Starcraft 2: Roaches do not stop Bunker Rushes

I was trying this new(er) Zerg build order:

• 15 pool
• 14 gas
• 16 hatch
• 18 Roach Warren
• 18 Overlord
• 18 Overlord
• 8-10 Roaches
• Queen

... but it's still weak to a bunker rush IF YOU LET THE BUNKER FINISH.  The Roaches do NOT counter a completed bunker (unless you can hit it from the high ground, maybe), and DEFINITELY does not counter the ramp double-block.  I suggest going Banelings if you get contained, and break out ASAP and counterattack - you'll be too far behind otherwise, especially if your expansion hatchery is destroyed.