Chapter 13 – Information
Page 3 of 3
13.2.11 Emerging Trends
As previously discussed, "511" telephone-based traveler information is
still emerging as a trend through the Nation. Each implementation brings
with it new lessons and different approaches.
188.8.131.52 Amber Alerts
Another trend in traveler information relates to the use of traveler
information devices to inform motorists of abducted children. The Amber
Alert Plan Program is a voluntary program where law enforcement agencies
partner with broadcasters to issue an urgent bulletin in the most serious
child abduction cases. These bulletins notify the public about abductions
of children. The USDOT recognizes the value of the Amber Plan Program
and fully supports the State and local governments' choice to implement
this program. (13)
Alerts of recent serious child abductions may be communicated through
various means including radio and television stations, HAR, CMS, and other
media. Under certain circumstances, using VMS to display child abduction
messages as part of an Amber Plan Program has been determined to be consistent
with current FHWA policy governing the use of VMS and the type of messages
that are displayed. The FHWA, in fact, recently issued a policy memorandum
that supports the use of CMS for Amber Alerts. This memorandum may be
viewed at the following URL: http://ops.fhwa.dot.gov/Travel/reports/amber.htm.
A key factor in the success of the Amber Plan Program is the need for
public agencies to develop formal Amber Plan policies that include a sound
set of procedures for calling an Amber Alert. If public agencies decide
to display an Amber Alert or child abduction messages on a CMS, the FHWA
has determined that this application is acceptable only if it is part
of a well-established local Amber Plan Program, and public agencies have
developed a formal policy that governs the operation and messages that
are displayed on CMS. Care must be exercised to ensure that the message
displayed does not exceed the reading and information processing capabilities
of the motorists.
184.108.40.206 Integrated Network of Transportation Information (INTI)
A recent initiative, primarily driven by ITS America, is the "Integrated
Network of Transportation Information" (INTI). The creation of an INTI
is one of the programmatic themes contained in the "National ITS Program
Plan: A Ten-Year Vision" (14).
As stated in that document, an Integrated Network of Transportation Information
- "Create, operate, maintain and update the information management mechanisms
to gather, analyze, coordinate, extrapolate, and store the data and
interact with adjoining external systems. This will necessarily be done
at multiple levels by a large number of organizations under consistent
guidelines for information gathering, validating, sharing, and coordinating."
- "Implement appropriate policies, procedures and security technologies
to ensure that the system is secure and that only authorized stakeholders
have access to data."
The INTI was the subject of a workshop entitled "INTI – Moving Toward
and Integrated Network of Transportation Information: From Information
to Integration", held in Houston, TX in February 2003. The INTI was presented
at this workshop as consisting of three building blocks – gathering
data, sharing data, and using data.
Also presented were several key attributes and issues, including:
- Implementation should not be heavily infrastructure-based; rather,
the long-term path is heavily vehicle-based (but not exclusively) both
on collection and delivery side. Travel time is key; weather information
is also important. Program will not be Federally mandated (in whole)
or controlled; although there may be Federal incentives and, likely,
a Federal coordination role.
- Both public and private innovation, commitment, and contribution will
be required. It cannot be just a public or private sector initiative.
13.3 Implementation and Operational Considerations
13.3.1 CMS Messages
CMSs are one of the primary links a transportation agency has to the
motoring public it serves. Improperly designed or operated CMS messages
(e.g., displaying messages that are too long for motorists to read at
prevailing highway speeds, or that are too complex or inappropriately
designed leading to motorist confusion) can adversely affect both traffic
flow and the transportation agency's credibility. The design and display
of messages on CMSs introduce many challenges to transportation agencies
and freeway practitioners. Recommendations to meet these challenges are
presented in the Guidelines for Changeable Message Sign Messages
Manual (Reference 5),
which is a consolidation of the most current and best information on the
design and display of effective CMS messages for incident and roadwork
Some of the more relevant issues identified in the Guidelines are briefly
- Efforts must be made to ensure that CMS messages are standardized
and consistently applied throughout a state or region—The
messages displayed must be "transparent" to travelers in the state or
region. Therefore, messages need to be presented in a consistent manner
and order based on motorists' expectancies.
- Steps can be taken when developing CMS messages to enhance
motorist understanding of messages—In developing messages,
factors that enhance understanding of messages include the following:
- Simplicity of words,
- Standardized order of words,
- Standardized order of message informational units,
- Understood abbreviations when abbreviations are needed, and
- Standardized applications of messages.
