A crash involving a jackknifed tractor-trailer slowed traffic along Interstate 45 near Illinois Avenue in South Dallas Tuesday afternoon.
The truck appeared to have been traveling northbound and crossed the grassy median before it came to a stop in the oncoming, southbound lanes.
Several other vehicles, which appear to be involved, came to a stop far off the road in grassy areas.
Deputies with the Dallas County Sheriff's Office were at the scene awaiting Dallas police who had not yet arrived at the crash; Dallas police work crashes on I-45 and not the sheriff's office.
On the southbound side, drivers passed by the crash on the shoulder. On the northbound side, drivers were able to pass the crash in the right two lanes.
At 3 p.m., traffic southbound was backed up about eight miles toward downtown.
The cause of the crash is not yet known.