TULSA, Oklahoma - The OHP is investigating two motorcycle crashes that resulted in serious injuries Saturday night. 

Troopers say the crashes happened on the I-244 westbound ramp to US 75 northbound in the northeast corner of the IDL around 7:45 p.m.

Reports say 43-year-old Justin Chitwood of Avant departed the road and struck the barrier wall, throwing him from his motorcycle about 75 feet. He was taken to St. John Hospital in critical condition.

Reports say 52-year-old David Brackett of Skiatook, who was on a separate motorcycle, also departed the road and struck the barrier wall. He was taken to the hospital in what the OHP called stable condition.

Neither of the drivers was wearing a helmet, troopers say. 

The cause of the two crashes is still under investigation. Troopers are asking any witnesses to contact the Oklahoma Highway Patrol's Tulsa office.