A traffic control devices study can insure that the devices are adequate and placed where needed. Such studies are performed initially on an installation and then periodically. This periodic checking may be weekly or monthly, based on checking specified geographic areas or simply through using patrol reports on a daily basis.
There are three types of control devices that may be studied separately or in combination:
Used to regulate, warn or guide traffic. These are studied to:
Used to regulate, warn or guide traffic. The purpose of these power-operated devices is the same as for signs.
Used to regulate, warn or guide. These are the lines, patterns, words and other devices set into pavement or curbing. They are all studied for the same reasons.
Two-person teams, on foot or in vehicles, are used to conduct traffic control devices studies. An orderly system of travel should be organized for them and other teams used in each study. The study may be organized into day and night operations to compare differences. Special equipment should include:
- Manual on traffic control devices.
- Tape measure (100 foot).
- Field sheets for collecting data (samples below).
Things to be checked on signs are:
- Type (stop, yield, right curve, etc.).
- Size and Shape.
- Reflectorized or not (how).
- Location of Sign (street, distance from pavement or curb, distance from intersection, height).
- Visibility (size, location, lettering and maintenance).
Phasing of signals is checked through several cycles with the stopwatch. It's helpful to make sketches of signals to understand the timing, phasing and sequence of signals. They are checked for:
- Type (fixed time, flashing, full traffic actuated).
- Location and position. Physical Information (size, color, number of lights).
- Timing of Each Phase (green, red and amber time).
- Phasing (time the light is applicable to each direction at an intersection. For example, green on Main Street for 45 seconds, and green on the intersecting street for 30 seconds.).
Pavement Markings Study
Use the odometer of the vehicle to measure length of lines. Markings are checked for:
- Visibility (condition and reflectiveness).
- Type (solid, double lines, left turn lanes, etc.).
- Material used (paint, glass, etc.).
- Measurements (line length and width).
Information and data collected in this study may be recorded manually in a card file loose-leaf notebook, or through machine processing (ADP) using standard 80-column punch cards. Records of the study should be maintained in the traffic section of the provost marshal office.
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