Fuel cell to cease dependance with oil suppliers and greatly reduce smog in cities.
Adaptable shell to carry more people or take less space if driving alone.
Adaptable contour seats with accupressure for greater comfort and safety (keep driver alert and relaxed)
Computer that evaluate the driving risks based on weather, mechanical status, road conditions (pavement quality, construction, etc) and make suggestions based on driving experience, mental state, fatigue, car noise level (kids), etc
Computer would compensate for driver physical state by altering cabin oxygen level, music level, etc
Active windshield would have information overlay and would enhance edges and display tags on objects to enhance visibility
Glider. A glider is not affected as much by pavement conditions, use and friction. Can also go over snow, sand and offroad without getting stuck.