In this, the fourth of a series, Popular Science profiles one of the favored teams competing to win the Darpa Grand Challenge autonomous-vehicle race, which will take place on Saturday, October 8, near Primm, Nevada. Today we look at the Virginia Tech team's two entries, each of which takes a different approach to the problem. Stay tuned to popsci.com for more previews throughout the week and for minute-by-minute videos and updates on race day.

Virginia Tech Team
Blacksburg, Virginia