Montgomery County, Maryland forms the northwestern border of Washington, D.C.
covering an area of approximately 500 square miles. Montgomery County has a
population of 750,000 with 65 percent of the population working within the
county. There are over 2000 miles of roads in Montgomery County with three of
the heaviest traveled interstates (1-270, 1-370, and I-495) in Maryland. Because
of an excellent job base, thousands of people come into the county each day to
work, attend to business, or shop. Typical average weekday traffic on certain
sections of the interstate system can reach 130,000 vehicles, and on typical
major arterials can reach 70,000 vehicles. Montgomery County operates Ride-On, a
250 bus transit system that connects to the Washington D.C. area bus and
Management of this substantial and growing transportation system has been a
priority in Montgomery County. Montgomery County's Department of Transportation
is responsible for managing and operating the transportation system. The
Department of Transportation has been aggressive in implementing the latest
technologies to help manage the transportation system.
Advanced Transportation Management System Transportation Management System In
1980, Montgomery County's Department of Transportation started the construction
of a computerized signal system. The real time computerized signal system has
grown from controlling 10 intersections to the present system that controls over
600 traffic signals.
The computerized signal system has been enhanced several times over the past
13 years to provide improved incident and transportation management features. In
1990, Montgomery County's Department of Transportation, Division of Traffic
Engineering began the design of a system that would support the management of
the transportation system into the 21st century. The system would be known as
the Advanced Transportation Management System (ATMS). The ATMS would be composed
of multiple subsystems controlled and monitored from common transportation
workstations. The ATMS would be open architecture to allow for growth and
integration of systems from multiple vendors. May 1992, Montgomery County
entered into a contract with Automatic Signal/Eagle Signal to develop and
implement the ATMS.
As of the date of this article, the ATMS was being installed in Montgomery
County's transportation Management Center (TMC) with acceptance testing to start
in February, 1994.
The ATMS will include:
- Advanced traffic responsive traffic signal control
- Automated sign control system.
- 200 camera video surveillance system.
- Sophisticated electronic transportation monitoring systems.
- Time critical geographic information system (GIS)
- Automated transportation information system.
- Integrated transit and traffic operations.
- GPS and ocher technologies based vehicle tracking system.
- Automated incident management system.
- Aerial surveillance operations.
- Automated integration with police / fire computer aided dispatch systems.
Montgomery County has been divided into six areas for implementation of ATMS
related field equipment. The first area was started in 1992 with anticipated
completion by early 1995. The remaining five areas will be implemented on a two
year schedule per area depending on funding. Implementation of the field
hardware will be done in conjunction with the construction of a 300 mile fiber
optic based communication system. The fiber optic system will enhance the
Department of Transportation's existing 300 plus mile twisted pair copper
Transportation Incident Management Program
Montgomery County has a transportation management program. This program combines
the capabilities of the ATMS and the coordination of activities between police,
fire and rescue, and transportation agencies within Montgomery County and
Maryland. Montgomery County has formed a Transportation Incident Management team
(TIM) composed of representatives from the Department of Police, Department of
Fire and Rescue, Department of Environmental Protection, and the Department of
Transportation. TIM meets on a regular basis to discuss and implement
improvements to the county's incident management program.
Transportation Management Center
Montgomery County's Transportation Management Center (TMC) houses and operates
the ATMS and has direct connections to police and fire and rescue dispatch
facilities. Ride-On transit dispatch is located adjacent to the existing TMC.
Montgomery County is in the initial design stage of a new TMC which is planned
to house within one facility traffic operations, transit operations, highway
maintenance operations, and police and fire support personnel.
The existing TMC is staffed from 6:00 AM to 1 1:00 PM 365 days a year. As
staffing allows the TMC is planned to be staffed on a 24 hour basis.
Aerial Surveillance Program
As part of Montgomery County's transportation management program an aerial
surveillance program was started in 1989. The aerial surveillance program was
the result of a continuing effort by the Montgomery County Department of Police
and the Department of Transportation to improve transportation management in the
county. A test of using an aircraft to monitor AM and PM rush hour traffic was
funded by the Department of Transportation.
Initially a traffic engineer would fly in a contracted airplane with a
contracted pilot each morning and evening rush hour and would use a portable
radio to radio problems to the Transportation Management Center. Within a few
months of the start of the project the Department of Transportation entered into
a contract to lease an airplane on a 24 hour basis and the Department of Police
assigned two Sergeants with existing commercial pilot licenses to fly the
airplane. A radio pack was designed and constructed by county personnel to
provide multiple communication frequencies that allow the observer to contact
most police, fire, and transportation agencies in the Washington D.C. area
including state highway and police agencies.
In 1992, because of budgetary reasons the Montgomery County Department of
Police had to withdraw the two pilots from the project. The Department of
Transportation contracted pilot services with the company supplying the
aircraft. The project has been solely operated by the Department of
Transportation since 1992.
