The Journey Time data feed provides details on Journey Times , such as location, configuration and dynamic journey time updates.
The Journey Time data is split across 2 feeds:
- Journey Time Static
- Journey Time Dynamic
The journey time links listed in the API are managed by either:
- Tyne and Wear UTMC, these are prefixed “CAJT”;
- Highways Agency, these are prefixed “Section”; or
- Tyne Tunnel2, these are prefixed “TT2”.
The journey times are derived from Automatic Number Plate Recognition (ANPR) Cameras. These cameras read the Vehicle Registration Mark (VRM) and apply a non reversible algorithm to provide an anonymous Tag for each VRM. Should a Tag for a vehicle be detected at a camera downstream on the link in question, a travel time is then calculated. An average journey time is then worked out for the link using the matched tags for that period.
It should be noted that this data is not used for speed enforcement purposes and that operators in the UTMC centre have no access to any of the raw VRM data.
The provision of journey times from the HA and Tyne Tunnel 2 is beyond the control of Tyne and Wear UTMC and can at times be intermittent (especially for the two Tyne Tunnel 2 links). It should also be noted that ANPR systems rely on:
- A sufficient number of vehicles travelling between two cameras to be able to derive an average. Therefore if a road is closed due to an incident no journey time will be recorded. For links with the prefix CAJT if insufficient vehicles are making the journey (i.e. during the middle of the night) free flow speeds are returned.
- Being able to read the registration plates. Therefore in extreme weather conditions such as heavy snow, journey times may not be available.
More information on the content of these feeds can be found here.