The traffic management plan is likely to cost hundreds of thousands of dollars.
Tension between Metro and Washington baseball fans reached peak-vitriol on Thursday night.
During a 24-hour period, officials anticipate as many as 10,000 vehicles traveling to MGM.
As many as 160 county police officers could be deployed to manage traffic associated with the casino opening.
Metro trains are single-tracking between Smithsonian and Federal Center SW.
Officials said delays are resolved.
Metro officials want to open the system at 4 a.m. Jan. 20 and charge peak fares from 4 a.m. to 9 p.m.
The crash occurred near Muncaster Mill Road, which is closed to traffic between Route 124 and Shady Grove Road as police continue to investigate the scene.
The parkway is shut down between the Memorial Bridge and Route 123, authorities said.
The work— from road widening to adding new signage and a new interstate access — aims to help mitigate some of the traffic generated by the gaming resort