The Lake O'Hara region is VERY fragile & would be literally loved to death if Parks Canada did not control access. There are no quotas for those who choose to hike the 11 km uphill grunt from the parking lot to Lake O'Hara. Alternatively, a scheduled bus makes several runs daily from mid-June through late September. Bus reservations are required -- there is a quota system, and the busses fill EARLY.
Thanks. Cheers William