The Virginia Department of Transportation (VDOT) has made a
substantial investment in development of the Northern Virginia Smart Traffic
Center (NoVa STC). Located in Arlington, Va., the NoVa STC has been in
successful operation for more than a decade. The ongoing challenge for VDOT is
to operate, maintain and enhance this investment in order for the NoVa STC to
remain on the leading edge of transportation management.
VDOT's overriding goal is to upgrade and maintain the NoVa
STC automated traffic management system as a state-of-the-art information
technology system whose performance exceeds the expectations of motorists in
northern Virginia.
Therefore, in 2002 VDOT awarded the initial contract for a
two- to five-year, multimillion-dollar project to develop and implement
enhancements to the NoVa STC automated traffic management system. PB Farradyne
is providing system administration and maintenance, evaluating and documenting
the overall system and identifying needed enhancements to the central software
system.
Over the long term, specific enhancements will be
incorporated into the central software and coordinated with ongoing
construction projects in the region. As field devices are added to the system
and software modifications are identified, the software and field hardware will
be integrated into the system.
System serves northern Virginia
The NoVa STC is responsible for an area covering about 80
lane miles that extends from Dumphries, Va., to Washington, D.C., on I-95
(including I-395) and from Manassas, Va., to Washington, D.C., on I-66. The
existing NoVa STC was developed in two phases. The first phase implemented the
initial field hardware subsystem geographically located within the Capital
Beltway (I-495) with a first generation of central software.
The second phase geographically expanded the field hardware
subsystem beyond the Beltway and integrated all the elements of the first- and
second-phase field hardware within one central computer system.
A highly complex system, it monitors and controls a wide
variety of devices and subsystems, including traffic flow condition monitoring
and incident detection, closed-circuit television cameras, variable message
signs, ramp meters, lane control signals, reversible HOV lane control gates and
a tunnel lighting and ventilation control system.
Crisis command center
The NoVa STC played a key role in both the 9/11 and
Beltway-area sniper crises. VDOT was at normal peacetime readiness on Sept. 11,
and a routine rush hour in northern Virginia was just drawing to a close as the
first two airliners crashed into the World Trade Center towers in New York
City. VDOT's Statewide Transportation Emergency Operations Center was in the
process of implementing a statewide terrorism alert via the Virginia
Operational Information System in response to these events when the third aircraft
flew directly over the NoVa STC on route to its impact at the Pentagon.
Following this impact, U.S. military authorities and state
police set up a command post at the STC. The NoVa STC facilitated clearance of
traffic in the Washington, D.C.,
area. Operators immediately coordinated with other jurisdictions to implement
appropriate signal timing plans, suspend construction lane closures and open
high-occupancy vehicle lanes.
Personnel at the NoVa STC coordinated with the state police
and other VDOT districts to mitigate traffic effects, respond to incidents and
help monitor essential infrastructure.
Similarly, during the Beltway-area sniper crisis in October
2002, law enforcement agencies used the NoVa STC as a command center, using the
CCTV for surveillance on area arterials and to coordinate their response in an
effort to capture the snipers.
From system inventory to integration
The NoVa STC project with PB Farradyne comprises six major
tasks: system-wide inventory, updates to staffing requirements, maintenance
support, integration of the Springfield Interchange construction project,
software integration with field enhancement projects and integration of other
software enhancements and modifications.
The project has begun with a thorough review of all existing
system components at the NoVa STC, including central software and hardware. A
multifunctional team is developing the system inventory, verifying the accuracy
of system documentation and setting the foundation of information and processes
necessary to manage and implement changes to the VDOT freeway system.
A copy of the existing system will be built to facilitate
documentation and modifications. In addition to software developers with domain
expertise in freeway systems, the system inventory task requires specialists in
every aspect of intelligent transportation systems: documentation and training,
software configuration management, software quality assurance, systems
engineering and transportation engineering.
At the conclusion of this task, the team will present a
standard Software Configuration Management Plan based on Institute of
Electrical and Electronics Engineers standards. The plan is designed to provide
a platform for effectively managing change.
The project includes an analysis of current NoVa STC
operations and development of recommendations of appropriate staffing levels,
skill levels, training and certification requirements for (1) NoVa STC
operational console positions, (2) central computer operations and
administration, (3) software development and maintenance and (4) other
positions identified by NoVa STC management.
For maintenance support, PB Farradyne has supplied a
full-time systems administrator at the NoVa STC facility during normal work
hours and after-hours as needed since April 2002. The systems administrator
provides on-site technical support to assist operations personnel in operation,
maintenance and troubleshooting of the central NoVa STC system and stand-alone
subsystems.
Integrating Springfield Interchange
The Springfield Interchange (I-95/I-395/I-495) is currently
undergoing a major construction project. The existing NoVa STC system map
display will be updated to reflect the many new ramps and mainline
configurations.
A number of new field devices are being installed, including
closed-circuit television cameras, new radar-type vehicle detection devices and
full matrix variable message signs, which will be integrated into the NoVa STC
automated traffic management system. New device drivers will be written to
communicate with the radar-type vehicle detectors and full matrix variable
message signs in accordance with current National Transportation Communication
for ITS Protocol standards. Graphical user interface software will require
significant updates to accommodate the new terminology and capabilities
associated with these devices.
Radar-type Vehicle Detectors: Existing NoVa STC central
software is designed to gather traffic flow data from Model 170 traffic signal
controllers and remote communication units connected to inductive loop
detectors. A number of modifications are necessary to enable the software to
integrate monitoring and control of new radar-type vehicle detectors in
addition to the Model 170 controllers.
