Society of America (ITS America); state and 

local transportation officials; and four private companies involved in 

real-time traffic information initiatives. More specifically, we 

interviewed state and local officials during site visits in California and 

Florida. We selected these locations for site visits because they have 

well-developed real-time traffic information systems, have deployed a 

range of technologies to collect and disseminate real-time traffic 

information, have 511 Traveler Information Services, and have 

differing public-private partnership models for collecting, aggregating, 

and disseminating real-time traffic information. Furthermore, officials 

from DOT, and representatives from AASHTO and ITS America, 

suggested that we visit these locations. The four private companies 

that we interviewed collect, aggregate, and disseminate real-time 

traffic information. To identify these companies, we obtained 

recommendations from DOT, AASHTO, and ITS America as to which 

companies play key roles in those areas. 

We also reviewed and analyzed survey data from DOT’s ITS 

Deployment Tracking Database for 2007, the most recent survey year. 

This database contains state and local agencies’ responses to multiple 

surveys on the deployment of various ITS technologies, including realtime traffic information technologies, in the nation’s 108 largest 

metropolitan areas. The metropolitan areas selected are those that 

have populations of more than 50,000. We focused our review on 

agency responses to two surveys--one on the deployment of ITS 

technologies on freeways and the other on ITS deployments on 

arterial roads. Nearly all metropolitan areas responded to both the 

surveys. We used the survey data in the database to determine the 

types of technologies and systems in use and their coverage. Based on 

interviews with DOT officials and our analysis of the data, we 

determined that the data were sufficiently reliable for the purposes of 

this report, which was to provide (1) general information on the types 

of technologies and systems used to collect and disseminate real-time 

traffic information to the public and (2) general estimates of the 

coverage of these technologies, including the number of metropolitan 

areas in which incident, travel time, and travel speed information 

were disseminated to the public in 2007. 
• To determine what actions DOT has taken to establish the Real-Time 

System Management Information Program, we reviewed and analyzed 

Section 1201 of the 2005 transportation authorization—SAFETEALU—which made DOT responsible for establishing the program. We 

also interviewed DOT officials on their actions to establish the 

program, and reviewed and analyzed the proposed rule and related 

guidance that DOT published in the Federal Register. To determine 

stakeholders’ views on the expected benefits and challenges to 

implementing the proposed program, we interviewed selected state 

and local transportation officials and representatives of AASHTO and 

two private companies that provide real-time traffic data. The state 

and local officials we interviewed on this issue were those that we 

met with during our site visits and those selected by the National 

Academy of Sciences (NAS). Later in this section we provide further 

details on how NAS selected state and local government officials and 

other stakeholders. The private companies we interviewed were 

those identified as key data providers by our own work and NAS. To 

further identify expected benefits of, and challenges to implementing 

the program, we reviewed and analyzed comments that state and local 

agencies, private companies, and organizations submitted to DOT in 

response to the proposed rule and related guidance that DOT 

published in the Federal Register. 

• To determine experts’ views on a nationwide system, we conducted 

semistructured interviews with—and reviewed relevant 

documentation from—19 experts about options for implementing a 

nationwide real-time traffic information system, including the need 

for, potential benefits of, and challenges to implementing such a 

system.24 The individuals we interviewed from state and local 

transportation agencies, academia, and the private sector (consultants 

and data providers) were selected by NAS. NAS selected these 

experts based on geographic diversity and their knowledge of various 

aspects of real-time traffic information systems and technologies, 

including the roles of the federal, state, and local governments and the 

private sector; key technologies used in collecting, aggregating, and 

disseminating traffic information to the public; various models for 

providing traffic information services; and current efforts to 

implement a nationwide real-time traffic information system. We 

identified three officials from DOT as experts because these 

individuals work on issues, policies, and regulations related to realtime traveler or traffic information and were identified by DOT as 

points of contact in these areas. The 19 experts we interviewed and 

their affiliations are listed in table 6. 

 

24We did not evaluate the experts' options for a nationwide system, including 

factors such as the feasibility and implementation costs associated with these 

options. 

