Fonts

An interesting study:

Results showed male subjects had an easier time recognizing Frutiger and thus spent less time glancing at the display and more time focused on the road ahead. Average glance time with Frutiger was 10.6 percent lower for men, and while that may sound insignificant, researchers say it works out to about 50 feet when traveling at typical highway speeds.

And people pretend that fonts don't matter.