An efficient, brief, and to-the-point message is a good message. Just
because there are spaces available on a CMS does not mean that all spaces
should be used for a message.
- CMS messages should be displayed and changed in a timely
manner—The importance of timely display of CMS messages
stems back to credibility. CMS operators do not always have all the
information necessary to display messages that provide all of the details
for motorists to make decisions. This is particularly true immediately
after the operators are notified that an incident has occurred. Information
should be displayed as quickly as it becomes available, recognizing
that the CMS operator may have to change a message several times over
the course of the event as new information becomes available or traffic
- Operating agencies should have written CMS policies and/or
operational procedures—CMS message design and display
should be predicated on CMS operational policies and procedures. Although
an agency is more likely to have written operational procedures, most
do not have written policies. Operational policies dictate some of the
requirements for operational procedures.
- CMS message objectives should be established and messages
should be designed before CMSs are purchased—Too often,
agencies purchase CMSs before signing objectives and messages are determined.
The consequence is disappointment in the inability of the CMS system
to display the appropriate messages because the sign does not have enough
lines, and/or the line length is not long enough to display the desired
messages. In addition, the CMSs have lower than expected target value
and legibility for the environmental conditions present at the site.
A recommended procedure for determining the types of CMSs that will be
acceptable for a given application is provided as summarized below. It
should be noted that the nine steps of the procedure are interrelated
and that the procedure is an iterative process.
- Clearly establish the objectives of the CMS – The importance of setting
signing objectives cannot be overemphasized because the objectives directly
influence message content, format, length, and redundancy, and consequently,
the size and placement of the CMS. When setting objectives, the agency
must be specific in defining: What the problem is that
is to be addressed with the CMS; Who is to be communicated
with (audience); What type of driver response is desired;
Where the change should take place; What
degree of driver response is required; and How the
CMS system will be operated.
- Prepare the messages necessary to accomplish the objectives – The
length of the messages will help define the character size, message
line length, and number of message lines required on the CMS. It may
be necessary to modify some of the messages to reduce their lengths
as a result of conditions determined in subsequent steps.
- Determine legibility distance required to allow motorists ample time
to read and comprehend the messages.
- Determine locations of the CMS that allows motorists ample distance
to read, comprehend and react to the messages – The CMS must be placed
such that the CMS and existing static signs form an integrated and compatible
system of information.
- Identify type and extent of localized constraints that might affect
the legibility of the CMS – Field inspections are advisable to ensure
that there are no physical obstructions due to bridges, sign structures,
geometries, etc. that would adversely affect CMS legibility. In addition,
field inspections will also help determine whether or not it is possible
to actually install a CMS at the site. Obstruction problems would require
that the agency either relocate the CMS or reduce the length of the
- Identify the environmental conditions under which the CMS will operate
– Weather conditions such as snow, rain, etc. and other conditions
such as blowing dust, heat, cold, etc. will have an effect on the sign's
operation and will, in most cases affect the legibility of the messages.
These environmental conditions should be made known to the manufacturer
so that the best CMS performance characteristics can be achieved.
- Determine the target value and legibility of candidate CMSs – An
evaluation of the capabilities of the CMSs may dictate the need to reduce
the message length or to require the manufacturer to modify the hardware
and/or electronics to improve legibility.
- Determine the costs of candidate CMSs.
- Select the CMS that will allow the selected messages to be read under
all environmental conditions within the cost constraints of the agency.
220.127.116.11 CMS Credibility
Paramount to the message design and display, CMSs must provide timely,
reliable, accurate and relevant information and they must be operated
properly to be effective. Credibility is an extremely important consideration
in properly operating a CMS system. Regardless of how well a message is
designed, motorists will eventually come to distrust the signing system
if the messages are not changed at the correct times and updated to reflect
current traffic conditions. Each time the information displayed is disproved,
the credibility of the system decreases. Eventually the messages are ignored
and the CMS system is in jeopardy. There are at least eight reasons why
message credibility suffers (5):
- Information is inaccurate (e.g., no crash is observed
when traffic passes by the location where an incident was displayed
on a CMS).
- Information is not current (e.g., the message is
not consistent with current conditions).
- Information is irrelevant to essentially all motorists
using that facility.
- Information is obvious by inspection, and hence,
is redundant (e.g., displaying Heavy Congestion when motorists are driving
bumper to bumper in peak traffic).
