This is done using pre-determined agreed primary and secondary gritting routes.
These routes cover all the main roads (except the carriageways and footways of Red Routes ... gritted by Transport for London), shopping centres, roads with steep gradients and bus routes.

Footways are not routinely treated.
However the Council treats footways for gritting according to a priority system, including those in major town centres and local shopping centres, footways close to heavily used areas, such as schools, railway stations, hospitals and medical centres, footways designated as "safe route to school" and other locations with specific access problems. Our footway gritting operatives do sometimes leave piles of grit on the footway for their own future use.