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Chapter 6

Traffic Law

Principles and Policies

A traffic violation or offense is broadly defined as the commission or omission of any act prohibited or required by rules, regulations or laws governing the conduct of traffic. The purpose of traffic law enforcement is to make the roads safe for all traffic and to encourage voluntary compliance with traffic laws by all motorists.

Well-defined policies concerning enforcement of traffic laws must be established by the installation commander. Since the Military Police will often be required to make on-the-spot decisions, they should keep in mind these policies and principles:

  • Take uniform action for the same violations under similar conditions.
  • MPs should be able to detect and identify unusual or illegal behavior, or conditions which produce or accompany such behavior.

    MPs should be able to evaluate the legality or illegality of such behavior and interpret its effect on applicable laws.

    MPs should be able to apply allowable tolerances and know if they have sufficient evidence to support the formal citation of an offense.

    MPs should be able to apprehend violators under adverse conditions.

  • Take immediate action once a violation is observed. This must be done with the safety of the public and the MPs in mind.
  • Selective enforcement is the distribution of MP traffic control assets where they are most needed and will be most effective. It is based on the prediction and prevention of future violations and accidents from past experience. Patrols are assigned duties in proportion to violation and traffic accident distribution by time and place. Efforts are directed to reducing violations and accidents by the presence and activity of MP patrols.
  • When establishing guidance policies for MPs, tolerances are often implemented. This leeway allows for mechanical and human error.
  • For example, if the speed limit is 30 mph (48 km/h) policy might be that speeding violations will be cited only when speeders exceed 35 mph (56 km/h). Tolerances strengthen any enforcement program since it prohibits the excuse that a mistake has been made.

    CAUTION: Do not allow tolerances to be arbitrarily increased.

  • The community should be informed when certain driving actions are causing accidents or traffic problems. The community should also be informed that stringent enforcement efforts are in effect. This will enhance the enforcement effort.
  • Speed Measuring Devices

    While speeding does not cause all accidents, it does have a definite effect on the severity of accidents. For this reason, efforts to control speeding are often of prime concern. Speed measuring devices are used to control speed, increase compliance with traffic laws, and to conduct speed studies.

    When planning for use of speed measuring devices, the following considerations must be evaluated to determine the device or method most suited for any given situation:

  • Cost.
  • Local recognition by judicial authorities.
  • Training required for persons to use devices.
  • Maintenance requirements.
  • Mission and environment of unit employing the devices.
  • Pace Method

    In this method, the MP driver positions his vehicle behind the suspect vehicle and matches the driving speed. A constant interval should be maintained between the two vehicles for a minimum distance of 3/10th mile (.48 km). The MP should note the speed when this process first begins, and again when the distance is completed.

    To employ this method the MP vehicle must be calibrated to insure that its speedometer gives a true indication of speed. Only the driver should note the speed since he is looking directly at the speedometer. The MP rider will get a false reading due to his angle of sight.

    The driver should read the speedometer after his catch up speed has stabilized and is the same as the suspect vehicle. The matching speed must be maintained, and the driver should call out the speedometer readings to the partner during the pace.

    Speedometers should be calibrated at least quarterly. A chart must be maintained in each patrol vehicle listing any speedometer deviation from true speeds up to the top speed at which excessive speed arrests can be expected. Speedometer more than 2 or 3 mph (4 or 5 km/h) off should be repaired.

    Time/Distance/Speed Computations

    Once distance has been accurately measured, precise timing of the period necessary for a vehicle to travel such distances permits computation of the vehicle's speed.


    A stopwatch can be used to determine the speed of vehicle traveling a measured distance (normally 1/6 of a mile, 880 feet or 265 meters). Tables which relate miles per hour to the elapsed time necessary for a vehicle to have passed through the distance being used, enable an MP to determine the speed of any vehicle he times.

    Aircraft Enforcement

    Speed enforcement by this method is used by air and ground teams. The MP in the aircraft determines vehicle speed and relates the identity, speed, location and direction of travel to the ground unit which effects the enforcement contact.

