Many, especially small firms, may try to go the long way round so as not to cross the boundary. Whatever happens it will be a huge, city-wide shock set to create a new network of rat runs.
Here's a helpful list of last-second turns for those determined to swerve the dreaded CAZ when it comes in on Monday, February 27.
Initially, it is forecast to catch about 2,000 drivers and rake in £23,000 every day, or £8.46m-a-year. These vehicles will be charged: 'polluting' heavy goods vehicles (HGVs), light goods vehicles (LGVs), vans, buses, coaches and taxis. Private cars and motorbikes will not be charged. The council was given £24m to help firms buy newer vehicles, or convert old ones to electric. Details here.
2. Ecclesall Road
Coming down Ecclesall Road, the last turn off before the CAZ on the inner ring road is William Street, a left turn into Broomhall. From there you could go Broomhall Road, Victoria Road, Collegiate Crescent, Park Lane, Clarkehouse Road and Glossop Road to get near the university roundabout at Brook Hill. Photo: .
3. The Parkway
Coming into Sheffield down the Parkway your last turn is into Parkway Central Retail Park. You can wriggle through the car park and get out on to Cricket Inn Rd. Photo: .
4. Clean Air Zone
The CAZ, which looks a bit like the Millennium Falcon, starts on Monday February 27. Photo: .