Emergency services have been called to a multi-vehicle crash along the A1(M) in Doncaster.
Highways England said the crash happened on the northbound carriageway between J36 Warmsworth and J37 Marr.
Delays are building along the carriageway and around Doncaster close to the junction.
A Highways England spokesman tweeted: "A1(M) in South Yorkshire between J36 Warmsworth and J37 Marr - We have an road traffic collision involving several cars and an LGV.
"Traffic Officers and SYP Operations are en route. Traffic is building in the area. Doncaster traffic may increase around town."