Modern cars practically drive themselves and need far less maintenance than those of just a decade ago. There is room for improvement, however, and I’ve got some suggestions. 
  I’d put a bright red brake light in the center of the dashboard. It would light up only when the brake pedal was lightly depressed, when it was in that range between brake-lights-on and brakes-applied. It would come on only if the pedal stayed in that range for more than a second. 
  That would take care of the driver who cruises with left foot resting on the brake pedal, never considering that the brake lights are on. 
  Such a light would reduce accidents. People who brake with their left feet are the ones who stomp both pedals to the floor in emergencies. The engine usually wins. If the driver survives, he then sues the car’s manufacturer and swears that the car accelerated all by itself and caused the crash.    
  I’d also modify turn signals. If a turn signal is on for more than ten seconds with the car in motion, the clicking sound will get progressively louder until even the most unobservant driver would realize the signal was on. Eventually, for those oblivious to anything short of a train wreck, the car’s computer would offer a gentle reminder such as, “If you don’t turn off your turn signal, I’m going to seize your crankshaft.” 
  No more driving down the highway for miles wondering if the guy in front of you is really going to turn or change lanes, or if he’s merely unconscious. 
  I might even add another turn signal feature for cars sold in Clallam County. Local drivers tend to use the turn signal to indicate what they just did with the steering wheel. I’d have the computer say, “Remember, please, and this isn’t difficult. It’s signal first, then turn the wheel.” 
  Now we come to parking lights, those little red and amber lights that don’t help you see where you’re going and are nearly invisible in a stream of headlights on a highway. What they’re for is to help other drivers see you when you’re parked beside the road. That’s why they’re called parking lights. 
  I don’t know why some people refuse to turn on headlights until they can’t see without them. 
  There’s a reason why the times near sunrise and sunset are the most dangerous for driving. It’s because those with the sun behind them can see clearly and don’t have lights on. Those coming toward them can’t see a damn thing except vague shadows against the sun, shadows and headlights, if any. 
  I’d put a transmission and parking brake interlock on the light switch. If a car is not in park with the brake set, the parking and dashboard lights would not come on. Once on, the transmission and brake would be locked until parking lights were turned off or headlights on. 
  This feature wouldn’t be necessary if all cars and trucks had daytime driving lights, but they don’t. 
  Comfort can be improved simply by going back to the way things used to be. 
  About 40 years ago, the sides of cars changed from straight-up-and-down to curved. The ads touted the increase in shoulder room, but they lied. All they did was reduce headroom. 
  You could leave windows down a couple of inches for ventilation in an older car without rain soaking the seats as it sat in the parking lot. 
  One of my earliest encounters with the “improved” design almost tore an ear off. 
  It wasn’t my car, and I wasn’t familiar with the new, two-door hardtop. There was just enough room in the crowded parking lot to open the door and slip inside. As I dropped into the seat, the curved window caught me under the ear. I won’t repeat my assessment of the designer’s ancestry. 
  There are many ways to improve car design. You probably have a couple of ideas, too. All the manufacturers have to do is ask us.