    Painted marks on the roadway at precisely measured intervals (from 1/8 mile to one mile) are used by the MP in the aircraft to mark the beginning of the speed measuring course.

    Airplane silhouettes may be used as the painted marks to increase the sense of presence of traffic enforcement personnel.

    Automatic Stationary Speed Computer And Recording Instrument (ASCRI)

    This type device is placed adjacent to a road or highway and consists of four main parts:

    Sensing devices in the roadway which detect passing vehicles between two precisely messured points.

    A computer which automatically produces a speed figure from the information received from the sensing devices.

    A light source which provides light sufficient for photographing the vehicle and its operator without interfering with the driver's vision.

    A camera which photographs simultaneously on one frame the vehicle and driver, the speed figure produced by the computer, the time, date, location and any other information essential for prosecution and previously set as a display within the instrument.

    The ASCRI is set to record only those violators exceeding the speed limit by a sufficient margin to require enforcement action. If driving too slowly is a problem, the instrument can be set to record this type of violation also.

    Personnel are required to replenish the film supply; develop the film; and process notifications to owners of the involved vehicles of the enforcement action contemplated. An accurate installation vehicle registration system and coordination with the state, or other applicable vehicle registration agencies is necessary for efficient processing of violations.

    Installation of the ASCRI is recommended primarily at the beginning of reduced speed zones, such as entrances to an installation, troop area, school zones, etc.


    RADAR (radio detection and ranging) speed measuring devices operate by measuring the difference between high frequency radio signals sent from the instrument and the signals reflected back to the instrument by the object vehicle. The instrument automatically reads out the difference in miles per hour (km/h). A desirable characteristic is automatic or self-calibrating.

    The three basic types of RADAR devices used by MPs are stationary, moving/pacing, and handheld.

    Stationary RADAR

    This type device is normally operated from a patrol vehicle parked along a roadway for stationary observation and enforcement. An additional patrol vehicle is stationed to intercept vehicles identified as speeding by the RADAR-equipped patrol.

    Desirable model characteristics for stationary RADAR include digital readout with speed lock-in capability, audible alarm and range selector. The antenna should have an all-weather housing and brackets for window mounting.

    Moving RADAR

    This type device installed in a patrol vehicle (normally connected to the cigarette lighter receptacle) allows the patrol to selectively monitor speeds of approaching devices up to approximately 2,500 feet away while the patrol vehicle is moving.

    The mobility of moving RADAR-equipped patrol vehicles allows high visibility of MP patrols, which is an important deterrent to speeders.

    RADAR models selected for use should have the following characteristics:

    Audible alarm--triggers when a speeder is detected, thus eliminating the need to constantly watch the readout unit.

    Easy-to-read digital display--also locks the violator's speed for reference by the MP and the violator after the enforcement contact has been made.

    Portable operation--with addition of a battery pack.

    Solid State Circuitry

    Capable of stationary mode operation--when patrol vehicle is conducting stationary enforcement.

    Range selection capability--to extend or reduce operational range, depending on terrain or structured influences.

    Hand-held RADAR

    These small, lightweight devices have a completely enclosed component antenna and are powered by either a cigarette lighter receptacle or a portable battery pack.

    Commonly known as speedguns, a hand-held radar, after being turned on, continuously emits a microwave signal which bounces off the vehicle and is absorbed by the shield in front of the speedgun. This is instantly translated into a digital readout on the screen of the speedgun and can be locked in by pulling the trigger. This allows the reading to be held on the screen until the release button is pushed.

    Desirable model characteristics of speedguns include:

    Easy-to-read digital display.

    Solid-state circuitry.

    Telescopically coiled, retractable power cord.

    Can be vehicle mounted.

    Hand-held RADARS used by MPs on motorcycles can be easily stored in attached saddlebags or accompanying cart.


    Operator Training--Operators require minimum training in site selection, positioning and handling of antenna, use of internal calibration system or tuning fork, judging effects of terrain and structural influences, and severe weather conditions such as heavy rain.

    Maintenance--A scheduled maintenance program in accordance with manufacturer specifications must be established and re cords maintained of services performed by qualified technicians.

