There's a glass roof — but no rear-view window. Instead the Polestar 4 replaces the rear-view mirror with a live feed from a wide-angle camera . Its high-resolution display (1480 x 320 pixels) promises "a panoramic view of the outside," according to Polestar's web site, showing more of what's behind you. "Visibility in the dark and in rainy conditions is also vastly improved." Besides the camera feed (and side mirrors), the Polestar 4 offers four short-range cameras (for 360-degree views), and even short-range ultrasonics, the Wall Street Journal points out . (Car rear-view windows are usually five feet off the ground, "making a typical traffic cone invisible from closer than about 35 feet." ) And this new design also improves "aero efficiency," reducing drag and shearing turbulence, "critical, since the Polestar 4 is all-electric, and aero drag is the mortal enemy of range." [A]s a practical matter, the Polestar 4's innovation only acknowledges what drivers already know.…