Bourbon St. -- St. Ann

Bourbon St./St. Ann St.
When Ignatius and Ms. Reilly left the Night of Joy, they walked to her car, which was parked on St. Ann St., just off Bourbon St.

Mrs. Reilly had a difficult time extracting the 1946 Plymouth from the parallel parking space and hit a Volkswagen that was parked behind them. She also “climbed the curb twice” during her efforts, and Ignatius was of course no help as he complained endlessly from the back seat.
Finally, the car “leaped out of the parking spot and skidded across the wet street into a post supporting a wrought-iron balcony.” Toole described Mrs. Reilly and Ignatius hearing the “splintering of wood” as the balcony fell on the roof of the car.
Here’s a photo of the corner…

Notice the balconies on the left? The support posts that are painted white are the only wooden ones on the block. All the others are wrought-iron. It was probably those posts that Mrs. Reilly splintered.
In addition, parallel parking is on the right-hand side of the road. If Mrs. Reilly was going to skid across the street and hit the post, that would be the perfect place to do it.
Here’s a closer shot of the posts…

Just as Mrs. Reilly was smashing the posts, Patrolman Mancuso was walking down Chartres. He turned the corner, looked up St. Ann and saw “the green hunting cap emitting vomit among the ruins.”
Here’s a shot on St. Ann looking towards Chartres. It’s the next intersection…