    Tuning Forks--The tuning fork is a calibrated instrument certified by the manufacturer. It should never be struck against a hard object. Preferably, strike the heel or sole of your shoe.

    Civil Laws--Supervisors must insure compliance with applicable civil laws. Since radar operation can interfere with other communications, some jurisdictions require prior approval for its use.

    Drunk Driving

    The operation, while drunk, of any motor vehicle is punishable under Article 111, Uniform Code of Military Justice. Law enforcement personnel normally detect this violation by observation of unusual, abnormal or illegal driver behavior. Some examples of these types of behavior are:

    Driving with extreme caution, especially slow speed on through streets and highways; stopping where no stop is required; long stops at stop signs; and apparent confusion at intersections.

    Lane straddling, speeding, or failure to signal a turn.

    Erratic movement, such as weaving; driving in the wrong lane; driving on the road shoulder and moving over the center line, especially on curves.

    Swerving farther than necessary when passing or taking a long time to return to the proper lane after passing.

    Failure to dim bright lights and/or repeated difficulty in engaging gears of a vehicle.

    Investigative Procedures

    When a traffic accident or violation occurs and law enforcement personnel observe unusual, abnormal or illegal driver behavior indicating driving ability might be impaired due to alcohol or drug use, observation and behavior tests should be made and recorded on DD Form 1920 (Alcoholic Influence Report). Driver actions such as reaching for license or getting out of the car can be very valuable evidence.

    MPs should also obtain as much information as possible concerning the incident during the investigative phase.

    Areas to be investigated:

    When, where and with whom did the suspect drink?

    How much and what type of liquor was consumed?

    What conditions were involved in the accident, and/or how did the suspect operate the vehicle?

    Are there physical or emotional conditions which might explain the suspect's unusual behavior or apparent intoxication?

    Is there paraphernalia, associated with intoxicants, on the suspect's person or vehicle?

    Frequently a suspect will exhibit one or more signs of alcohol or drug influence such as odor of liquor, slurred speech, profanity, sloppy appearance, unsteadiness or irrational behavior. It should be noted that any of these signs may also be caused by chronic or acute illness or physiological conditions such as diabetes, amnesia, shock, nervousness, speech disorders, muscular dystrophy, etc. If illness is suspected, medical authorities should be contacted immediately.

    After you decide that a driver is under the influence of intoxicant or drugs, never allow the person to operate his vehicle. You must secure his personal property and vehicle. Before driving or towing a privately owned vehicle, you must obtain the consent of the driver/owner. There should be an impound location near the MP station to park such vehicles.

    Logic Tree for Processing Drunk Driving Suspects

    Editor's note: This graphic is not viewable in HTML format. Check "Download Document" at the top of this file for an alternate format or obtain a printed copy of the document.

    If the driver/owner refuses to let you or another person drive the vehicle, secure it at the scene by locking the doors and removing the keys.

    DD Form 1920

    DD Form 1920 is used to record observations and behavior tests conducted on persons suspected of driving under the influence of alcohol/drugs. The form consists of a heading and six sections. The order in which these sections are filled out is based on local policy which will also include when to offer chemical testing of blood alcohol levels.

    Blood alcohol concentration standards are established for administrative and enforcement purposes in AR 190-5. The following standards maybe modified depending on the policies of the state or country:

    0.0% to 0.05%--not intoxicated

    0.05% to less than 0.10%--not necessarily intoxicated; other evidence necessary.

    0.10% or greater-intoxicated

    Completion Steps for 1920


    Entries are self-explanatory in this part of DD Form 1920. Make no entry in blocks if the information is unknown.

    Section I--Observations

    Identify individual in the "Made By" and "Witnessed By" blocks. Include units and installation for each. Enter short descriptions as appropriate. In the "Clothes" block, mark out the inappropriate words. In each category, more than one block may be checked if applicable.

    Section II--Performance Tests

    Prior to conducting the tests in this section, a military suspect must be advised of his rights. The suspect may refuse to perform these tests; if so, enter "Refused Test." The suspect may also refuse to finish a test once started; if so, enter "Refused to Continue Tests." If a suspect refuses to be tested, move to Section IV (skip Section III).

