A valid blue badge must be clearly displayed at all times.
Once the cameras are in place the speed will resort to the national limit of 70mph.
Expect delays on the Sheppey Crossing this week as average speed cameras are installed.
Work began this morning and is scheduled to last all week.
Work was due to begin at 9.30am today and is scheduled to finish at 4pm next Monday, March 20.
Contractors are hoping to complete the £350,000 scheme by the end of the week.
The 63-year-old, of The Broadway, Maidstone, told police he had followed the vehicle because he suspected the crew was simply “popping home” and not to the scene of an emergency.