We were on vacation last week in Breckenridge, CO. I enjoyed it, although it did take me a few days to acclimate to the 9600 feet altitude. Returning on I-70 East, we saw some great road signs:
Truckers don't be fooled – 4 miles steep grade
Truckers you are not done yet – 1. 5 miles to go
These road signs are different enough from other signs that drivers and passengers pay (even more) attention to them. The message that even though the road looks like it's flattening out a bit, it's not — that the drive is still risky.
Project managers choose a different action when they know it's close to the end of the project. Instead of slowing down as truckers (and the rest of the drivers) should, PMs know it's time to maintain the pace of the project. If you let people off the project before the project is complete, it will take longer and cost more to complete the project.
I was a program manager for a 100+person project a number of years ago. Four weeks before the end of the project, the company laid off one-third of the project staff. It took the project another nine months to complete. Now, it's possible we wouldn't have made the original date, but as far as I could tell at the time, we were on target, possibly as much as a week early.
Project managers, focus your project team on the ultimate date, not a penultimate date. Maintain a reasonable project momentum, you don't risk crossing the desert watching your success being snatched away.