Truvelo cameras are siilar to Gatso cameras, in that they are permanently installed next to the carriageway. However, unlike Gatso cameras, they can be rotated to take photographs of either the front or the rear of a vehicle. A magenta filter is applied to the flash to prevent oncoming drivers from being dazzled. Truvelo camera housings are painted yellow to make them visible to motorists from a distance.

In front facing mode, Truvelo cameras work as follows:

• Sensors in the road record the time at which the vehicle crosses them.
• The time difference between sensors 1 and 3, and between sensors 2 and 4, is calculated. These measurements are used to calculate the speed of the vehicle.
• If the vehicle's speed is above the preset threshold (eg.30mph) then a photo is taken.
• There are three white lines painted on the road surface. The photo is taken when the vehicle crosses the middle white line. The other two white lines are set at +/- 10%. This is the legal required accuray.

In rear facing mode, Truvelo cameras work as follows:

• Sensors in the road record the time at which the vehicle crosses them.
• The time difference between sensors 1 and 3, and between sensors 2 and 4, is calculated. These measurements are used to calculate the speed of the vehicle.
• If the vehicles's speed is above a preset threshold (eg. 30mph) then two photographs are taken.
• These photographs show the vehicle's position in relation to the check marks on the road.

Truvelo cameras are less common than Gatso cameras in Greater Manchester, but are used in locations where front facing cameras are more suitable.

The cameras themselves are rotated among the housings, allowing us to target resources where they are most needed and provide best coverage of the road network. It is safest to assume that any camera can be live at any time.

The Police have discretion to undertake speed enforcement anywhere within the Greater Manchester area, activity which is separate to and not funded by or through the Partnership, and not subject to the Partnership's protocols nor scrunity of the Partnership Board.

Compliance with these protocols and procedures has no bearing upon enforcement of offences detected by the use of the safety cameras, and non-compliance with them by the Partnership or representative of the Partnership does not provide any mtigation or nor defence for an alleged offence committed under current UK law.