...when its frosty. Anyone know off the top of their heads recommended spreading rates are to prevent frost/ice forming on pavements? I know its in the BS but I don't have a copy to hand. I'm getting fed up with wading through drifts of rock salt and want to do a bit of re-education. I'm less interested in application rates to prevent snow accumulating or for melting fallen snow - its looking increasingly unlikely that thats going to be an issue this winter in London.

It doesn't work below -5

I'm intrigued that there is actually a recommended application rate/quantity. How can it actually be measured/checked in practice to anything like a reasonable estimate? Take your typical highways lorry grit/salt spreader - driving along at maybe 30mph, with the rotating spreader 'disc' at the rear. Presumably the driver drives as conditions permit, other traffic gets in the way (while the grit takes the paint off your car doors etc). Seems like a best guess to me. Likewise a typical manual application from a shovel, applied by 'swinging' the shovel to spread the salt,while picking up the salt from a wheel barrow etc. All seems to me salt/grit is laid in a reasonable manner - which is about the best you can say. Lets not forget of course, if freezing in London - the capital grinds to a halt with the slightest dip in the mercury...

The guidance document 'Well Maintained Highways' has the reasonable rates of spread for road salt, etc. These rates are tried and tested by TRL and National Road Research Group. Below -9 (road surface Temperature) the amount of salt required would be a danger to road users and have no added effect. Equipment used for spreading salt (not grit) are calibrated, as given in a previous post. Correlation between vehicle speed, spinner speed and grams per m2 is controlled by the on-board computer and the input of the operator/driver. The maximum spread rate is given as 40grams/m2. Other de-icers are available...