Intersection Turning Movement Counts
Turning movement counts are an important input to intersection analysis and to support development applications.
TAPS is equipped to undertake these types of surveys to ensure the collection of accurate and reliable data. Typically intersection turning movement surveys are undertaken by field staff using manual clickerboards. The survey staff is then required to manually enter generally 15 minute totals throughout the survey period. At a busy site this can easily cause the surveyors to become overloaded leading to errors in the recording and timing of recording and frequently vehicles are missed or double counted.
To overcome these deficiencies in traffic surveys we undertake suervys by a number of means aimed at reducing the load on filed staff and improving the accuracy of the results produced.
Techniques used for observational studies include:
- Use of automated data boards for counting; and
- Miovision Video System.
Automated Databoards
TAPS uses databoards supplied by Jamar Technologies. The databoards can collect up to 12 movements at an intersection with the capability of allowing storage for up to 3 classes of vehicles and pedestrian movements stored separately. The boards allow a surveyor to record an observed vehicle simply by pushing a button on the board. The board automatically stores the running totals of the survey at either 1, 2, 5, 15, or 60 minute intervals. Generally for intersection turning movement surveys a 15 minute interval is selected.
Whilst it is theoretically possible for one surveyor to undertake this type of survey at an intersection we have found that it is preferable to have two surveyors on most intersections and at very busy large intersections up to four surveyors are used to ensure an accurate survey result is produced.
Miovision Video System
TAPS can also provide a service where turning movement counts can be provided by an automated video collections system. In this type of survey the overall intersection operation is recorded using a proprietary video recording system. The video is then uploaded to the Miovision site in Canada where the video is processed in one hour increments and the results of the analysis then downloaded for formatting and delivery to the client.
This system allows classification of vehicles observed into Light, Medium and Heavy Vehicles and can also, if required separate Buses, Pedestrian and Cyclist movements.
There will be a number of issues that need to be considered in designing a turning movement survey and selecting the best technique to undertake the survey. Consequently clients should discuss their requirements with our experienced staff to ensure that any surveys undertaken are designed to provide the outcomes desired.
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