Montgomery County uses a single engine high-winged airplane. The airplane was
chosen over a helicopter because of operating costs. The airplane can be
operated for approximately $80 per hour versus $300 per hour for a helicopter
with similar performance capabilities. It was decided that for 99 percent of and
landing capabilities of a helicopter. Five years of experience has proven this
to be true.
Over the past five years the airplane used by Montgomery County has chanced
to meet the requirements of the county. Initially, the county leased a Cessna
172, a small four passenger airplane with limited room for personnel, equipment
and passengers. In 1990, the county contracted for a Cessna 182. The Cessna 182
is a larger four place airplane with sufficient room for personnel, limited
equipment, and passengers. The Cessna 182 was replaced in the late 1993 with a
Cessna 206. The Cessna 206 is a six place airplane with excellent load carrying
capabilities. The Cessna 206 was required to be able to carry the additional
equipment associated with on board live video broadcasts.
The aerial surveillance project has been a critical part of the Department of
Transportation's transportation management program. On a typical flight the
airplane either finds or quickly responds to incidents that impact the
transportation system. The observer contacts the appropriate authority to
respond to the problem, notifies the TMC to adjust traffic signals, etc. in the
area of the incident, and directly notifies the airborne radio traffic reporters
of the problem. The airplane is known as MC-10.
MC10 performs on a regular basis traffic management functions, police
surveillance, environmental protection activities, assists fire and rescue in
locating fires in the rural and other hard to access areas. MC-10 is used for
still and video photography.
Live Aerial Video Project
Montgomery County determined that the aerial surveillance project could be
further enhanced if live video could be sent from the airplane to the
Transportation Management Center and other agencies.
Providing a live video picture of what was happening to the TMC would help
managers on the ground make appropriate decisions as they would have the
"big picture" which cannot be readily described over the radio or by
land line. Multiple ground units would have to describe a situation and their
description is usually controlled by what they can actually see, which is very
limited on the ground.
In July, 1991, after several meetings the State of Maryland, Montgomery
County, the State of Virginia, and Fairfax County, Virginia delivered a proposed
demonstration project for live aerial video to the Federal Highway
Administration (FHWA). The demonstration project would be divided into stages,
the first would be to test live video from a helicopter and from a fixed wing
airplane. Other stages were proposed enhancements to the information gathered by
the aircraft. Fairfax County, Virginia would install a video camera system on
one of its police helicopters and Montgomery County, Maryland would implement
live video capabilities in its fixed wing airplane.
After FHWA approved a 50/50 funded demonstration project for stage one,
Montgomery County Department of Transportation prepared specifications and
advertised through the normal bid process for a contractor to supply and
implement the specified video system. The normal bid process in Montgomery
County takes six months. Because of limited knowledge by the county's
procurement office of the type of company that would be qualified and improper
advertisement of the bid the county received no bids. The Department of
Transportation was then authorized by the county's Chief Administrative Officer
to contact capable vendors directly and obtain bids. Four companies submitted
bids and the Department of Transportation negotiated a contract with the
qualified lowest bidder. A contract was signed in April, 1993 with N-Systems
Incorporated (NSI) located in Columbia, Maryland.
Some equipment was ordered and other components of the system were designed
and manufactured by NSI.
During the Summer and Fall of 1993 installation and testing of the system
began. Testing had to be stopped when the county upgraded the airplane from the
Cessna 182 to the Cessna 206. As part of the contract for the Cessna 206 a new
console was to be constructed by the airplane contractor and installed in the
airplane. This console would contain the multiple radios, video monitor, S-VHS
recorder, GPS receiver, and microwave transmitter. The console was completed at
the end of December, 1993. As of the date of this article, the console is
temporarily installed in the aircraft with permanent installation scheduled by
the end of January, 1994.
Montgomery County's aerial surveillance system is composed of:
- Microwave transmitter
- GPS receiver
- Color video camera
- Color video monitor
- S-VHS player / recorder
- Microwave antenna
- Transportation Management Center
- Microwave receiver
- Automated tracking antenna
- Antenna control system
- Color video monitors
- S-VHS editing system
- Portable Ground Transmit and Receive System Transmit
- Microwave transmitter
- Microwave antenna
- Color video camera
- Receive (3 sets)
- Microwave receiver
- Microwave antenna
- Color monitor
- S-VHS player recorder
The video system provides the capability to automatically track the airplane by
sending the actual location of the airplane, as determined by the global
positioning system (GPS) receiver in the airplane, to the receive and control
equipment located in the Transportation Management Center. The control equipment
in the TMC automatically points the tracking antenna located on the roof of
Montgomery County Government's Executive Office Building (EOB), a 15 story
high-rise located in Rockville, Maryland. The TMC is located on the 11th floor
of the EOB. The EOB is located near the geographic center of Montgomery County.
The microwave system used in this project requires the tracking antenna to track
within 14 degrees of the airplane to maintain a usable picture and to be able to
receive the GPS data.
Should the automatic tracking fail the antenna on the roof of the EOB can be
positioned manually from the TMC through a touch screen control unit. Audio can
be sent over the microwave system from the airplane to the TMC.
