Going from 8 minutes down to 15 seconds. Not bad. What's the secret?

Synchronizing the traffic lights. 

I'm talking about my evening commute home. There are a set of 4 traffic lights I hit to get out of my Microsoft building and onto the closest highway (520 westbound).  They used to be out of sync such that you'd get green lights when the traffic in front of you was already backed up; and red lights when it was wide open.  (I think in those cases, the lights were optimized expecting a different  traffic pattern then what actually happens)

Generally, if you have a bunch of traffic lights in a short section of road, you want them all green at the same time so that traffic can flow through all of them without getting stuck in between lights and causing backups.

Before they were out of sync, and I'd be sitting at the same light through multiple red / green cycles. Now they're "fixed", and I can literally get through all 4 of them in one clean motion.

 

Applications to software:
- contention can kill performance.
- optimizing for the wrong scenario (in this case, wrong traffic pattern) can kill performance.