In reply to:

My contact at NavTech tells me that the TIGER data is notoriously inaccurate.


It's quite obvious if you spend any time at all browsing the Census Tiger mapping site for any area you might be familiar with. And ignoring the question of the data being out of date, some USGS maps weren't accurate when they were current, either. A highway ramp near me is missing, probably photorevised away by the looks of it, despite having existed continuously since about 1952.

NavTech isn't perfect, either, but they certainly are (demonstrably) better than raw Tiger.