Imagine that after you parked your car under a tree, for some odd reason a tremendous amount of tree sap spilled all over your windshield. We're talking gallons and gallons of tree sap, and the sticky substance ocvers your window, hardens, and makes it nigh-impossible to see out of your car. If this bizarre scenario were to afflict you and your car, you would clean off the entire windshield. You would not clear out a small foot-by-foot chunk of the winshield so that you could see out of it, and then hope the rest of the sap fell off because of natural processes, right?
Now, apply this same thought process to the winter. Illinois residents know it all too well: the snow falls, it freezes to your windshield, and you have to dig out the ice scraper from the back of your car to clear off your windshield.
However, in a fit of laziness, you decide to cut out a small portion of the ice and just drive. You've basically given yourself tunnel vision, except you're driving a powerful motor vehicle. Perfect.
This behavior is now being called "peephole driving," where an iced over windshield has a tiny clearance cut out for the driver to see -- and it's very dangerous. Peephole drivers cut off their own peripheral vision, let alone reduce the amount of the road they can actually see. Going out on the road with an uncleared windshield is irresponsible and reckless, and it could make such a driver liable in civil court if he or she causes an accident.
Source: Star Tribune, "'Peephole Drivers' Ignore Safety and Law When They Don't Scrape Cars," Kim Ode, Jan. 5, 2014