NC RADAR State Exam Questions And Answers Verified 100% Correct

NC RADAR State Exam Questions And Answers Verified 100% Correct The probability of a fatality in a crash roughly doubles as traveling speed increases from ___ to ___ mph , and doubles again as speeds go to ____ - ANSWER 45mph to 60 mph, 70mph The projected 9% fatality increase translates into what? - ANSWER 3500 Lives What is one possible explanation as to why motorists speed? - ANSWER A motorist on the highways sees everyone else exceeding the speed limit, and getting away with it, and figures "why shouldn't I?" A key to voluntary cooperation to speed limits lies with who? - ANSWER Law Enforcement. Motorists must be reminded that the laws are there and will be enforced National Highway Safety Systems Designation Act - ANSWER Signed into law by Congress on November 28, 1995. This Act, among other things, established the National Highway Systems and eliminated the Federal mandate for the National Maximum Speed Limit. In doing so, ended a period of more than 20 years of Federal involvement in the states establishment of speed limits and ended the requirements for states submission of speed compliance data to the Federal Highway Administration In NC, speeding remains a major factor in highway deaths and serious injuries. In 2009, the National Highway Safety Administration Traffic Safety Facts (TSF) illustrated what? - ANSWER That speed attributed to 39% of all highway deaths. We find in the TSF for 2014 in NC that 38.7% of all highway deaths were attributed to speed. On a national level, the TSF also indicates that for the full year of 2013, 42% of speeding drivers in fatal crashes also had a blood alcohol concentration of .08 grams per deciliter or higher It was known that radio waves could be reflected from solid objects as long ago as 1886, but what brought about serious research and development of RADAR? - ANSWER The threat of war in Europe in the late 1930s Range information can be expressed in what? - ANSWER Yards or feet The antenna of the RADAR unit does what? - ANSWER Shapes, forms, transmits, and receives microwave energy The energy transmitted by an antenna will do what? - ANSWER Travel indefinitely unless absorbed, reflected, or refracted. Radio energy always travels at what speed? - ANSWER 186,000 miles per second 30,000,000,000 centimeters per second The speed of light The frequency (cycles per second) of a radio signal changes when the signal is reflected from a target that is moving at a different speed than the RADAR device. This change or shift is known as? - ANSWER The "Doppler Shift." The greater the relative velocity, the greater the frequency shift. By measuring the degree of frequency shift, the RADAR is able to display the target-vehicle speed in miles per hour While the signal speed remains constant (speed of light), what other two characteristics of radio waves are variable? - ANSWER The wave length, and the frequency Wave Length - ANSWER The physical distance, or length, from the beginning of the peak to the end of the valley. Frequency - ANSWER The number of waves transmitted in one second of time Frequency is measured in what? - ANSWER Cycles per second. One cycle is the same thing as one wave. Scientists and engineers often use the term Hertz (Hz) instead of cycles per second. All of these terms have the same meaning: one Hertz equals one cycle per second, which equals one wave per second X-Band RADAR signal - ANSWER has a wave length of approx. 3 centimeters (1.1 inches) and a frequency of 10,525,000,000 waves per second, or 10.525 Gigahertz. K-Band RADAR signal - ANSWER has a wave length of about 1.25 centimeters (.49 inch) and a frequency of 24,150,000,000 waves per second, or 24.150 Gigahertz. Ka-Band RADAR signal - ANSWER has a wave length of about 4/5 centimeters (b/w .35 and .33 inches) and a frequency of approx. 34,700,000,000 waves per second, or 33.4-36 Gigahertz. Christian Johann Doppler - ANSWER an Austrian physicist, is credited with having discovered (around 1842) that relative motion causes a signal's frequency to change. He discovered this basic scientific principle by studying sound waves, but it was later found that the principle applies to all kinds of wave motions including light waves, waves on water, radio waves or any others. We refer to this scientific fact as the Doppler Principle If the relative motion is bringing the object and the RADAR closer together, - ANSWER the reflected signal will have a higher frequency than the transmitted signal If the relative motion is taking the object and the RADAR farther apart, - ANSWER the reflected signal will have a lower frequency than the transmitted frequency The Doppler Principle's key point to remember - ANSWER is that the frequency change only happens when there is relative motion between the RADAR and the solid object Relative motion will only occur when the solid object and the RADAR are not moving in the same direction, at the same speed. Relative motion will occur if: - ANSWER 1. The RADAR stands still and the object moves 2. The object stands still and the RADAR moves 3. If they are both moving, as long as they move at different speeds, or in different directions so that the distance between them changes The smaller the angle - ANSWER the closer to true speed the greater the angle - ANSWER the greater the angular effect (slower measurement) You want the antenna as close to straight ahead as possible. Do not use more than what degree of an angle when running RADAR? - ANSWER Do not use more than a 20 degree angle The angular effect is sometimes called - ANSWER the cosine effect The angular effect causes the stationary RADAR speed measurement to be lower than the object's true speed. This effect always works in who's advantage? - ANSWER It works to the motorist (suspect)'s advantage when the RADAR is operated in stationary mode When may a RADAR unit not "see" an object? - ANSWER Depending on the size, shape, speed, composition, and exact location of the object, its reflected signal may not be "seen" by the RADAR unit A RADAR beam will go on forever until: - ANSWER Either absorbed, reflected, or refracted. A beam whose angle is 11 degrees will be more 38 feet wide at what point down the road? - ANSWER 200 feet down the road A beam whose angle is 11 degrees will be more than 57 fete wide at what point down the road? - ANSWER 300 feet down the road