VASCAR
Encyclopedia
VASCAR is a type of device for calculating the speed of a moving vehicle. The first VASCAR device was created in 1966 by Arthur Marshall. It is used by police officer
s to enforce speed limits
, mainly in jurisdictions (such as Pennsylvania
) where RADAR
and/or LIDAR
are illegal, or to prevent detection by those with radar detector
s.
This technique can also be used to determine a vehicle's speed from helicopters and other aerial platforms, making it easier to secure a conviction.
A 1991 study by the National Highway Traffic Safety Administration
found that VASCAR-plus units produced errors of less than 2 mph if used correctly.
in 1966. He was inspired to create the device after watching a police car driving dangerously trying to pace a speeder. The original version of the device was entirely mechanical, using a governed motor and a gear system to move a pointer to the correct speed value. Subsequent versions used a microprocessor to perform the speed calculations. By 1968, the device was in use in North Carolina
, Indiana
, Kentucky
, and New York
. In 1971, Marshall formed a company, Traffic Safety Systems, Inc., to market the device. After his death, Traffic Safety Systems was purchased by Power Systems & Controls, Inc., which had long manufactured the devices. They continue to produce similar devices under the name VASCAR-plus.
Police officer
A police officer is a warranted employee of a police force...
s to enforce speed limits
Speed limit enforcement
Speed limit enforcement is the action taken by appropriately empowered authorities to check that road vehicles are complying with the speed limit in force on roads and highways. Methods used include roadside speed traps set up and operated by the police and automated roadside 'speed camera'...
, mainly in jurisdictions (such as Pennsylvania
Pennsylvania
The Commonwealth of Pennsylvania is a U.S. state that is located in the Northeastern and Mid-Atlantic regions of the United States. The state borders Delaware and Maryland to the south, West Virginia to the southwest, Ohio to the west, New York and Ontario, Canada, to the north, and New Jersey to...
) where RADAR
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
and/or LIDAR
LIDAR
LIDAR is an optical remote sensing technology that can measure the distance to, or other properties of a target by illuminating the target with light, often using pulses from a laser...
are illegal, or to prevent detection by those with radar detector
Radar detector
A radar detector is an electronic device used by motorists to detect if their speed is being monitored by police or law enforcement using a radar gun. Most radar detectors are used so the driver can reduce the car's speed before being ticketed for speeding...
s.
Operation
A VASCAR unit couples a stopwatch with a simple computer. An operator records the moment that a vehicle passes two fixed objects (such as a white circle or square painted on the carriageway) that are a known distance apart. The vehicle's speed is then calculated by dividing the distance by the time.This technique can also be used to determine a vehicle's speed from helicopters and other aerial platforms, making it easier to secure a conviction.
A 1991 study by the National Highway Traffic Safety Administration
National Highway Traffic Safety Administration
The National Highway Traffic Safety Administration is an agency of the Executive Branch of the U.S. government, part of the Department of Transportation...
found that VASCAR-plus units produced errors of less than 2 mph if used correctly.
History
VASCAR was invented by Arthur Marshall, a real-estate investor living in Richmond, VirginiaVirginia
The Commonwealth of Virginia , is a U.S. state on the Atlantic Coast of the Southern United States. Virginia is nicknamed the "Old Dominion" and sometimes the "Mother of Presidents" after the eight U.S. presidents born there...
in 1966. He was inspired to create the device after watching a police car driving dangerously trying to pace a speeder. The original version of the device was entirely mechanical, using a governed motor and a gear system to move a pointer to the correct speed value. Subsequent versions used a microprocessor to perform the speed calculations. By 1968, the device was in use in North Carolina
North Carolina
North Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...
, Indiana
Indiana
Indiana is a US state, admitted to the United States as the 19th on December 11, 1816. It is located in the Midwestern United States and Great Lakes Region. With 6,483,802 residents, the state is ranked 15th in population and 16th in population density. Indiana is ranked 38th in land area and is...
, Kentucky
Kentucky
The Commonwealth of Kentucky is a state located in the East Central United States of America. As classified by the United States Census Bureau, Kentucky is a Southern state, more specifically in the East South Central region. Kentucky is one of four U.S. states constituted as a commonwealth...
, and New York
New York
New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...
. In 1971, Marshall formed a company, Traffic Safety Systems, Inc., to market the device. After his death, Traffic Safety Systems was purchased by Power Systems & Controls, Inc., which had long manufactured the devices. They continue to produce similar devices under the name VASCAR-plus.
Similar Devices
While the name VASCAR is no longer trademarked, Power Systems & Controls holds the trademark to VASCAR-plus. Other companies sell similar, though non-VASCAR-branded, systems. For example, under the category "electronic speed timing devices (nonradar), which calculate average speed between any two points", the Pennsylvania Department of Transportation authorizes two devices in addition to the various VASCAR-plus models: the Tracker, by PATCO, and the V-SPEC, by YIS/Cowden Group.See also
- Automatic number plate recognitionAutomatic number plate recognitionAutomatic number plate recognition is a mass surveillance method that uses optical character recognition on images to read the license plates on vehicles. They can use existing closed-circuit television or road-rule enforcement cameras, or ones specifically designed for the task...
- SPECS (speed camera)
- Mean Value TheoremMean value theoremIn calculus, the mean value theorem states, roughly, that given an arc of a differentiable curve, there is at least one point on that arc at which the derivative of the curve is equal to the "average" derivative of the arc. Briefly, a suitable infinitesimal element of the arc is parallel to the...
(The car's instantaneous speed must equal the average speed at least once on the observed time interval. Therefore, if the average speed calculated is above the speed limit, the car must have been speeding at least once within the marked locations.)