A broken down lorry is currently blocking part of the main route from Derry to Strabane.
Police have confirmed that the lorry broke down in the vicinity of Victoria Road in the Waterside area.
Motorists have reported tailbacks with traffic backed up to Craigavon Bridge in Derry.
Drivers have also reported long delays in trying to get through the area.
It is understood PSNI officers at the scene re-directing traffic at present.