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Travel time data using active test vehicles in combination with varying levels
of instrumentation: manual (clipboard and stopwatch), an electronic distance
measuring instrument (DMI), or a global positioning system (GPS) receiver.
It involves the use of data collection vehicle within which an observer records
cumulative travel time at predefined checkpoints along a travel route.
Then this information converted to travel time, speed, and delay for each
segment along the survey route.
There are several different methods for performing this type of data collection,
depending upon the instrumentation used in the vehicle.
These vehicles are instrumented and then sent into the field for travel time
data collection, they are sometimes referred to as ``active'' test vehicles
[16].
Advantages
- Advanced test vehicle techniques (e.g., DMI or GPS use) result in detailed
data.
- Low initial cost.
Disadvantages
- Sources of possible error from either human or electric sources that
require adequate quality control,
- Data storage difficulties.
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