I got into an accident in March and I was wondering if there is a way of checking how fast the car was going on impact. I know that the police will also use skid marks and such to figure that out but is there a way of getting the speed directly from the car? Like from the ECU or something? Do the airbags record the speed of the car when they were deployed? btw, I had a '99 ES.

Nathan

 

No, the ECU or Airbag system doesnt record your speed of the car...the only way you can know now, is by tryin to remember...

 

Is this a fact? I'm just checking because the police said I was going a certain speed which I disagree with so I'm just wondering hwo they figured that out. It was raining when the accident happened so they didn't have many road marks to do much with.

So the only way they could tell how fast I was going is the actual damage of the 2 cars and the tire marks on the road?

 

Accident reconstruction specialists are VERY good at what they do. Skid marks, damage incurred, angle of impact, etc. There are literally thousands of things they take into account to judge approach speeds.

BTW, some cars have VERY sophisticated ECUs. My Volvo for example, will store speed readings for certain things such as airbag deployment, when faults (check engine codes) occur, as well as some other things. One person that brought their Volvo in for a check engine light that came on while he was doing a high speed run, became famous. When they hooked the car up to the OBD-II and Vadis system, they found that the ECU recorded the fault at a speed of 235km/h.

I have noticed that the Maxima diagnostic system is not nearly as sophisticated as my Volvo's so I can't say the same for the Maxima. But I'm just saying, many cars do.

 

New Corvetts have a "Black Box" in them that records various driver activities such as speed, brake force, and accelleration. When Corvette owners discovered that they were being monitored, it caused a bit of an upset. The reason for the black box was to freeze exactly what the car was doing in the case of an impact. They were using the information for safty reasons. Some Corvette owners demamded GM disconnect this system. I don't recall if GM still puts that Black Box in their cars. This all came about around 3 or 4 years ago. Car and Driver had a full report on it.

I think Caddys were also equipped with this device and still might be.

 

I think that's cool, it would be nice to bring that into court to fight a ticket.

 

Measuring skid marks is one way of determining speed, but there are many other ways. What if there's an accident involving a car with ABS brakes? You won't have skid marks from the wheels locking up. Or what if the driver just doesn't break?( fell asleep at the wheel). Accident reconstructionist have many different formulas and tools to determine speed.

The lastest tool being an instrument called " the Total Work Station" It's an instrument that looks like a surveyor tripod setup. With this tool, police can record measurements, slopes and elevation. From this they can make an accurate scaled down drawing or model of an accident scene.

 

Does anyone know how fast you have to be going for the airbags to deploy?

 

When I had the accident it was raining outside so I doubt there was a lot of skid marks on the road. If there weren't many skid marks for the police to work with what else can they do to determine the cars speed at impact? Do they seriouly take into account witnesses stories?

Nathan