Residents and traders in Port Talbot fear the closure of the junctions would lead to the town being 'cut off' from business.
Steve Redmore, manager of Aberafan Shopping Centre, said the closure would restrict people coming into the town, which is not needed in the current economic climate.
More top news
Fire crews have been responding to reports of flash flooding in Carmarthenshire. Some homes have been affected.
Medication designed for animals was taken from the building in Abertillery on Thursday night.
More than a thousand riders will be taking part in a series of events in and around the town.