LESSON 1/TASK 1
Recording
Figure 3 is an illustration of a completed speed study field sheet. These forms are produced locally and
can be adapted for special local requirements. Personnel assigned to conduct the speed study must
be made familiar with the sheets prior to recording data. These individuals must be fully briefed as to
what information is required and its importance.
The field data sheet has two speed columns. Each of them represents a determination of the speed a
vehicle traveled over a given distance. In using time measuring devices, two distances are often used.
Figure 3 uses distances of 88 feet and 176 feet. The speeds in the columns represent the speed a
vehicle traveling that distance, in a given amount of time, would be traveling. For example, if the
vehicle covered 88 feet in 1 second, it was traveling at 60mph. If it covered 176 feet in 1 second, it was
traveling at 120mph.
Timing Equipment
There are several types of equipment that may be used in conducting speed studies. Equipment is
constantly being improved and updated. However, the best available equipment should be used. The
more accurate the equipment, the more accurate the data will be. The best equipment available will
only be as accurate as the individuals operating it. When selecting personnel to conduct speed studies,
you must ensure that they are fully trained to operate whatever device is to be used. Some of the more
common equipment includes:
Radar. Radar equipment provides highly accurate readings of speed. Several types of this equipment
are available. It can be used during both day and night operations. When used, however, it must be
placed so that it is not readily seen by motorists. Their being able to see it, and/or getting word that it is
there ahead of time, will cause them to deviate from their normal driving habits.
Electric Timers. An electric timer is highly accurate in determining speed. It is an electric stopwatch
device. The stopwatches are activated and deactivated by vehicles passing over air tubes stretched
across the road. These have the advantage that motorists are familiar with a similar device that counts
the number of vehicles and are more likely to follow normal driving habits.
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