Speed cameras on a Midland stretch of motorway which is piloting a £100 million Active Traffic Management system have not been switched on yet, a Highways Agency spokes-woman said yesterday.
The "handful" of cameras set up as part of the high-tech surveillance scheme on the M42 may not be switched on when the pilot is finished, it was also confirmed.
The ATM scheme, which includes mandatory variable speed limits, is in place between junction 3a (M40) and 7 (M6).
The HA introduced lane speed limits on the road last November, and intends to use the hard shoulder as an extra lane for cars when congestion levels are particularly bad in the coming weeks.
The speed limits were originally thought to be enforced through the use of speed cameras.
However, a HA spokeswoman said yesterday: "There are only a handful of cameras at the stretch and they have not been switched on yet.
"This is a pilot scheme and they may not be switched on when the pilot is over. Obviously the mandatory speed
limits are monitored, but we do not yet know whether the cameras will be part of the scheme in the long term."
The speed limits are controlled from a new traffic control centre in Quinton, Birmingham, and displayed to drivers via the latest overhead gantry signs, spaced at intervals of just 500 metres along the 12 mile pilot stretch.
The scheme represented one-fifth the cost of widening the road, was quicker to introduce and should increase capacity on the stretch of motorway by up to 20 per cent, according to the HA.