A 24-year-old man is in critical condition after he suffered injuries in a south Lawrence car accident Sunday morning. Jason Callwell was transported by ambulance and helicopter to a Kansas City hospital following the wreck, said Lt. Kari Wempe of the Douglas County Sheriff's Office. Callwell was a passenger in the 1999 Grand Prix driven by Jonathan Shaver, 24, Kansas City, Kan. The accident is still under investigation, but Wempe said it occurred when the vehicle slammed into a tree outside the residence at 877 E. 1000 Road at about 4:50 a.m. Sunday. Shaver's injuries were minor and did not require immediate treatment.