Describe the correlation between speed (momentum) & kinetic energy
Kinetic energy increases much faster (at a greater rate) than does speed (momentum)
Name the two types of speed laws:
1) Basic (prima facie) speed limits
2) Absolute Speed Limits
Describe how the 85th percentile is conducted:
The speed of all vehicles is determined at a specific location & time. The statistics are studied to determine the pace (10mph segment containing 60% to 70% of the total vehicles) and the speed at which a cumulative total of 85% of the vehicles are traveling
How can a police officer prove an alleged violation of "speed too fast for conditions" in a court of law?
By conducting a speed study (at the same time, location & conditions) which shows the pace and the 85th percentile
What procedure is an officer accomplishing during Quick Pace Timing? (QPT)
Pacing a vehicle and timing his following distance by use of a stopwatch
In order to establish a tracking history it is essential that an officer accurately estimates both ____________ & ______________
distance (range) & speed (velocity)
When using time-distance formulas what two items must an officer certify?
The timing device (ie:stop watch)
& Device used to measure distance (ie. roller tape)
Radio and light waves interact with the enviornment in one of three ways explain:
A. Reflect
B. Refract (Diffuse)
C. Absorb
Explain the doppler shift or the Doppler frequency
The difference between the transmitted frequency and the recieved frequency
Continious wave, doppler traffic radar is unable to determine ________
range (distance)
A radar signal relected off a target which is moving towards the radar will be _______ and returned at a ______ frequency
compressed & higher
Name three factors which determine the reflectivity of a target vehicle
a) size
b) shape
c) vehicle composition
Name two factors which determine target selection within the main power beam
A) location from the axis of the main power beam
B) distance from the transmitter
Name three functions of the doppler audio
A) Assists with the inital observation & identification of the target vehicle
B) assists with target selectivity problems
C) Assists in identifying possible sources of interference
Which of the following statements is most accurate when describing identification of vehicles as they pass through the radar beam:
B)
Which of the following statements is most accurate when describing the inverse square law?
C)
Which of the following statements is most accurate in describing contour lines of sensitivity?
A)
Describe three methods to control the radar range in the stationary mode:
1. Sensitivty (range) control functions can be turned down
2. tilting or angling the antenna
3. Use of the environment such as hills and curves
Name three important features to consider when mounting a radar antenna:
1. Securely mounted and positioned away from air bags
2. Position the antenna to prevent feedback from the counting unit
3. Position the antenna in a location of minimal distortion
Name four methods of testing a radar unit:
1. Light segment test
2. Internal Circuitry test
3. External turning fork test
4. Known speed test
Name four tuning fork tests that should be conducted on a dual antenna radar:
1. Front antenna- stationary mode
2. Front antenna - moving mode
3. Rear Antenna - stationary mode
4. Rear antenna - moving mode
Name the three areas of emphasis for stationary radar tracking history:
1. Visual Observation
2. Audio Confirmation
3. Radar Verification
Name two reasons why it is important to know what external sources may affect radar
1. understanding radar effects helps to elimate possible sources of interference
2. understanding radar effects helps to disregard erroneous readings
Give three examples of radio frequency interference (RFI)
1. RFI from transmitters such as police and business radios
2. RFI from light sources such as mercury vapor, neon, and fluorescent lights
3. RFI from power sources such as power substations and high voltage transformers
Name three procedures to elimate of effectively reduce heat build-up in a radar:
1. mount the counting unit in a location other than the dash
2. use a sun shade when the patrol car is parked unattended
3. operate the air conditioning through the defroster vents
Radar effects are usually weak signals, short in duration, and lack _____________
supportive evidence (tracking history)
Why are active radar jamming devices illegal?
They are not licensced by the FCC to transmit on frequencies reserved for police traffic radar
If a radar operator questions the indicated target speed, what enforcement action should be taken?
None
Describe the functions of a low doppler & high doppler in moving radar?
Low doppler is the patrol speed determined from the signal bouncing off the road
High doppler is the relative speed between the patrol car and the target vehicle
Define the shadowing effect as it applies to moving radar:
Shadowing effect is when the low doppler frequency is reflecting off a moving behicle directly ahead of the patrol car, thus resulting in an erroneous patrol speed calculation
When staring from a parked position in heavy traffic and operating a radar in the moving mode, what often happens to the low Doppler?
Slow moving vehicles ahead of the patrol car cover the hot spot and the radar does not recieve a low Doppler frequency. On approach of a target vehicle the patrol speed (low doppler) will be displayed as the relative speed b/w the patrol car and the target vehicle. This is known as low-speed combining
Describe three procedures to correct low-speed combining
1. Activate patrol speed blank
2. Tilting the antenna
3. Cycling the radar from moving to stationary then back to moving mode
The high doppler circuit on radar processes what information?
The relative speed b/w the patrol car and the target vehicle
Give three examples of harmonic signal interference:
1. pulsating signal amplitude effect
2. multi-path signal effect
3. own speed capture effect
Name the four areas of emphasis for moving radar tracking history:
1. Visual observation
2. Audio Confirmation
3. Radar Verification
4. Speedometer verification
Describe two incidents when an officer would utilize patrol 5/20: (one incident for patrol 5, one incident for patrol 20)
Patrol 5 would be utilized when entering a school zone and traveling under 20 mph
Patrol 20 should be utilized during routine patrol at speeds above 20 mph to reduce shadowing effect
When utilizing same lane tracking, two precautions must be observed. Describe:
1. At least a 5 mph difference in relative speed from the patrol car to the target vehicle
2. There should not be excessive traffic (unless a DSR radar is used)
Track Thru Locking (TTL) is an important feature during the moving mode. Why?
Track Thru Locking (TTL) allows an officer to monitor the patrol vehicle speed after a target vehicle speed has been locked in the middle window (continious tracking). When the officer slows by 10 mph to pursue the violator (kustom radar) or stops the patrol car (stalker radar) the radar then displays the patrol speed at the time the target vehicle was locked
Describe the relationship b/w the fastest vehicle mode and a complete tracking history
operating in the fastest vehicle mode, observing all traffic, and not locking onto a target vehicle, allows an officer to obtain a complete tracking history of the target vehicle and all other vehicles in the immediate area
List five safety guidelines for the operation of police traffic radar:
1. do not point the radar toward the body
2. Utilize the RF hold feature when not in use
3. Do not position anyone within two feet directly infront of the antenna
4. utilize porper antenna mounting brackets
5. position the antenna away from reflective objects in the interior of the vehicle
Why is the photo radar beam angled at approximately 22 degress across the roadway?
To prevent photgraphing a target behicle which is too far from the camera for a positive identification of the front license plate and an unobstructed view of the driver
Why has the use of photo radar been restricted by several states?
It has sometimes been viewed as a source of generating revenue rather than public safety
Police traffic lidar utilizes what two methods to determine speed:
1. the pulse principle
2. the speed of light constant
What four tests must an officer perform to prepare a lidar case for court?
1. known distance
2. known speed
3. slight alignment
4. technician certification
Explain tracking history as it applies to the operation of lidar:
1. visual observation of the target- estimate speed and range
