Reviewing the Traffic Study prepared for the Concourse Garage EIR:

Traffic flow is measured by 'intersection courts.' Below are the projected counts for the intersection of 10th Ave and Fulton, First Baseline with both institutions open, but no garage, and them the same about of traffic, but with the Garage entrance at 10th.

Doing the numbers we find that;

BUT what if there is only one garage entrance (on the north)

For those that likes charts this means:

Only
on Sunday would there be an increase in taffic on 10th between Fulton and Cabrillo.
(Recall that currently 10th Ave is closed into the Park on Sundays!)
But what of the impacts to Fulton's traffic:

CONCLUSION: Generally, traffic on 10th Ave. north of the Park will be reduced with the Garage WHATEVER happens, and the impacts to Fulton are minimal. Remember this does not consider closure of the Concourse to throu-traffic which is found to reduce Traffic entering the east end of the Park by another 30%.