Aircraft

More recently, the police have taken to the sky to monitor the roads. Speed tracking from the sky is actually a combination of police units on the ground and in the airplane.

Roughly 20 states currently use aircraft for enforcing speed limits. The aircraft method is still not very popular in many areas because it is quite expensive due to maintenance and operating costs.

Although this method seems fairly high-tech and somewhat complicated, it still uses the basic equation that many other methods use: speed is equal to distance divided by time.

The police paint stripes on a portion of the road. The distance between the stripes is measured and taken into account. A police helicopter then hovers over the marked section of the road and determines a vehicle's average speed using the VASCAR method.

VASCAR devices are usually attached to road policing vehicles and have recently been installed in aircraft. VASCAR works like a stopwatch, using the distance data feed from an aircraft to measure a moving target's speed.

VASCAR stands for Visual Average Speed Computer. The method calculates speed by measuring the distance between the two markers painted on the road and dividing it by the time the target takes to travel between the two markers.

With this method, the police officer in the aircraft switches on VASCAR as a vehicle crosses into a pre-measured section of the road and then switches the device off when the vehicle exits the section. The unit then displays the vehicle's speed to the officer.

After receiving the reading, the officer in the aircraft informs his fellow officers on the road of each vehicle's speed. If a driver is caught exceeding the speed limit, the ground officers stop the vehicle and issue the driver a ticket.

This method is generally very accurate and effective in catching speeders. However, since it requires the aircraft to hover over a section of a road, truckers commonly spread word through their radio systems that there is law enforcement in the area.

The aircraft used is generally a high-wing design that gives the law enforcement agents a clear, unobstructed view of the ground. Since the aircraft is rather pricey, the police often use it for other operations, including:

• Drug eradication activities.
• Emergency transport.
• Traffic monitoring.
• Surveillance.
• Other law enforcement programs.