    Conduct the tests as follows:

    Balance--Ask the suspect to stand upright, arms outstretched, on one foot. Repeat the process on the other foot. Observe his actions. Next have the suspect stand upright, feet together, eyes closed with his head tilted backwards. Observe and record his actions on the form.

    Walking and Turning--Have the suspect walk about 15 feet (4 to 5 meters) by placing heel to toe. Next sharply request the suspect to "turn around, please, and walk back in the other direction." Observe and record his actions.

    Finger To Nose--Have the suspect stand erect with eyes closed and arms extended horizontally. Instruct the suspect to touch his nose, first with his right, and next with his left index finger. Observe and record his actions.

    Coins--Place three or four coins on the floor and ask the suspect to pick them up. Observe and record his actions.

    Section III--Interview

    Prior to completing this section, every suspect (civilian and military) must be warned of his rights again. If the suspect refuses to answer, this section is not used. If the suspect does answer but the question does not apply, enter "NA." Read the suspect his rights again, prior to taking the handwriting sample of signature.

    Section IV--Chemical Test Data

    Under the implied consent policy outlined in AR 190-5, any person who operates a motor vehicle on a military installation is deemed to have given consent to a chemical test or tests of his blood, breath or urine for the purpose of determining the alcoholic content of that person's blood.

    When such tests are used, the MP will warn the suspect that under the implied consent policy, failure to submit or to complete a chemical test will result in a 6-month revocation of installation driving privileges. Suspects will be advised that they do not have the right to have a lawyer present prior to taking these tests.

    If the suspect refuses to be tested or fails to complete a test, the MP will complete a sworn statement stating why the MP had reasonable cause to believe the suspect was driving a vehicle while under the influence, and that the suspect refused or failed to complete a chemical test. This is then forwarded to the installation commander or his designee for action. Charges of driving under the influence may still be brought against the suspect based on other evidence.

    Chemical tests of blood, urine or other body fluids will be conducted by qualified medical personnel or by designated authorities of the state. Samples of blood and urine forwarded for chemical analysis will have a chain of custody established.

    Chemical breath tests are conducted by qualified personnel as outlined in AR 190-5. The type test used must be approved for use by the state in which the installation is located. The test must also be conducted in the way the state approves. In the absence of specific state guidance, the following procedures will apply:

    Observe the suspect for 20 minutes, during which he should not ingest alcohol, other fluids, foods or smoke.

    Verify calibration of the test instrument by using a control sample immediately prior to the test.

    Follow operating procedures in the manufacturer's instruction manual.

    Section V--Recording

    Complete this section if videotape, motion pictures or voice recordings are conducted. It is not necessary to warn the suspect of his rights if this is conducted in a manner in which the suspect can normally understand, given normal perception. It must not be done secretly.

    If any questions are to be asked or answered, the suspect must receive a rights warning.

    Section VI--Supplementary Data

    This section is for information concerning other witnesses, vehicle occupants, etc. It does not include descriptions of law enforcement personnel.

    In the "condition" block, enter a phrase which best describes the individual ("sober," "intoxicated," or "unknown.")

    Miscellaneous Violations

    In handling other types of traffic violations, you must exercise a high degree of judgment. These types of violations include:

    Stop Sign Violation

    Maintaining Improper Distance

    Time Limit Parking

    Improper Lane Usage

    Improper Parking

    Improper Turns


    Oversize or Overweight Vehicles

    Improper Backing

    Obstructing Driver's View

    Bicycle Violations

    Driving Too Slow (so as to interfere with the safe flow of traffic)

    When making judgment decisions, Military Police should always favor or give the benefit of the doubt to motorists.

    Whether a creeping stop, rolling through a stop sign, or weaving between lanes is dangerous or hazardous, must be determined by the MP, based on the situation and guidance received from the provost marshal.

    A method of checking parking violations is to chalk the tire and pavement in time limit zones, and then recheck after the given time. A leeway of 15 to 30 minutes should be allowed.

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