Chapter 82: What The Box Writes Down
I need to explain the technology, because everything after this depends on it.
It is not magical. It is a switch, a clock, and a table.
The part is called the airbag control module. Some manuals call it the restraints control module.
Technicians call it the black box, which is wrong and makes people expect a cockpit recording.
There is no sound. There are no words. There is no camera.
What there is, is a table of numbers with column headings.
The module's real job is to decide, in about fifteen milliseconds, whether to fire the airbags and how hard.
To do that it has to know things.
How fast the car is decelerating. Whether the belts are buckled. Whether anybody is sitting in the passenger seat. How far forward the driver's seat is on its rail.
It asks all of those questions many times a second, all day, forever, and throws the answers away.
Then something hits the car hard enough, and it stops throwing them away.
It writes down the last five seconds and locks them.
That is the whole invention.
A machine that is always forgetting, and forgets in a specific way, and once in its life does not forget.
I read about this for eleven days in a public library, on a computer with a forty-minute session limit.
Which meant I read about it in seventeen sessions.
I took notes on the back of scrap paper from Marisol's recycling. Fifty-two sheets.
Here is what the module on a Ford of that model year stores when the airbags deploy.
Vehicle speed, once per half second, for the five seconds before impact.
Engine throttle position, same interval, as a percentage.
Service brake, on or off, same interval.
Driver's belt switch: buckled or unbuckled.
Front passenger's belt switch: buckled or unbuckled.
Passenger occupant classification: whether the seat sensed weight, and roughly how much.
Time from the start of the crash to airbag deployment, in milliseconds.
Time to the belt pretensioner firing, in milliseconds.
And one more line, which is why I stopped being able to sleep properly in April.
Driver seat track position switch: FORWARD or NOT FORWARD.
That switch is a small plastic sensor mounted on the driver's seat rail. It has one job. It tells the module whether the driver is sitting inside a certain distance of the airbag.
The distance is not a guess. The manufacturer sets it.
On that platform it is set at the forward-most portion of the track travel, and the reason it exists is that if you are short enough to sit that close, a full-power airbag can break your neck.
So the module reads the switch, and if the driver is sitting that far forward, it deploys at reduced force.
It is a safety feature for small people.
I wrote that sentence down on scrap paper on the twenty-second of April and underlined nothing, because at that point it was just a column heading.
The tool that reads the module is called a Crash Data Retrieval system. It is made by one company.
It costs about eight thousand dollars for the interface and the annual licence. The licence is what matters, because the software is what knows how to translate the numbers for each model.
You cannot buy the data. You buy a translation.
There are maybe eleven people in this state licensed and insured to do it for court work.
I found six of them on a certification directory. I wrote to all six.
Four never answered.
One answered with a form email saying his practice was retained exclusively by defense counsel and insurers.
The sixth was a woman named Anneke Sirko, who wrote back in two lines.
“$475 flat, includes report. I need written consent from the vehicle's owner and I don't work on cars I can't reach with a van.”
I read those two lines nine times.
Not because of the money, although I had $61 and rent on the fourteenth.
Because of the six words at the end of the first sentence.
Written consent from the vehicle's owner.
In this state, and in most, the data in that module belongs to the person who owns the car.
Not to me. Not to the police, without a warrant. Not to the son of the woman who died.
To whoever currently owns the metal.
The current owner of the metal was a man in Wheeler's Gap named B. Kessel, who had bought a shell for six hundred dollars, never registered it, never titled it, and let a tree grow through it.
He had no title. He had a bill of sale from a salvage yard and a field.
And in order to prove I did not kill Nadine Okoro, I now needed that man to sign a piece of paper.
I want to say plainly what I thought when I understood that.
I thought: of course.
Of course the last door is a signature.