Software modifications will accommodate key differences
between the radar-type detectors and the Model 170 devices, including message
formats, terminology, communication channels and data transmission. Moreover,
the software will be configured to handle both forward-looking and side-fire
radar vehicle detection devices and to inform operators as to which type of
installation is present at a given location.
Full Matrix Variable Message Signs: Existing NoVa STC
central software controls line matrix variable message signs only. With the
addition of full matrix variable message signs at the Springfield Interchange,
authorized VDOT users will be able to create and display messages comprising
text and graphics of varying sizes, taking advantage of the full range of
capabilities of this technology to provide the greatest information value to
motorists. Integration of the new signs will require complex software
modifications to accommodate multiple sign types, including new capabilities to
handle message creation, storage, editing, posting and simulation; downloadable
font creation; sign monitoring and control; and communications.
Software integration with field enhancement projects
A complex series of modifications to the central software
and database also are required to accommodate the system-wide replacement of
coaxial cable with fiber-optic cable. Designed to improve signal transmission,
this field enhancement project began in 2001. Some existing field devices will
be retained, and other devices and control systems will be modified or replaced
to support VDOT's long-term strategy.
For example, closed-circuit television cameras and camera
controllers will be retained, while new multiplexers de-multiplexers and
communication hubs will be installed to support video sharing with other public
entities in the region. Similarly, existing variable message sign controllers
will be retained. Significant changes will be made to other subsystems; in some
cases, hardware and software modifications will facilitate a transition from a
stand-alone control system to permanent integration within the NoVa STC central
computer and database system. These changes include:
Rosslyn Tunnel Control System: Perhaps the most complex of
these subtasks, the central computer software and database will be modified to
support operation of a new, integrated monitoring and control system for the
I-66 Rosslyn Tunnel. The existing system comprises a control push-button panel
located in the NoVa STC, on-site fan control rooms, a carbon monoxide
monitoring system and associated remote telemetry units, lighting systems,
closed-circuit television cameras and a lane control system.
The gas monitoring system, its associated relay interfaces
and the central and remote telemetry units will be replaced, lane control
signals removed and other monitoring and control systems modified to provide a
modern central computer-controlled operation. New interim/testing software will
be created for a temporary personal computer-based replacement for the existing
tunnel control systems. Permanent central computer control software will be
created to integrate the tunnel control system.
Ramp Meter System: The existing ramp metering system inside
the Beltway comprises a remote-control manager in the NoVa STC, 22 remote-control
units, field detector loops and amplifiers, ramp meter controllers and
blank-out message signs. The new system will consist of Model 170E traffic
controllers with cabinets, detector electronics for inductive loops and
existing blank-out message signs, all controlled by a transitional stand-alone
personal computer-based system. Central computer software will be created or
modified as necessary, first to support VDOT in the transition from the
existing ramp meter system to the new field hardware and then to permanently
integrate the ramp meter system.
Traffic Flow and Incident Detection System: Field
modifications affect four traffic flow sites on I-66 and two sites on I-395, as
well as eight sets of reversible lane gates within the Beltway that are
monitored and controlled via remote communication units. These modifications
require the decoupling of central computer software modules related to traffic
flow control and gate control and reintegration into the existing incident
detection system, reconfiguration to accommodate new traffic flow controllers
and their communication assignments and, ultimately, integration of the ramp
meter controller.
I-66 Lane Control Signals: Currently on I-66 between I-495
and U.S. Route 50, the outside shoulder lane in each direction (eastbound and
westbound) is designated for use by through traffic during periods when HOV
lane restrictions are imposed. Approximately 19 new lane signal controllers are
being installed, along with firmware to separate their operation, producing a
unidirectional, one-on-one control system.
Other software enhancements
The final task comprises other software enhancements and
modifications of varying complexity, including integration of field devices
controlling traffic flow on the approaches to the Woodrow Wilson Bridge. In
October 2000, construction began on a 12-lane bridge to replace the existing
six-lane bridge, widen I-95 and Beltway approaches and upgrade four
interchanges to ease area traffic congestion.
VDOT currently operates 18 variable message signs, which are
controlled from a stand-alone personal computer in the NoVa STC. This subtask
is intended to integrate control of these signs into the central system,
providing a user interface identical to that of the other signs in the system.
VDOT also is planning integration of future intelligent transportation system
devices on and around the bridge, including lane-opening gates.
Commitment to ongoing change
The NoVa STC system currently runs under the DEC Unix
operating environment. A state-of-the-art operating environment at one time,
new hardware is no longer available for this system, and the newest versions of
applications such as the Oracle database system and commercial off-the-shelf
software tools are not supported. Therefore, VDOT is considering migrating
toward a newer environment, such as Windows 2000 or Linux. Essential
characteristics of any new operating environment would include compatibility
with existing stand-alone systems, ongoing support, flexibility, maintainability
and upgradeability.
As our highway systems become more congested at the same
time the public's expectations of service increase, remaining on the leading
edge of intelligent transportation systems technology is not an option, but a
requirement for transportation managers and engineers. Rapid improvements in
hardware and software require the integration of a complex array of devices and
subsystems, both in the field and in the traffic control center. This takes an
effective team effort among transportation managers, systems administrators and
operators, field contractors and specialists in every aspect of freeway systems
from software development to traffic management and engineering.
Maintaining a state-of-the-art information technology system
that is reliable, effective and as easy as possible for system operators and
administrators to use requires a commitment to ongoing change. With this
project, VDOT has extended its commitment to developing and maintaining a smart
traffic center that exceeds the expectations of the public in northern
Virginia.
TME
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