Nick I'd say that as long as they're are vehicles of significately different sizes/weights running together on the highways, and the fact that cars are built to a cost, means there will always be fatalities in the lighter one. I think the big question is, how much of them could be avoided if there was strict training for drivers and strict enforcement of standards, for them and for road design. How many times have any of us seen someone cut off a truck, suddenly turn, and otherwise not seem to understand the potential ramifications of their actions. I used to do about 20 miles each way to work on I71 here in southern Ohio and the number of people I saw who seemed unaware of how close they came to greeting God was troubling. If we want to decrease injury and death that in my opinion is the one thing that would make a real difference.
We regard driving as a right, while in other countries it is a privilege. I'm not saying either is the only way, just different. I was in Germany long enough to have to take my driver's test, and you are not even allowed to book it until you have completed a state-run course and passed the written test (rather like private pilot). The failure rate was around 45% on either the written or road test. And you can be pulled over and fined for doing any of the things many Americans consider Ok, like using a cell phone, drinking coffee, eating a sandwich etc.
It's very similar in France, which has road-side "courts." The tests in all European countries that I have been in involve both city and highway driving, and you can be failed for going too cautiously. In Germany I was warned of this, and told to drive at the speed the posted limits and road/traffic conditions allowed. Europeans taking the typical US test, with its slow-speed crawl round a marked course behind a police barracks, plus the dreaded parallel parking, are amused and horrified.
When I took my British test in the 1950s, auto transmission was a virtually unknown luxury. Part of the test was to park on a steep hill, whereupon the examiner would get out and place a wooden match box (empty) behind a rear wheel. You had to start off from rest, using handbrake, clutch and throttle judiciously, together, to get moving without crushing the box (or, "sorry, see you in six weeks.") If you took the test in an auto trans, you license was endorsed and you were not permitted to drive a stick shift unless you passed the test in that.
However, all that and above; yesterday the US Dept. of Trans. reported the lowest traffic fatalities in the US since 1954 - almost
10,000 less than ten years ago. Seems more use of seatbelts and an increasing crackdown on DUI are responsible.
Bill: You can actually ram the transmission into PARK while on the move. The parking pawl is designed to skip over the teeth of the cogwheel at anything over 5 mph or so, to prevent locking the wheels.
Stop Press: Seems the Prius guy may have been trying to get some dough out of Toyota by faking the problem. Seems he went bankrupt some time ago, owes $700,000, and is even behind in his Prius payments. So maybe he is a liar after all.