Diesels run so lean at idle that stopping is unnecessary, and also, starting and stopping reduces catalyst efficiency, as the honeycomb cools and then needs to re-heat (I refer to gas engines here).

Shell diesel in BC is already at 50 PPM and will be down to 15 (the new standard) in about 3 months' time.

2008 Mercedes-Benz B 200
2005 smart fortwo cdi pulse cabriolet
1966 Peugeot 404 Coupé Injection
1989 Peugeot 405 DL