- Information is repetitive (the message is the same
each morning when motorists pass the sign). Displaying the same information
on a CMS each day for recurrent congestion can result in many motorists
ignoring the CMS after a time. When an important message is displayed
that will impact their trip, the motorists may not read the message.
Some agencies are even considering the use of flashing beacons on CMSs
to attract the attention of motorists when important messages are displayed.
- Information is trivial (e.g., Drive Carefully, Support
Your Local Red Cross, time and temperature). Displaying trivial information
can result in many motorists, particularly commuters, ignoring the messages
that have no direct impact on their trips and consequently will begin
ignoring the CMS. When an important message is displayed that will impact
their trip, the motorists may not read the message.
- Information is erroneous and can be easily checked
and disproved. Traffic speeds and time to reach a destination are examples
of information that can be easily disproved. Delay time is more difficult
to disprove by motorists.
- Messages are poorly designed. The information is
poorly structured resulting in messages that are difficult to read and
comprehend, or are confusing. The messages may also contain misspelled
18.104.22.168 CMS Usage
Once a CMS system is installed, a question always arises concerning when
messages should be displayed. There are two schools of thought:
- Display messages only when unusual conditions exist on the freeway;
- Always display some sort of message regardless of whether or not unusual
conditions exist on the freeway.
The Manual (5)
subscribes to the former of the two approaches because of human factors
principles and because of difficulties in designing messages when incidents
actually occur during the peak periods. The second approach of always
displaying a message leads to violation of the following two important
human factors principles – specifically, don't tell drivers something
they already know; and use the CMSs only when some response by drivers
is required (i.e., change in speed, path, or route).
The Arizona DOT Guidelines (7)
indicate, "CMS should be used whenever pertinent messages will assist
motorists to make helpful decisions. If, however, a situation arises,
which requires the usage of a specific CMS for more than one ongoing condition;
the following priority criteria should be used for displaying messages,
in the order listed.
- Roadway Closure
- Minor Traffic Impact
- Pre-Warning (e.g., construction lane closures, blocking-incidents,
and delay information.
- Public Service Information"
13.3.2 HAR Operations
While HAR is a viable traveler information system, its effectiveness
is limited only by its operational application. How the messages are distributed
and the equipment that distributes it is very important to a successful
The HAR can use either live messages, pre-selected taped messages, or
synthesized messages based on information from an ITS traveler information
database. The following issues are important in the design and implementation
of an effective HAR system.
The audio quality, content, structure, presentation, and length of the
advisory message are important parameters in providing an effective
messaging system. Sound quality is affected by a number of different
items: quality and sensitivity of the automobile receiver; quality of
the transmission or control lines used to load the message; quality
of the original recording when loaded to the transmitter controller
or system controller; characteristics of the voice used to record the
message; quality of the transmission and recording equipment; and the
quality of the transmitter, antenna, and ground plane system. The only
definitive way to ensure the quality of the transmission signal, and
clarity and audibility of advisory messages, is by off-the-air monitoring.
This type of monitoring involves receiving and monitoring the broadcast
messages, using an AM radio receiver, in the same manner that a motorist
would receive the messages. A routine monitoring program should be established
that ensures all transmitters in the system are monitored off-the-air
on a regular basis. Case-by-case and periodic monitoring of advisory
messages should also be undertaken to ensure acceptable audio quality.
The message must be clear, concise, relevant, and easy for the motorist
to understand. Because a motorist may begin hearing the advisory message
at any point in the message, the message should consist of a sequence
of independent phrases, so that the listener will not be confused by lack
of information in the previous portion of the message. Slow, deliberate
speech will provide greater comprehension of messages with detailed content.
With traffic advisory messages, the motorists must receive the information
before encountering the congested area.
Ideally, motorists should only receive messages relevant to the geographic
area they are in or are about to enter; this mandates the need to separate
broadcast areas. However, because radio wave propagation differs greatly
depending on topography, atmospheric conditions and time-of-day, the potential
for interference in overlapping radio coverage areas that use the same
transmitting frequency can be significant. Overall systems design and
final selection of transmission technologies need to account for these
13.3.3 ATIS Business Planning
Agencies that are considering expanding their ATIS business beyond roadway
devices to encompass web sites, partnerships with the private sector (ISP's),
etc., need to address several issues – for example, what information will
be distributed, to whom, how, potential revenue generation, restrictions,
etc. Some of these issues are discussed below.
