Gritting with rocksalt and molasses.
 

For the past few days I have been clearing snow (from the steep hill outside my house) and spreading 'grit' from the bins provided by the council.
I have become accustomed to the sweet smell before I realised that the rocksalt has had molasses added to it (I recalled the smell from silage).
This is done to assist the salt to stick to the road, rather than getting blown aside by passing vehicles. Once the salt has 'melted' it leaves a sticky treacle coating on the tarmac - which seem to be quite slippery when walking on it.

This is not intended to be any criticism of the practice of mixing molasses with rocksalt (potash), merely an observation.

The Idiots' Guide to Highways Maintenance