**SAFETEA-LU, Sect. 1201, Real-Time System Management Information
Program - Request for Comments on Interim Guidance (FHWA-2007-28969)**

**Interim CARS Pooled Fund Response**

## Introduction

U.S. state and Canadian agencies have jointly developed Advanced Traffic
Management Systems (ATMS) and Advanced Traveler Information Systems
(ATIS) software (Condition Acquisition and Reporting System---CARS)
based wholly on USDOT--sponsored standards. The Pooled Fund has expanded
swiftly in recent years, and now includes over twenty agencies spread
throughout the United States and Canada.

CARS Pooled Fund member agencies have already realized many of the goals
set out in section 1201 of SAFETEA-LU. Since its inception in 1998, CARS
has been based around ***TMDD*** national ITS standards--based direct
data feed components that publish event data for other states, software
applications, and data-sharing partners to utilize (initially using the
TMDD Event Report Message---ERM). The CARS software suite has since been
enhanced to support other standards: the "expedited" Full Event Update
message (FEU), DMS control message, CCTV control message, and traffic
detector message (all TMDD standards-based); and IEEE 1512 incident
messages for communications with Police CAD systems.

Because CARS Pooled Fund agencies have already established a successful
working model for the exchange of real-time travel information, we
believe it is extremely important that this substantial investment and
its corresponding hands-on, practical experience be preserved and
safeguarded. The forthcoming SAFETEA-LU mandate to establish a Real-Time
System Management Information Program for U.S. states should reflect
that fact that nearly 50% of U.S. state agencies already have fully
interoperable working ATMS/ATIS systems based on existing TMDD data
standards.

However, we believe that the FHWA-2007-28969 interim guidelines do not
reflect the widespread successful implementation of these TMDD-based
standards. The guidelines, as currently drafted, do not reflect the
decade of successful deployment and millions of dollars of investments
by the states. The remainder of this response outlines why the current
recommendations should be amended to reflect these current realities. We
have aimed specifically to illustrate how currently operational systems
use already use appropriate TMDD standards to meet the identified RTIP
requirements specification.

It is worth repeating that this is not a theoretical proposal, but that
TMDD standards are already widely deployed and used operationally on a
day-to-day basis in mission-critical ATIS and ATMS systems throughout
the United States and Canada. A mandate which significantly differed
from existing operational practice (as reflected in the current interim
guidelines draft) would result in an unacceptable burden on agencies who
could have to make major changes to existing systems to meet the new
mandate. Most importantly, a decade of practical lessons learned would
have been thrown away, replacing operationally proven standards with
committee proposals from groups that include little state DOT
representation.

The CARS Pooled Fund response to FHWA-2007-28969 covers three primary
topics:

-   General Response

-   Response to Solicited Feedback

-   Recommended Revisions to the RTIP Standards Reference

## General Response 

Since its inception, the CARS software has enabled adjacent states to
share event data via an Event Report Message (ERM) interface. The Trio
states of Maine, New Hampshire and Vermont have utilized this feature
since 2001, allowing each of them to display the events of the other two
states on their public web pages. Kentucky has successfully used the
TMDD event report message (ERM) to import crash and congestion reports
from Cincinnati's ARTIMIS. Maine has used the TMDD ERM to support ATIS
outputs to its visually and hearing-impaired citizens. Alaska has used
the standard for ferry information systems integration and Road-Weather
Station (RWIS) integration with its statewide CARS deployment. All
twelve CARS-511 states use it as the core system that drives their
statewide 511 deployments. Seventeen state and provincial agencies
currently use ERM to drive statewide ATIS 511 web sites. These pre-TMDD
version 2.1 ERM applications represent a total investment in excess of
\$8 million.

Since February 2004, CARS agencies have also been actively developing
and deploying center-to-center data exchanges based on TMDD version 2.
The Idaho Transportation Department is currently implementing a two-way
data exchange with the IBI Group's Ada County ATMS/ATIS using TMDD's FEU
(Full Event Update) message. New Hampshire DOT is integrating its Delcan
ATMS with its statewide CARS and 511 systems using FEU. Iowa Department
of Transportation (IADOT) is moving ahead with data exchanges that will
bring Eastern Iowa (and later other regional sub-centers') data into the
statewide CARS system. Maine is integrating its statewide CARS and
maintenance management system MATS to support posted road traffic events
(weight limits during the spring seasonal thaw). Alaska uses FEU to
export statewide traffic, construction, road weather and special event
data to a statewide data warehouse. Five states (IA, ID, ME, NH, VT) are
already using FEU to drive "Next-Generation" Google Maps based ATIS.
Eight more states plan to follow this lead in 2008. Another eight states
will launch Next-Gen 511 systems based on TMDD FEU in 2008. All of these
deployments include traffic events, road condition reports, and
incidents/crashes. Maine's will also use FEU to help support a live data
feed from Amtrak, having previously used TMDD's ERM to convey real-time
bus schedule adherence to the public in the Federally funded Acadia
National Park project (live since 2004).

Although the draft guidelines would allow the use of "TMDD" for "traffic
events", large numbers of actual traffic/travel event types are also
listed in the proposed requirements with no mention of a TMDD-based
standards approach. In the CARS states' view, the current draft does not
reflect what is actually meant by the term "traffic/travel events",
which include crashes, incidents, delays, road condition reports,
adverse driving (weather) reports, and transit delays/cancellations,
among many others.

When CARS was first launched, its event data exchanges were supported by
the Datex protocol, using socket connections. In 2000, CARS switched to
XML in support of all its data sharing functions. State-to-state event
report exchanges take place using the TMDD ERM message over XML Direct,
in accordance with NTCIP 2306. XML message exchanges now supported in
CARS also include Comcare Alliance Mayday messages from OnStar and IEEE
P1512 messages from police CAD systems, in addition to TMDD messages.

Also, as a result of the ongoing ITS standards process, the ERM has been
superseded by the TMDD Full Event Update (FEU) message. For these
reasons, ERM is now being phased out of use in CARS. At considerable
effort and expense to the agencies involved, all CARS systems will use
the current TMDD FEU message instead of ERM. Messages will be exchanged
using XML direct, SOAP push, and indexed XML, allowing data exchange
latencies to be greatly reduced.

The CARS group strongly believes that the most appropriate ITS standard
be used for a given type of data exchange. CARS members have used TMDD,
IEEE P1512 and SAE J2354 where appropriate. However, CARS members have
elected to use TMDD for the vast majority of data exchange messages, as
it is most appropriate to traffic management and road condition
activities. TMDD event reporting messages offer the ideal means of
exchanging event information affecting the road network, which can be
effectively translated into traveler information messages at the
dissemination point(s).

The CARS group believes that the current FHWA-2007-28969 interim
guidelines (and impending mandate) do not adequately reflect these
existing operational practices. Specifically:

1.  The recommended mapping of RTIP specifications to ITS standards
    needs to be substantially expanded, both theoretically and to
    reflect current operational practices.

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1.  The Functional Specifications need to be enhanced in some
    significant areas (including, but not limited to, transit events and
    schedule adherence areas).

Over the next week, the CARS states will submit a further appraisal of
the current draft guidelines with detailed suggestions for enhancements
and amendments.