22.214.171.124 Business Models
A variety of ATIS business models have been used in the U.S., with varied
successes. At present, it is safe to say that no one model have proven
reliably profitable. Much the same can be said for ATIS in other parts
of the world, too. The ATLANTIC (A Thematic Long-term Approach to Networking
for the Telematics and ITS Community) Project's ATIS subtask undertook
a study of comparing current practices of ATIS, including business models,
that have been tried in recent years in countries on both sides of the
Atlantic Ocean – the three communities of ITS experts in Europe, Canada,
and US. The significant results as well as the methodology for the comparative
analysis are summarized below: (15)
- Both Europe and North America need to have a complete information
value chain for delivery of ATIS services. The information
value chain (or information supply chain) for ATIS describes a complete
system from data collection, data fusion, to data distribution. All
the links in the system must be operative for ATIS service delivery.
Service quality to end-users is only as good as the weakest link in
the information supply chain.
- Broadcast traveler information supported by advertisement
has been proven to be viable. In fact, the broadcast of traffic
information supported by advertisement has proven to be viable for years.
It is a very viable revenue producing method. Perhaps the next question
should be about market development, not about viable advertising revenue.
In the US, the Metro Networks model of selling airtime to advertisers
during radio traffic reports has been a success. However, given the
conglomeration of services that has occurred over the past few years
(i.e., Westwood One incorporating Shadow, Metro Networks, and Smart
Routes), it could be questioned how viable the competitive broadcast
market really is. It should be noted that ATIS is beyond traffic broadcast.
ATIS will require a quantum change in data gathering methods, from qualitative
"reportage" to quantified data-rich sources. Other models,
such as advertising on websites, have not been very successful or profitable.
For example, advertising on the SmarTraveler cable TV service was not
successful in the US.
- Public sector agencies should be prepared to underwrite all
costs of specific information services they wish to provide.
This is certainly true for information services free at the point of
use and offered as a public service, such as Traveler Advisory Telephone
Systems, Government Access Channel Traffic TV Systems, and Government
Websites. It is also true for some public transportation information
systems but not necessarily true for commercial, personalized subscription
services and for wireless services to mobile and portable devices. There
may be certain services (e.g., subscription-based services) that the
public sector would offer only if partnered with another
firm that would assume fiscal responsibility for the service. These
types of services may be akin to "bells and whistles" in that
they would not be deemed essential public services, but could still
be very effective in meeting public policy goals. Thus, there may be
some services that the private sector can provide, especially for niche
markets such as commercial vehicles or business travelers. The public
sector would have an interest in seeing these markets served but public
support may not be required. In this case, public sector agencies might
consider underwriting the costs of providing the framework necessary
to enable those services to be provided, or proceed in partnership with
the private sector.
126.96.36.199 Public-Private Partnering
Some differences in philosophies between the public and private sectors
must be realized, understood, and overcome. Typically the public sector,
or the provider of the data, desires to disseminate the information to
the widest possible audience, while the private sector's primary goal
is profit-oriented, and the two philosophies must be synergized to realize
the ultimate goal of each group. A January 2002 study for FHWA on the
subject of sharing public data identified the following findings: (16)
- Agencies have two major objectives in sharing their data with private
sector and other public sector recipients: improving transportation
operations through better interagency coordination and optimizing the
use of the transportation system by providing information to travelers.
Enhancing interagency coordination was the top-ranked motive for data
- Even though their motives are different, public and private sectors
are active participants in use of traveler information as a transportation
management tool. Almost all agencies directly provide information to
the public typically with VMS, HAR, kiosks, and interactive voice response
telephones. Although agency data are a fundamental source, private providers
generally need to enhance public data before they are marketable. The
most common types of information provided are traffic and road conditions,
incident information, and planned construction information. Transit
data are generally less useful to private providers, and only a third
of them report transit delay information.
- Agencies that have data to share protect their interests by placing
restrictions on access to data, but firms generally do not find these
conditions to be onerous. Two or more conditions on access are common,
the most frequent being acknowledgement of the agency as the source
of the data when distributed to the public.
- Formal policies on data sharing were reported by half the 34 surveyed
agencies and several more have plans to issue one. The principal advantage
of a formal policy is that it provides a process for handling requests
for agency data.
- In addressing the costs associated with the data sharing process,
agencies frequently employ two or more cost recovery mechanisms in data
sharing relationships. Most frequently agencies require the receiving
party to cover its own cost, such as hardware, software and communications
cost to connect to agency data sources. The second most popular mechanism
involves a private firm sharing its "value-added" information
with the agency.
