Molasses - but as I thought that that was partly to blame for the slipperiness, I checked with Devon County Council, and they definitely don't use that additive - they do 'pre-wet' the salt so it doesn't fly off the road, but otherwise it's just salt & grit. Of course, salt does attract and retain moisture, so then the treated roads remain damp and slippery longer than an untreated road (as long as it's not icy!) Extreme caution required: a friend ended up cracking his hip and shoulder in a very low-speed slip on one of these greasy roads, and was off the bike for the best part of twelve months. Be careful out there.Yes. Salt mixed with the sugary mix (can't remember the name) they use so it sticks, add a bit of damp, slippy. Had the rear end step out twice on me today, going in a straight line due to road surface !
I don't know what the weather's like where you are but it's cold and very humid down here - like a cold sweat - adding to the effect of the salt. Plus, with the north-easterly, it hasn't rained properly for some time. I just had a nasty slidy moment when a pedestriarse stepped out on me without looking.They're definitely greasy/slippery, it's just not the salt that's doing it .