Norwich residents react to the proposals.
Graham England, Acle, 73.
'It seems pretty fair to me from two points of view.
'You save your fuel and obviously help pollution, eventually at least.'
Jody Watts, Dereham, 22.
'I think it's a good idea, as it will discourage people from causing pollution.'
Robert Wilkin, Norwich, 77.
'I don't agree. They've got emissions down as low as they can.
'They would do far better to look at old buses that are on the road, and old lorries.'
Nick George, Norwich, 19.
'The cost in enforcing it would probably be better used to go towards other things like recycling.
'So I think it's a good idea in theory but cost-wise it's not going to be efficient.'
Gian Darsacchi, Dereham, 44.
'I think it's a good idea but I lived in the centre a couple of years ago and I honestly I don't think there's a pollution problem.'
Kevin Barber, Little Plumstead, 64.
'They've made such a bad job of the traffic management in Norwich.
'If traffic was moving faster and the engines were working better you'd get less pollution.'
Paige Cannell, Sprowston.
'I've been guilty of leaving my engine running for a few minutes or so when I'm out driving, but if it's any longer I'll turn it off.'
James Moon, Sprowston, 25.
'It is just common sense. 'If people are leaving their engines on for at least five minutes then it's not sensible.'
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