I have an idea that would improve the flow of traffic, make travel safer, and improve driving overall for everyone, and I wonder why no one has come up with this idea before. Automakers are trying to make cars autonomous, each car controlling their own destinies and individual safety. Why don't they make it so cars communicate with each other, creating a grid that each car knows their position and speed and tells all the other vehicles around them that information. That way, all cars automatically make adjustments to changing road conditions.
Rather than an autonomous vehicle only relying on itself to keep its lane position and speed by relying on its own observations and calculations from laser, GPS, radar, and cameras, all cars would tell each other "I'm here, this is my speed, this is where I'm going, and this is the condition of the road around me." When the car ahead of you needs to slow or or maneuver in any way, it would tell your car what it is doing, and your car will automatically react and respond as appropriate. It wouldn't have to interpret and react to external stimuli because it would know what is going to happen as it's happening instead of reacting to the consequences of the observed situation.
Instead of a car reacting to a situation individually, then each car behind that one reacting to its actions, the first car would notice and react to a given situation, and immediately tell all cars around it "There's a dog in the road. I will be stopping and taking these evasive maneuvers." Thus, all the other vehicles know what is happening and will react accordingly without the delay caused by ones' recognition of a situation, processing it through your brain or autonomous computer and instruments, then reacting appropriately or inappropriately. All surrounding cars would know what is happening before you do and react accordingly, thus avoiding collisions caused by delays in action on the individual's part.
This would not need major infrastructure changes. Each individual vehicle would be part of the system. The only elements outside of the automotive grid would be traffic signals telling cars "I'm turning red or green", and approaching vehicles would react as appropriate.
This could eliminate collisions, especially those due to distracted or drunk drivers. No more high speed chases by police. And the grid would detect and report situations to appropriate authorities immediately, without individuals having to call 911.
Say a pothole suddenly develops on 101. Car #1 hits it. Car #1 tells the grid "There's a pothole at this position!" The car behind him reacts to the pothole before its' driver observers car #1 blowing out a tire and swerving. The grid would immediately report the pothole to CalTrans and CHP.
Just think how much time, money, aggravation, and lives a system like this would save. It would, however, take away a lot of our individuality and independence away from us, so it will probably never happen.