Name the driver for race time being 2:34:21
CREATE TABLE "table1_16493961_1" (
  "year" real,
  "date" text,
  "driver" text,
  "team" text,
  "manufacturer" text,
  "laps" text,
  "miles_km" text,
  "race_time" text,
  "average_speed_mph" text,
  "report" text
);
SELECT "driver" FROM "table1_16493961_1" WHERE "race_time"='2:34:21';