30 GAO-10-121R Real-Time Traffic Information Systems 
31 GAO-10-121R Real-Time Traffic Information Systems 

Methodology (continued) 

Table 6: Names of Experts We Interviewed and Their Affiliations 

DOT 

State level 

associations 

State 

Departments 

of 

Transportation

Local 

transportation 

agencies Academia 

Private industry 

(consultants) 

Private 

industry 

(data 

providers) 

Jane Lappin 

Volpe National 

Transportation 

Systems Center 

George Schoener 

I-95 Corridor 

Coalition 

Anthony 

Bradford

Georgia

Department of 

Transportation 

Matt Edelman 

Transportation 

Operations

Coordinating 

Committee 

(TRANSCOM) 

Mark Hallenbeck 

Washington State 

Transportation 

Center 

Dean Deeter 

Athey Creek 

Consultants

John Collins 

Transportation 

Business Law 

and Strategy 

(formerly with 

NAVTEQ 

Traffic) 

James Pol 

ITS Joint Program 

Office 

James Wright 

American 

Association of 

State Highway and 

Transportation 

Officials

(AASHTO) 

David Huft 

South Dakota

Department of 

Transportation 

David Fink 

Houston TransStar

Christopher Poe 

Texas

Transportation 

Institute 

Les Jacobson 

Telvent 

Farradyne Inc. 

Rick Shuman 

INRIX 

Robert Rupert 

Federal Highway 

Administration 

Greg Krueger 

Michigan 

Department of 

Transportation 

Carol Kuester 

Metropolitan 

Transportation 

Commission 

Philip J. Tarnoff 

University of 

Maryland 

David Lively 

California

Department of 

Transportation 

Source: GAO.
32 GAO-10-121R Real-Time Traffic Information Systems 

Other Aspects of Our Work 

• To describe what studies have found about the impacts (on mobility, 

the environment, and the economy) and costs of real-time traffic 

information technologies and systems, we conducted a literature 

review to identify pertinent studies. Specifically, we targeted our 

literature search to the Transportation Research Information Services 

database—a bibliographic database on transportation issues—and 

DOT’s ITS Benefits and Costs databases. Our search of these 

databases did not yield studies on the impacts of real-time traffic 

information systems and technologies on the economy. Therefore, we 

extended our literature search to additional databases, including the 

EconLit bibliographic database—a database in the field of 

economics—and the ProQuest and WorldCat databases. Our 

literature search covered studies published from 2004 onward. 

Through the literature search, we identified a number of studies that 

discussed technologies and systems that disseminate, or support the 

dissemination of, real-time traffic information to the public. We 

further limited our review to studies that evaluated real-time traffic 

information technologies and systems in the United States and that (1) 

quantified the impacts of real-time traffic information technologies 

and systems on mobility, the environment, or the economy; (2) 

identified the costs of these systems or technologies; or (3) conducted 

benefit-cost analyses. Based on these criteria, we identified a total of 

20 studies that were relevant and applicable to our report. We 

reviewed the methodologies of these studies to ensure that they were 

sound and determined that they were sufficiently reliable for 

describing the impacts and costs of real-time traffic information 

systems and technologies.25

We conducted this performance audit from January 2009 to November 

2009, in accordance with generally accepted government auditing 

standards. Those standards require that we plan and perform the audit to 

obtain sufficient, appropriate evidence to provide a reasonable basis for 

our findings and conclusions based on our audit objectives. We believe 

the evidence obtained provides a reasonable basis for our findings and 

conclusions based on our audit objectives. 

 

25Dollar figures used to describe the costs or cost savings of real-time traffic 

information systems and technologies are in current dollars, not adjusted for 

inflation. 
Enclosure IV 

GAO Contact and Staff Acknowledgments

GAO Contact 

David J. Wise, (202) 512–2834, or wised@gao.gov

Staff Acknowledgments 

In addition to the contact named above, Judy Guilliams-Tapia, Assistant 

Director; Lauren Akers; Dwayne Curry; Roshni Davé; Bess Eisenstadt; 

Kathleen Gilhooly; Brandon Haller; Terence Lam; Kirsten Lauber; Ashley 

McCall; Josh Ormond; Madhav Panwar; and Gretchen Snoey made key 

contributions to this report. 

(542151) 

33 GAO-10-121R Real-Time Traffic Information Systems 
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