I think human factors such as drunk driving, phone usage, speeding and skill level are still the main contributors. I couldn't find a good source about global figures, but there is this research about Saudi Arabia specifically: http://www.sciencedirect.com/science/article/pii/S0033350600003061, which states that "Over 65% of accidents occur because of vehicles travelling at excess speed and/or drivers disobeying traffic signals". These human causes can possibly be solved by technological advancements such as automatic pilot technology, a definitive solution to that could be an integrated network of all vehicles, which needs to be somehow protected from hackers..