TRANSPO PRE-FINAL
Permanent Counters
Are used when long-term counts are to
be conducted.
Videotape/CCTV
-Observers can record count data by videotaping traffic.
-Traffic volumes can be counted by viewing videotapes recorded with a camera at a collection site.
-A digital clock in the video image can prove useful in noting time intervals.
Portable Counter
serve the same purpose as manual counts but with automatic counting equipment. Pneumatic road tubes are used to conduct this method of automatic counts.
Automatic counts
are usually taken in 1-hour intervals for each 24-hour period. The counts may extend for a week, month, or year.
ELECTRONIC COUNTING BOARDS
- Are battery-operated, handheld devices used in collecting traffic count data.
- Are similar to mechanical counting boards, but with some
important differences.
MECHANICAL COUNTING BOARDS
consist of counters mounted on a board that record each direction of travel.
TALLY SHEETS
Recording data onto the tally sheets is the simplest means of conducting manual counts. The data can be recorded with a tick mark on a preprepared field form. A watch or stopwatch is necessary to count the desired interval.
MANUAL COUNT RECORDING METHODS
(1) tally sheets,
(2) mechanical counting boards, or
(3) electronic counting boards.
Stopwatch
Is necessary to measure the desired count
interval.
tally sheets
Is the simplest means of conducting manual counts.
Traffic volume
- is defined as the number of vehicles (or persons) that pass a point on a transportation facility during a specified time period, which is usually one hour.
Queuing Models
Are derived from the assumptions regarding the vehicle arrival rate, departure rate and the number of departure channels.
D/D/1
Regular arrival, services rate and departure.
M/D/1
Arrivals of vehicles follow a probability distribution characterized by randomness. Departure is assumed to be regular.
M/M/1
Arrivals and Departure of vehicles follow a probability distribution characterized by randomness.
M/M/N
Arrivals and Departure of vehicles follow a probability distribution characterized by randomness and there is multiple departure channels.
Queuing Models
Are derived from the assumptions regarding the vehicle arrival rate, departure rate and the number of departure channels.