- The two most controversial topics in the private sector's relationships
with agencies regarding agency data are revenue sharing and exclusivity.
The idea of revenue sharing is optimistically viewed by many agencies,
although in practice it has not had much success. The private sector
tends to oppose revenue sharing either because of practical difficulties
in administering it or because it violates the principle that public
data should be available to all taxpayers for free.
There can be little doubt, then, that the private sector must be a full-fledged
partner in deploying and managing traveler information dissemination systems
(e.g., the INTI). Moreover, private sector participation will likely go
beyond using, value-adding, and delivering public data; and also include
the generation and collection of information. While this approach is appealing
(and probably necessary), past experience has shown that it is not always
an easy process. As noted above, there are several issues that must be
addressed if effective partnerships are to be established for the collection
of information, including:
- Data ownership – When a private entity is involved in the collection
of traffic flow information, it is important to establish ownership
early in the process, so that the rights of each party to use, distribute,
and/or sell the data are defined.
- Exclusivity – Many public agencies are legally required to disseminate
any data collected with public funds to all requesting organizations.
An agency may therefore be prevented from giving exclusive rights to
a private sector organization with which it has entered into a "surveillance"
partnership, forcing the private sector partner to compete with other
entities that have not made a similar investment.
13.4.1 511 Virginia
511 Virginia is a Virginia Department of Transportation (VDOT)
service, contracted to Virginia Tech Transportation Institute (VTTI),
who in turn has subcontracts and service contracts with additional parties,
including Shenandoah Telecommunications (Shentel) and Tellme Networks,
The 511 Virginia service grew out of the Travel Shenandoah regional
travel information service that was launched in July 2000, serving the
primarily rural part of western Virginia. Situated along 150 miles of
the Interstate 81 corridor, Travel Shenandoah covered 11 counties and
one VDOT District – Staunton.
Before launching the 511 Virginia service, the coverage area
was expanded to include the entire length of I-81 in Virginia and all
major roadways in three VDOT Districts – Staunton, Salem and Bristol. Today, 511 Virginia serves 35 counties and a resident population of approximately 1.4 million
people. Virginia was the first to offer services beyond traditional transportation-related
information including information on food and lodging, tourism and attractions,
and shopping. The information is provided via an interactive voice actuated
system (no need to press buttons) via the 511 dialing code and also through
a companion website, www.511Virginia.org.
In support of the service, VDOT has placed 58 roadside signs along I-81
and the intersecting Interstate approaches in the region to help promote
the service. VDOT has also produced public service announcements, rack
cards, and other promotional materials. The exact level of marketing to
attract and maintain a high-volume, consistent user base is currently
unknown. However, consistent marketing and brand awareness are critical
to the success of 511 Virginia and 511 services nationwide. Therefore,
all marketing materials produced will use the 511 Deployment Coalition
developed and distributed 511 logo and usage guidelines.
The AZTech™ Intelligent ™Transportation System (ITS) Model Deployment
Initiative (MDI) is a seven-year project (two-year implementation and
five-year operation) to develop an integrated Intelligent Transportation
System for the Phoenix metropolitan area. AZTech™ is a unique transportation
partnership of public agencies and private corporations who integrate
travel and communication systems within the Phoenix metropolitan area.
This partnership provides Arizona motorists with traveler information
such as real-time traffic conditions, related road closures, and accidents.
This information is provided through the use of live traffic cameras,
variable message signs and through a large network of fiber optics and
communications systems. In addition to the ATIS element, other major components
of AZTech™ include regional operations partnership, smart corridors,
incident management, system integration, emergency management, data archiving,
special event management, regional procurement, and telecommunications
AZTech™ has been successful in building a unique ATIS public-private
business model. The Advanced Traveler Information System business model
provides the structure for Maricopa County's regional transportation partnership.
Bridging the gap between public and private businesses, this partnership
enables the private sector to operate a self-sustaining automated traveler
information system encompassing state-of-the-art technology.
AZTech™ has finished both Phase 1 and Phase II public-private partnership
projects as follows:
- Phase I of the AZTech™ project involved utilizing prominent
internet portals, such as MSN and MapQuest, to disseminate information.
Personalized traveler information was also provided to commuters utilizing
devices such as PDA's and in-vehicle services through GM Onstar.