In the airplane an industrial grade color video camera is mounted so as to
aim out of the side window behind the observers seat. The observer can monitor
the video system and record what the camera is viewing. An additional monitor is
mounted so the pilot can also see what the camera is viewing and adjust the
track of the airplane accordingly.
The portable transmitter system provides the county the capability to
transmit live video from the scene of an incident or other activity directly
back to the TMC. The portable system uses the same type of microwave transmitter
as is installed in the airplane. A directional microwave antenna is mounted on a
tripod and is aimed in the direction of the tracking antenna on the roof of the
EOB. Since the portable unit is using the same antenna as the airplane both
systems can not be operational at the same time. When the ground unit is in use
the staff in the TMC moves the roof mount antenna until an acceptable microwave
signal is received.
The ground based portable receivers can receive transmissions from the
airplane or from the ground based transmitter. The portable receiver antenna can
be used as a directional antenna to receive the signal from the airplane when
the airplane is in the distance or can be pointed straight-up and will receive
transmissions from the airplane as it circles overhead.
The portable units will be used by the Maryland State Highway Administration,
Montgomery County Department of Transportation, and one unit will be installed
in Montgomery County's Police/Fire and Rescue Command Bus. The Command Bus is
sent to major incidents to serve as an on-scene command and communication
As part of Montgomery County's automated transportation information system
the video and audio received from the airplane or ground unit can be sent over
the government network to other agencies. The video and audio can also be sent
from the TMC over the subscriber cable television system into homes and
businesses. The on-air television broadcast stations are presently connecting to
the TMC's system and will be able to receive the same video and audio and then
retransmit as part of their news broadcasts. The airborne and portable video can
be combined with video from the fixed video surveillance system.
Preliminary testing indicates the airborne system performs exceptionally well
as long as a good signal can be received. Initial tests indicates that the video
signal can be received from the airplane while it is over any point in
Montgomery County as the airplane flies at its normal altitude of 1000 feet
above the ground. There are certain areas of the county where other microwave
signals are interfering with the signal from the airplane. This may be addressed
by going to another frequency. Tests of the portable receivers have been very
successful. The directional mode allows personnel on the ground to track the
aircraft manually in the distance. The distance the airplane can be received is
dependent on the altitude it is flying and if any solid objects or terrain block
the microwave signal.
The portable ground transmitter works well as long as terrain or solid
objects do not block the microwave signal. Testing has been successful from
distances up to 3 to 4 miles even though the antenna is mounted on a tripod
sitting on the ground. Extended distances and increased areas of coverage could
be possible with a 40 foot telescoping mast for the antenna. As part of
Montgomery County's transportation management program an incident management and
transportation analysis van is planned. This van will be specified with a
telescoping antenna and other equipment to integrate with the airborne and
ground based video system.
Presently, the camera mounted in the airplane is not stabilized so image
steadiness is dependent upon how turbulence impacts the airplane. When the
camera is zoomed in closer any movement is exaggerated. The first stage of the
demonstration project was to demonstrate the use of live video and how well a
microwave signal can be sent from an airplane to a traffic management center.
Improvements to the video image can be greatly enhanced by installing a
gyro-stabilized camera mount.
Montgomery County has been reviewing and testing a stabilized video system
which can be readily adapted to the existing microwave system and could be
mounted on the Cessna 206 as it was recently certified and tested on a Cessna
172. The stabilized system is manufactured by Wescam, a major supplier of
stabilized film and video equipment used by the motion picture and television
industry. The system mounted on the Cessna 172 has been tested by Montgomery
County personnel. The Wescam system has been used to track individual vehicles
from the Cessna 172 and will readily allow the operator to fix the camera on an
incident or intersection. The stabilization maintains a steady image even in
Montgomery County's aerial surveillance program is critical to the county's
transportation management program. The airborne video system greatly enhances
the aerial surveillance program. The airborne video system provides ground
personnel, including decision makers, the ability to make educated decisions on
what actions should be taken because they see the total impact of an incident or
event on the transportation system. The video images can be shared with other
agencies and the media. This sharing of the "big picture" helps other
agencies respond to situations and allows Montgomery County Government and the
media to disseminate improved information to the public.
Montgomery County has just started testing the airborne and ground based
system. Initial findings indicate the system can be enhanced by installing a
gyrostabilized camera. Low light capabilities could be added for night time
operation. Fixed remote receiver sites would improve reception in those areas
with interfering signals.
Even the initial tests have proven that "live" broadcast quality
video from an airplane can be done.
The "live" video can be a valuable tool to help manage traffic on a
daily basis and during incidents or special events.
Montgomery County plans to complete its evaluation of the airborne system
during the first quarter of 1994 with results forwarded to the Federal Highway
Administration soon after. Montgomery County hopes to work with the State of
Maryland and the Federal Highway Administration to further enhance the aerial
For further information on Montgomery County's Advanced Transportation
Management System or the aerial surveillance program please contact:
Mr. Emil Wolanin
Telephone: (240) 777-2190