Wiltshire Council's scheme is to go live on 21 October.
"People Friendly Salisbury is an exciting and ambitious project to prioritise walking and cycling in the centre of Salisbury. It will see pedestrians and cyclists given priority, as several streets in the city centre will be restricted for use by through traffic."
Source - Wiltshire Council.
Note that if you wish to drive into Salisbury to visit friends' homes, you will need to apply for a free permit to access the zone.