Narrative:

While 'descending via' to 4500 ft on the oakes 2 RNAV arrival; and after passing waypoint toool; we were subsequently cleared to cross ffist at and maintain 8000 ft. We complied with that clearance. About 3 nm past ffist we were cleared to resume descending via the arrival. Because of the delay; we had to expedite our descent to make the mandatory crossing of 4500 ft at parbb. All the while; ATC was engaged in almost non-stop conversation with numerous VFR aircraft; including VFR flight following and vectors to avoid the oak arrival corridor. We were never given traffic information; but it sounded as if at least one of the VFR aircraft were given traffic information about us. 2 nm prior to parbb; while descending at flaps 1 airspeed (197 kts) we received a TA and almost immediately an RA with a command of 'level off; level off'. We complied with the RA and reduced our descent rate from 700 FPM to 0 FPM and leveled off at 4800 ft. We maintained 4800 ft until about 2 nm past parbb when we received 'clear of conflict'. We then continued our descent to 4500 ft. We advised ATC of the RA; and received a reply of 'roger'. We asked for a continued descent and were cleared to 3000 ft and subsequently cleared for the visual approach to runway 30 at oak. The rest of the flight was uneventful.caused by ATC workload caused by numerous VFR aircraft operating in and around the oak arrival corridor. The controller was task saturated. [No suggestions] without further restricting VFR traffic. The RA occurred at the bottom of or slightly below the constraints of the class B airspace around sfo.

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Original NASA ASRS Text

Title: Air carrier flight crew reported responding to a TCAS RA on arrival into OAK airport. Controller workload with VFR aircraft was a contributing factor.

Narrative: While 'Descending Via' to 4500 ft on the OAKES 2 RNAV arrival; and after passing waypoint TOOOL; we were subsequently cleared to cross FFIST at and maintain 8000 ft. We complied with that clearance. About 3 nm past FFIST we were cleared to resume descending via the arrival. Because of the delay; we had to expedite our descent to make the mandatory crossing of 4500 ft at PARBB. All the while; ATC was engaged in almost non-stop conversation with numerous VFR aircraft; including VFR flight following and vectors to avoid the OAK arrival corridor. We were never given traffic information; but it sounded as if at least one of the VFR aircraft were given traffic information about us. 2 nm prior to PARBB; while descending at Flaps 1 airspeed (197 kts) we received a TA and almost immediately an RA with a command of 'LEVEL OFF; LEVEL OFF'. We complied with the RA and reduced our descent rate from 700 FPM to 0 FPM and leveled off at 4800 ft. We maintained 4800 ft until about 2 nm past PARBB when we received 'CLEAR OF CONFLICT'. We then continued our descent to 4500 ft. We advised ATC of the RA; and received a reply of 'Roger'. We asked for a continued descent and were cleared to 3000 ft and subsequently cleared for the visual approach to RWY 30 at OAK. The rest of the flight was uneventful.Caused by ATC workload caused by numerous VFR aircraft operating in and around the OAK arrival corridor. The controller was task saturated. [No suggestions] without further restricting VFR traffic. The RA occurred at the bottom of or slightly below the constraints of the Class B airspace around SFO.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.