I loved this video from Break.com
I'm told such a feature will appear in Málaga shortly. There was some discussion on ADUK about the safety aspects. My personal variation would be to have the bollards at entrance and exit to the zone and a feature which trys to avoid hitting cars that 'run' the barriers. The car is then simply trapped in the zone and cannot escape until the fine is paid - probably involving a long walk to the police station.