Whilst I am not someone who does traffic management for a job, for a start I'd ensure a clear run for P&R buses and other coaches up the slip road from the A27, with traffic marshals/stewards.
The transport truly is woeful at the Amex, they could do with some joined up thinking on traffic management which is an utter shambles. An improvement here would change the access to the ground not just for car drivers but also for the many coaches travelling in from all over the region, as well...