Metro Travel News confirmed the closure in a statement on twitter at about 6.20pm on Tuesday, April 2.
It said: "#Leeds - RTC - Stanningley By-pass is closed westbound immediately after the exit ramp for Richardshaw Lane. @firstwestyorks Service X6 Diversion Bradford bound via Stanningley Road at Bramley Town End to Bradford Road at Dawsons Corner due to the closure of the by-pass."
First Bus issued this statement at about 6.30pm: "Service Update RTC - Stanningley By-pass is closed BOTHWAYS, immediately after the exit ramp for Richardshaw Lane."
Police confirmed that they received a call at about 5.30pm to a three-car crash on Stanningley By-pass.
It happened on the Bradford bound carriageway.
It involved a black VW, a silver Audi A4 and a white Ford.
Minor injuries have been reported.
One lane re-opened at 6.16pm.
A reporter at the scene saw major queues and slow-moving traffic on Bramley ring road.
They also said there were queues right up to Morrison's and that there were a couple of number 4 buses sat in the queues.
First bus confirmed the bypass was reopen bothways at 6.55pm.