Owners of the 2012 GMC Acadia midsize crossover can safely merge onto the highway using technology similar to what fighter pilots use to guide precise movements at supersonic speeds. The vehicle’s optional heads-up display, or HUD, was born out of aerospace research. Acadia’s HUD works by projecting information from within the dashboard, using two mirrors to reflect a crisp digital image off the windshield so that it appears to the driver to be floating in front of the vehicle’s bumper. Drivers can adjust the brightness of the image, its location on the windshield or even turn the image off altogether. Viewable information includes speed and tachometer readings, vehicle warnings, turn signal activation, outside temperature and other vehicle and radio information.