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This topic comprises 4 pages: 1 2 3 4
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Topic: Turning Off Headlights in Drive-In
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Randy Stankey
Film God
Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99
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posted 06-21-2005 09:55 AM
I've heard about that story.
The "black box" is the PCM (Powertrain Control Module AKA: "Engine Computer") itself and not some extra box secretly installed somewhere. It's part of the OBD II (On-Board Diagnostic) spec. that's part of most/all cars built today.
The PCM records all the data from the last 20 starts, I believe. It is supposed to use that data to keep the engine running most efficiently and to help a mechanic/technician figure out what's wrong in the event repairs are needed.
It does record data that would tell you how the car has been accellerated via a Throttle Position Sensor but I don't know if they have a brake position sensor. I imagine that information could be deduced from the other data, though.
You WANT the PCM to record this data for you.
If you are driving in heavy traffic with lots of stops and starts the computer can adjust the fuel mixture to make the engine run more efficiently. If the car has stalled recently the computer knows that there is likely to be unburned fuel in the cylinders and could momemtarily "lean" the mixture to compensate. If part of the engine/emission system is out of whack, the engine could run ineffiently or not at all. The engine computer can tell you that.
I had a car where the EGR valve stop working. (The EGR - Exhaust Gas Recirculation - recirculates some of the hot exhaust gas back to the intake manifold to improve starting in cold weather and to increase fuel burning efficiency and to reduce pollution.) The valve is supposed to remain open until the engine reaches a certain temperature. Then it momemtarily opens and closes depending on what condidions the PCM senses.
The car would run great in warm weather but it would run terribly in cold weather until the engine warmed up. I took it in to the mechanic. He hooked up the readout device and said, "Let's go for a drive." We had driven less than a mile when he said, "Looks like your EGR valve isn't working." He replaced the EGR valve actuator and the vacuum hoses that operate it and the car ran perfectly. It only took a few hours to fix. If it wasn't for that OBD system it might have taken days or weeks to figure out!
I have heard where people have been involved in accidents/traffic violations and the PCM in their cars was read out to see their driving habits but I believe none of those cases have survived because of the Fourth Amandment. (Search and Seizure.)
The theory is thus: You own the car and everything in it, incuding the PCM and all the data therein. You have a right to expect privacy inside your own car ALMOST as much as you would inside your own house. (Insofar as you drive your car in public.) Therefore, if somebody went into your car and took the data out of that computer without your permission it would be the same thing as somebody searching your house.
If somebody wanted to look at that data without your permission they would need a warrant.
Furthermore, if they were looking at the data for one reason and found OTHER information they could not use that against you unless they had a warrant beforehand.
Let's say they suspected you of kidnapping. They know you had the victim in your car and wanted to know where you had taken him. They could get a warrant to poll the engine computer to find out how far you had driven and thereby deducing likely locations where you have hidden the victim. However, if they also found out the computer says you were speeding they could not use that data to give you a speeding ticket unless that was asked for in the original warrant.
Now, the final question is: How likely are the police to go through all the time, trouble and expense to get a warrant to search your PCM, then to pay a technician to read out and interpret all that data simply to give you a speeding ticket?
Not very!
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Randy Stankey
Film God
Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99
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posted 06-21-2005 01:46 PM
From what I know, there is no real-time clock inside the unit. If there was, how could it stay syncronized? You can't guarantee that the PCM will be able to get a lock on the atomic time signal from WWV, et. al., whenever it's needed. Therefore, any real-time clock could never be guaranteed accurate.
I don't recollect there being a memory inside the unit that lasts for more than the last 20 (or whatever number) starts. Newer units may have more functions than I was made aware of when I was working on the problem with my old car.
In a 1995 Dodge Neon, if you wanted to erase the PCM's memory all you had to do was disconnect the battery and leave the unit without power for 15 minutes or more. When I first had my engine trouble that was my first step... reset the PCM... so that we could prove wheter it was a problem in the engine itself or inside the PCM. (That vintage of Neon had a history of PCMs freaking out. If that happened, resetting it solved the problem temporarily.)
Sure, resetting the PCM will probably erase any data that could tell somebody whether you were speeding but you will likely have to put up with a rough-running engine until the PCM rebuilt its "database".
Even IF it was possible to easily get a read-out on whether the PCM detected that the car was speeding there would be almost no way to prove that a given driver was driving the car in an unsafe manner. They would literally have to pull the driver out from behind the steering wheel, tow the car to an auto mechanic's garage, impound the car and extract the data BEFORE the car was started up again. They would have had to get a search warrant BEFORE the fact.
By the time they went through all the time and trouble to "prove" that you were speeding it would have been much simpler to put a cop by the side of the road with a radar gun! (Or whatever speed detection device is appropriate.)
All of that assumes that the owner of the car hasn't tampered with or reset the PCM before the cops or insurance company have tried to read it out.
PS: Isn't it standard procedure for the fire department to disconnect/cut the battery cables when they respond to an auto accident? If so, then PCM data is likely to be erased before the vehicle is even towed from the scene. No?
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Adam Fraser
Master Film Handler
Posts: 499
From: Houghton Lake, MI, USA
Registered: Dec 2001
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posted 06-22-2005 12:43 AM
The black box thing happened in Traverse City, MI and the guy was doing 71 in a 55 or 45 mph zone and a teen pulled out in front of him and was hit and killed. They pulled the box and convicted him of driving too fast, but I believe a lesser charge.
Here is a link from google
LINK
"Grand Traverse County Prosecutor Dennis LaBelle on Tuesday authorized negligent homicide charges against Kalkaska's Timothy Schubert, 37, for allegedly causing the South Airport Road accident that killed Adrian Morris and Christan DeWitt, students at Traverse City West Senior High. An investigation by the Grand Traverse County Sheriff's office pointed the blame at Schubert by using witness testimony and a "black-box" computer chip taken from the man's GMC Envoy.
Using information gleaned from the chip, sheriff's officials said it appears Schubert traveled between 68 and 74 mph just seconds before the accident occurred, well over the 45-mph speed limit. According to the Secretary of State, Schubert's driving record includes several past license revocations and three speeding tickets since May of 2003."
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Tim Reed
Better Projection Pays
Posts: 5246
From: Northampton, PA
Registered: Sep 1999
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posted 06-23-2005 04:30 PM
quote:
In Europe, truck drivers... have to put a round paper card into the speedometer.
That's a tachograph. Trucks in the US used to have those years ago. They were primarily for hours of service compliance, but some drivers used to get paid by them.
Now we only have to keep written log books, which are easily "cooked" if you know how to do it (heh-heh-heh ![[evil]](graemlins/evil.gif) ). Athough, a DOT (Dept. of Transportation) officer can give you a speeding ticket if your logbook shows you went, say, 120 miles in an hour and a half.
There is pending legislation which will require so-called "black boxes" be installed in every commercial vehicle, to keep track of driving time and force sleeper berth breaks. This isn't as good as it sounds, however, because it doesn't take into consideration things like being stuck in traffic, or shutting someone down 10 miles from home.
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