Is There A Crash Scene In Right On Track

What is the worst car crash you've ever seen or experienced?

20 years ago - 1996 I think it was - I was driving back home with my then gf from Auckland (I lived 160km away). It was raining and I was speeding because I wanted to get home in time to watch the X-Files. I was an idiot.I came zooming round a corner at 120kmh and found a bus stopped in the middle of the road. I found it very interesting just how time really does slow down in these high-adrenaline situations. In the second or so before I hit the bus, I saw a car coming the other way on the other side of the road and immediately weighed up that overtaking the bus was a bad idea as that would mean a head-on with the oncoming car, which means greater combined force. On the side of the road was a deep ditch and again I realised going that way would be certain death. My only option for survival was hitting the bus. As I made my decision, I turned to my gf and said, “I'm really very sorry about this.”All this in about a second!We hit the bus but unfortunately the bus was high up and instead of smacking into the back of the bus, we went under it!The force of the collision tore the side struts off the car windscreen and crumpled the roof. By sheer dumb luck my car hit the bus's back tires, and this stopped our progress. The back of the bus ended less than an inch from my face. Another foot or so…I ended up with a tiny scratch on my thumb. My gf was less lucky being seated further forward. The top edge around the windscreen hit her head so she was bleeding rather profusely but fortunately not seriously (headwounds are messy). Later when she was taken to hospital we found she also had whiplash.The fire dept were already there due to road flooding (which was why the bus was stopped). One of the firemen cheerfully offered me my car's radiator cap - he found it 2 cars in front of the bus. This should give you some idea of the force of the collision.Had I driven for the road conditions - say at 90kmh - we would have missed the first 5 or 10 minutes of that evenings X-Files episode. As a result of rushing we missed the entire episode, destroyed the car and ended up spending half the night at the hospital. Oh, and I got a traffic infringement ticket.There's probably a moral in there somewhere…

Formula one - Why did Ayrton Senna's head move after his crash? How did his injuries kill him and how quick was his death?

The telemetry shows that Senna's car left the road at the Tamburello corner at 310km/h, before hitting the outside wall at 218km/h.The angle with which he hit the wall caused the right-front wheel to tear off upon impact, entering the cockpit and hitting Senna on the front part of his helmet. The violence of this impact caused his head to push back against the headrest, causing massive skull fractures.In addition, a piece of suspension had partially penetrated his head, and another piece just above his right eye.An emergency trachetomy was performed at the time, and Senna's breathing was artificially maintained. He was placed on life support after being flown to the nearest hospital. After having his heart restarted once, it once again stopped beating at 6.37pm, and at 6.40pm he was officially declared dead, some five hours after the accident.Given the severity and nature of his injuries, it is likely that Senna was, for all intents and purposes, dead upon impact. The moving of the head was an involuntary spasm consistent with a massive head injury. Persisitance accomodative spasms and spasticity is common with patients who have experienced brain trauma. More information can be found here Page on nih.gov. It may be a combination of brain trauma and loss of blood that killed Senna.

After a car crash, how would police investigators tell the speed of the cars prior to the crash?

How they would tell the speed of the vehicles very much depends on the level of investigation they are doing.  For standard investigations, your simple motor vehicle crash report, the officers will interview the involved parties and any witnesses that may be available.  In their interviews the police will ask about the speeds of each vehicle, weigh the credibility of the parties giving evidence, observe the vehicle damage and any other physical evidence (skid marks, areas of property damage, etc.) and give their opinion as to the probable speeds of the vehicles.  Of course, sometimes it's super easy as speedometers often will get stuck at the speed they were recording after a collision.  For simple collisions this is good enough as it is not really necessary to know the exact speed of the vehicles involved.Sometimes, for serious collisions, the police will do a technical reconstruction.  A technical reconstruction is done either by specially trained officers or by engineers (most police forces use officers trained for this purpose because the cost of employing engineers is high, insurance companies will retain engineers for this same purpose).  The reconstructionist will study the physical evidence and the witness testimony.  They will take measurements of the road, the vehicles, any marks on the road, any damage present, etc.  From this they can often calculate the velocity that a vehicle was going.  They will also measure the amount of crush damage to each vehicle and contrast that with control data on similar vehicles in order to determine what the change in acceleration (delta v) between the vehicles was, which tells them the speed of one vehicle relative to the other... so if you can figure out the speed of one you can then get the speed of the other.  Often, they will also download the event data recorders from the vehicles (air bag modules, power-train modules, VORAD systems, etc.) which often record the exact speed of the vehicle, throttle input, steering input, and breaking input, amongst other things depending on the systems accessed (VORAD systems can actually give an exact location of other vehicles and objects relative to the radar for several seconds to a minute prior to the collision) and the manufacturer.  From this data they can calculate the actual speed and actions of the vehicles involved with incredible precision.