There are now 30 speed cameras on the road between Stonehaven and Dundee, and they are enforcing the average speed limits there.
Transport Minister Humza Yousaf said: "I have confidence that the average speed system, which is now operational on the 51.5-mile stretch of the A90 between Dundee and Stonehaven, will help save lives. The evidence from other average speed systems across Scotland continues to demonstrate the various benefits these cameras will bring to drivers."
Not everyone shares that view. Some regard it as a money making scheme, with £100 being charged on top of three penalty points. (A ban is imposed once you have totted up 12 points - or just 6 points for new drivers). The courts can impose much higher penalties for excessive speed and there are increasing moves to charge a percentage up to 150% of the offender's weekly income. But with so many drivers going just too fast, and so many deaths and serious injuries on this stretch of road it will be interesting to see what effect the new average speed cameras will have.