Last night, firefighters were called out after a car was set alight in Grove Road, Staincross, Barnsley.
At 6.40am on Saturday, firefighters were called to Fullerton Road, Canklow, Rotherham, after a lorry was set alight.
Earlier that morning a Volkswagen Boro was torched in Hickleton Road, Hickleton, Doncaster.
Anyone with information should call South Yorkshire Police on 101.