- Phase II of the AZTech™ project involved increasing its Internet
capabilities, as well as setting up notifications to be distributed
by fax and through digital TV. Additionally, through one of its partners,
AZTech™'s was able to set up real-time traveler information, including
travel time, for commercial vehicle operations. Another AZTech™
partner provided traveler information on in-vehicle devices.
The business model allows AZTech™ to participate in the fusion
of better traffic data. Both private firms and public companies add value
to data collected by and disseminated from AZTech, resulting in better
information for all travelers. Proof that this business model has tangible
benefits can be found in AZTech™'s involvement in researching and
testing the latest technical achievements. Recently, AZTech™ performed
a production test of a new personalized traffic service. Using wireless
capabilities, real-time travel information was disseminated to users throughout
the Phoenix metropolitan area. AZTech™ partners created personal
trip profiles on the ATIS private partner service. Alerts were available
for dissemination to cellular phone, WAP phone, PDA, pager, fax and email.
The user then customized information by entering details such as:
- Personalized freeway route;
- Times of day to activate notification; and
- Level of severity of activated alert.
The user specified the preferred device that was to receive traffic alerts.
Any activity reported on a specific route, including incidents, recurring
and non-recurring congestion, and construction, was then automatically
distributed to the user's specified device.
Another successful outcome of the public-private partnership initiated
by AZTech™ has been the introduction of a dedicated traffic cable
channel in four jurisdictions. The cable television channels provide information
regarding travel conditions through data fusion from the freeway management
system at peak travel hours.
With the launch of Phase III, AZTech™ has entered a new era of
travel information services. New services include travel time prediction,
dissemination, and enhanced Internet services. Additional information
can be found on the AZTech™ website at www.aztech.org.
1. Keever, D. et al; "Data Fusion for Delivering Advanced
Traveler Information System (ATIS) Services"; Working Draft; SAIC; November
2. Dudek, C.L. Guidelines on the Use of Changeable
Message Signs. Report No. FHWATS-90-043. FHWA, U.S. Department of Transportation,
Washington, DC, May 1991.
3. Wunderlich, K. et al; "On-Time Reliability Impacts
of Advanced Traveler Information Services (ATIS): Washington, DC Case
Study"; FHWA; January 2001,
4. Dudek, C.L. and Huchingson, R.D. Manual on Real-Time
Motorist Information Displays. Report No. FHWA-IP-86-016. FHWA, U.S. Department
of Transportation, Washington, DC, August 1986.
5. Dudek, Conrad L., "Guidelines for Changeable Message
Sign Messages", Report No. FHWA-OP-03-070. FHWA, Department of Transportation,
Washington, DC, December 2002.
6. Dudek, C.L. Changeable Message Signs. NCHRP Synthesis
of Highway Practice No. 61. TRB, National Research Council, Washington,
7. Arizona Department of Transportation / Transportation
Technology Group; "Guidelines on the Use of Permanent Variable Message
Signs"; March 2002
8. ITS Standards advisory; Dynamic Message Signs (DMS);
January 2003 Advisory No. 1
9. Specification Guide for Procurement of NTCIP-compliant
Dynamic Message Signs (DMS); FHWA Joint Program Office; October 2002
10. Schuman, R. and Sherer, E. "511" "101";, 511
Deployment Conference, Scottsdale, Arizona, March 2002.
11. "Resource 511" website, http://www.deploy511.org
12. 511 Deployment Coalition, "511 America's Travel
Information Number, Implementation Guidelines for Launching 511 Services",
version 1.1, June 2002.
13. FHWA website, http://www.ops.fhwa.dot.gov/Travel/ambersol.htm
14. ITS National Program Plan; ITS America
15. Chen, K. ATIS Practices in Europe and North America
– A Report on Comparative Analysis. Contract No. DTFH61-96-C-00077. USDOT,
Washington, DC, October 2002.
16. Zimmerman, C., Mallett, W., Raman, M., and Roberts,
C. Sharing Data for Traveler Information: Practices and Policies of Public
Agencies. Contract No. DTFH61-96-C-00077. USDOT, Washington, DC, January
17. 511 Deployment Coalition, "511 Brochure"
18. Schuman, R. and Sherer, A. ATIS U.S. Business
Models Review. USDOT, Washington, DC, November 2001.
19. The ITS National Architecture, Documentation
– Version 4.0, April 2002
20. AZTech web site, www.aztec.org
21. "Manual on Uniform Traffic Control Devices" (MUTCD)
2000, Millenium Edition, Institute of Transportation Engineers, Washington,