Travel Time Surveys

Involves the measurement of a vehicles time with respect to its distance travelled.

The survey technique can be as simple as a stop watch and recording time past known points of identification along a road network. However this simple technique does not with stand modern day accountability review.

The optimum method is to use a instrument or combination thereof.

Instrumented vehicles may entail the logging of vehicles tail shaft rotation via a hall effect sensor and the interfacing with a data logger or laptop PC.

The more flexible instrument is the deployment of GPS and inbuilt data logger, this device can be used more readily within a vehicle fleet or deployed in any road or water borne vehicle or bike or walker. GPS does have a few limitations, satellites can be overshadowed by tall buildings or tunnels and occasionally there are not enough active satellites within our hemisphere. However given the cost effectiveness of such a surveys data set, the tradeoffs are acceptable in most circumstances.

The penultimate system is a hybrid of both GPS and connection to the Vehicles Odometer system.

Travel time surveys can be applied to any vehicle private or public transport on road, water or air or persons in a vehicle or walking or riding a bike.

ATS has perfected the use of GPS and a suite of software for filtering out extraneous information and correcting for some outlier readings. The resolution of GPS is adequate for conventional node to node travel time surveys.

Special application of travel time surveys may involve public transport vehicles say buses or trams and the recording of their vehicle identification numbers coded with a site ID and time of passing, this data can be analysed to produce a travel time profile along the network for the study vehicles.