During the peak exit time it flushes the traffic out faster if they force everyone from the M&F Structure to go over the bridge and onto the I-5. Or to continue on up Manchester Ave.
Trust me, I flushed out the Devonshire Downs parking lots every July 4th for 20 years, and we had it down to a science. Pick one direction for the cars from each exit gate to take, get the exiting traffic their own lane or override the signals so they don't stop flowing out the lot.
Keep Them Moving, even if they aren't initially going the direction they want. If you can get people to keep moving out past the 'gridlock zone' they can make a circle-the-block U-turn and head for home without locking up everyone behind them.
We emptied out an entire college football stadium (with people seated in the stands and out on the field) that all want to leave at once in under an hour, the same kind of crowd DL deals with on a normal day.
If Disney offers a choice there, you always get the one person sitting there stopped right at the split point going "Which way do I go, George? Which way do I go?" which quickly locks up the whole exit driveway behind them. Ten seconds later the horns start honking, and another thirty seconds and people start jockeying to go around and find another exit, and you've lost the nice orderly exit plan. Anarchy and "To heck with everyone else, I've Got to Get Out First!" mentality sets in, and the guys with the Macho 4X4 will flatten the fence to make their own exit lane.
That leaves the Ball Road & Disneyland Drive intersection and signal free to handle the Downtown Disney and Hotel traffic, which it can do without backing up hopelessly. And if it does back up, they can always station an Anaheim PD Officer there to override the signal for a half-hour and flush them out.
Experiment626: Now that you know this will be SOP for a while, plan a route for it. Go north on Manchester, take the first left you can at either South St. or Santa Ana St., go east one block to Walnut St., and take Walnut south back to Ball Road.
--<< Bruce >>--