How about having vehicles fitted with accident free sensing device which could be turned on while driving on high ways. The device will sense the closeness of two vehicles and based on other factors like speed, distance, friction, wind factor, traffic load will calculate the chance of accident. Accordingly the vehicle should take alternative response methods either through self resolution by slowing or sound alarm to the driver. There could be n factors which needs to be calculated at spur of time.
I don't have any basis or indepth though process on this idea, but this have been poping in my mind for quite some time and today i stumbled on this website and thought of putting it forward to wider audience.