Delays of up to 11 minutes are currently being reported on the westbound carriageway between junction 32 for Pontefract and junction 29 for Lofthouse.
Average speeds of just 20mph are being reported.
Highways Yorkshire tweeted to warn drivers, saying: "#M62 Westbound between #J30 and #J29 - we are in the process of clearing an RTC to the hardshoulder.
"However there are considerable delays on approach.
"Please find an alternative route if possible."