[sustran] Stop engine at the intersections

[Roger Higman]

ITDP wrote:
> 
> This idea of stopping engines briefly to reduce air pollution is not a
> good idea.  While I don't have the figures, I'm pretty sure the
> emissions generated by stopping and starting the engine again are
> considerably greater than the emissions generated by hot idling.

Obwon followed with:


> Yes, I was struck by that point too.  I think it's been discussed here
> before... Does anyone know or remember what the 'breakpoint' is?  

My recollection is that the breakpoint is at about two minutes, but it 
is a long time since I've looked at the issue.

As the light-up time for catalysts gets shorter (ie: they begin to take 
effect more quickly) the breakpoint will fall. It may therefore be much 
lower than two minutes on a new car.

Roger Higman                                    "A thorn in the side of 
Senior Campaigner (Atmosphere and Transport)         the motor industry"
Friends of the Earth (E,W+NI),  	        	   Car Magazine
26-28 Underwood Street,
London, N1 7JQ
                                                       
Tel      + 44 171 566 1661                       Fax   + 44 171 490 0881
E-mail   rogerh at foe.co.uk                        http://www.foe.co.uk