o Each station needs two means of communication to notify the supervisor of problems or
emergencies. One of the two should be a telephone.
o Valuable tools for analyzing traffic studies include photographic and video techniques. Still,
aerial, and motion pictures are effective in showing before and after views.
c. The purpose of making a traffic study is to find the answers to problems. When you analyze the
results you must guard against oversimplifying or looking for an easy answer. One of the most
common mistakes is not evaluating or exploring all the available information. When evaluating the
data, take into account the following factors:
o Long-term trends may not be affected by short-term changes.
o Fluctuations in a long-term trend may be caused by the economy or by short-term changes.
o Seasonal changes affect the volume and speed of traffic and the number and types of
accidents during certain times of day or certain months.
o Chance variations may cause misinterpretations during short studies.
Do not make the following mistakes in reasoning when analyzing data:
o Do not make unjustified assumptions concerning cause and effect. Just because A follows B
does not mean B caused A.
o Do not make generalizations based on averages. Averages are useful in stating typical
cases. For instance, icy roads may cause only 2 percent of total accidents in a year, but on icy days
they cause 100 percent.
o Do not use false accuracy. When averaging two figures and one is accurate and one is not,
results will be inaccurate.
d. Traffic studies are used to ensure the installation traffic control plan is adequate. It must provide
for the safe and efficient movement of traffic. Traffic movement is a consideration in the installation's
e. These studies are also used to plan selective enforcement techniques. As we discussed in
Lesson 1, this means placing enforcement personnel where they are most needed. You may be
responsible for supervising the preparation of traffic studies. Types of traffic studies include:
Observance of traffic signals.
Motor vehicle volume.