NHTSA Speed measuring devices
What is 4511.091?
Arrest or citation of driver based on radar, timing device or radio message from another officer.
State vs. Hanson was the first significant case to address the issue of moving RADAR operation. It established that:
As stationary RADAR, the operator ust have significant experience and traning; the RADAR must be in working order. The RADAR device is to be used in an area where road conditions create a minimal possibility of distortion. The patrol speed must be verified. The RADAR device's accuracy must be tested within a reasonable time both before and after the arrest.
Any speed offense has 4 elements. It is essential to establish every element in order to obtain a conviction. These 4 elements are:
Driver, vehicle, location, speed
Detection devices reduce speed enforcement effectiveness by giving drivers advanced warning allowing time to slow down and avoid getting caught, such as:
Flashing headlights, cb radio, radar/lidar detectors
(LIDAR) Visual observation:
Identify target, estimate speed, estimate distance, and check environment
(RADAR) Visual observation:
Identify target, estimate speed, estimate distance, and check environment
LIDAR is an acronym for:
Light detection and ranging
Key factors to consider when choosing a site to conduct speed enforcement activities:
Need and safety
(RADAR) Audio confirmation:
Pitch and clarity
The word RADAR is an acronym. It stands for what?
Radio detecting and ranging
RADAR "decision making" is affected by 3 factors. What are they?
Reflective capability, position, and speed.
Honecutty vs. Commonwealth dealt with the qualifications a RADAR operator must have to produce admissible speed measurements. An operator must be able to:
Set up the RADAR unit properly, test the device properly to verify that it is working accurately, and read the device properly to obtain a true speed measurement.
(LIDAR) Target speed confirmation:
Steady or multiple readouts, readout consistent with visual observation
(LIDAR) Audio confirmation:
Target acquisition tone
Honeycutt vs. Commonwealth also addressed the question of how it can be verified that the RADAR speed measurement came from the target vehicles:
The vehicle in question must be the closest to the RADAR, it must be out front of other vehicles and well separated from them, the oeprator should have made a visual estimate of the vehicle's speed, and the RADAR speed measurement should be close to this estimate
True or false: LIDAR devices are completely safe for human exposure. LIDAR devices emit less power and energy than a television remote, flashlight and the popular laser tag games.
True
True or false: RADAR wave energy is transmitted by the antenna in a cone shaped pattern resembling a flashlight's beam.
True
True or false: a stationary RADAR signal that strikes a motionless target will return a reflected signal at the same frequency that is being transmitted
True
True or false: an absolute speed law states: it is unlawful to drive a vehicle on public roadways at a speed greater than the specified limit.
True
True or false: because of the width of the beam, RADAR cannot focus on one single target at any significant distance
True
True or false: doppler principle stated: "when there is relative motion between 2 objects, 1 which is transmitting an energy wave, the frequency of the signal as received by the other object changes due to the relative motion."
True
True or false: higher speeds increase the time and distance required to stop a vehicle.
True
True or false: higher speeds make it more likely that a crash will occur.
True
True or false: higher speeds overwhelm a driver's capability by limiting his reaction time.
True
True or false: if there is relative motion (toward or away) between a RADAR and an object, the frequency of the reflected signal will be different than the frequency of the transmitted signal.
True
True or false: in Royals vs. Commonwealth, the Virgina Court cited that test of accuracy of a RADAR device should be done each time the device was set up at a particular location during a day shift.
True
True or false: in State vs. Dantonio judicial notice was first taken of the Doppler Principle. This eliminated the need to have experts testify to the fundamental basis of RADAR speed measurement during every prosecution that involved police traffic RADAR.
True
True or false: in State vs. Tomarelli judicial notice was first taken of the tuning fork method as a reliable test of RADAR device accuracy.
True
True or false: the LIDAR signal as with all electromagnetic energy will only be altered by being reflected, refracted, or absorbed
True
True or false: the LIDAR signal posses the same 3 distinguishable characteristic as other forms of electromagnetic wave energy, signal speed, wavelength and frequency.
True
True or false: the angular effect can only result in a stationary RADAR device perceiving speed less than the target vehicle's true speed.
True
True or false: the basic speed law states: it is unlawful to drive a vehicle on public roadways at a speed greater than is reasonable and prudent under existing conditions.
True
True or false: the higher the speed, the more energy present during a crash.
True
True or false: the most important characteristic of a moving RADAR device is that measures two speeds at the same time: the speed of the patrol vehicle relative to the stationary terrain (the roadway), and the relative speed at which a target vehicle is approaching or going away from the moving patrol vehicle.
True
True or false: the optimum terrain for RADAR enforcement is a straight, level roadway. Police traffic RADAR will not normally display vehicles around a curve or over a hill.
True
True or false: the range, or maximum distance, at which a reflected signal can be interpreted by RADAR device depends on the sensitivity of the antenna receiver.
True
True or false: the velocity of all radio signals is a constant - the speed of light, which is about 186,282 miles per second, or 30 billion centimeters per second.
True
True or false: with a stationary RADAR beam transmitted down a roadway on which vehicles are either approaching or moving away: all that can be determined is how fast the target and RADAR device are moving relative to each other.
True
LIDAR tracking history:
Visual observation, audio confirmation, and target speed confirmation
Radar tracking history:
Visual observation, audio confirmation, and target speed confirmation
Every radio signal has 2 characteristics that distinguish it from every other signal.
Wavelength is the distance from the beginning of the peak to the end of the valley. Frequency is the number of the waves sent out in the signal during 1 second of time.
There are 3 FCC assigned radar frequency bands. What are they?
X band, K band, Ka band
In order to improve the effectiveness of speed enforcement, officers must:
1. Observe more speed violations. 2. Apprehend more violators 3. Secure more convictions
Police RADAR devices should be tested according to individual manufacturer's specifications. Based upon current case law, the following tests are required:
Internal circuits test, light segment test, external tuning fork test, patrol speed verification test, and subsequent tests for accuracy
(RADAR) Target speed confirmation:
Steady readout, readout consistent with visual observation, verify patrol speed (moving), speed discrimination test (same direction moving)
True or false: in Thomas vs. City of Norfolk, the Virgina Court relaxed its previous decision in Royals vs. Commonwealth and cited that the minimum criteria for testing was to be at the beginning and at the end of a duty shift.
True
True or false: once transmitted, the length of the beam is infinite unless it is reflected, absorbed, or refracted by some object in its path.
True
True or false: speed measuring devices improve speed enforcement efforts by providing an accurate measurement of a driver's speed.
True
True or false: the 2 types of speed laws are the basic speed law and the absolute speed law.
True
True or false: the LIDAR operator must perform all required accuracy checks prior to beginning enforcement operation as manufacture's specifications. Accuracy checks should also be done at the end of duty shift.
True
