If any cab driver is taking you into Manhattan from JFK via the Tappan Zee then you are certainly going hours out of your way (The Tappan Zee is way north of the George Washington bridge on teh west side). If you mean via the Tri Borough, then they are probably taking the route of least resistance, it's allmost always the better choice then the tunnels are.

How do they know? There are traffic reports every three minutes on the radio in New York, so they grab one of them every hour or so, and it will say how far the backups are in the tunnels and bridges. If they say the midtown has a 45 minute backup, then you know it will be at least an hour before you consider it again (stations - 1010 on the 1's, 880 on the 8's, and 1350 on the 5's)

(edited to correct times of traffic reports)

[This message has been edited by cordelli (edited 12-22-2000).]