Close the East tributory (both dirrections) of the roundabout. Place barriers in the right lane of the roundabout forcing traffice coming off the bridge in the right lane to turn right. Place a barrier in the Right lane of the roundabout forcing traffic heading North on Broadway to continue North.

Do this for a week while you have contractors monitoring traffic.

YOU WILL GET complaints about access to/from George street.

I'd suggest the George street near the theater be made 2 way during this trial.

Also.... Consider relocating the streetlight next to the police department 1 block further south.