Image by ER24 EMS (Pty) Ltd. via Flickr - Joe Fried and his firm are to me the consummate trucking lawyers. He's accomplished and to be blunt, knows his stuff. Here's a guest post from Joe:
I recently was asked to do a presentation to a bunch of lawyers and police officers on the current state of technology with tractor trailer black boxes. So, I had to brush up to make sure my information was current. I thought this may be useful to some of you who handle tractor trailer cases.
Most large truck engines have an engine control module (ECM), sometimes called a black box or an Electronic Data Recorder (EDR), that is responsible for monitoring and controlling important engine and vehicle parameters, such as speed, throttle, and braking. You can download this information from the truck engine, but what exactly you should expect to get depends very much on the manufacture of the engine and the date of manufacture.
In this post, I present you with what you can expect from a Caterpillar engine. If you would like to know what to expect from other manufacturers (Detroit Diesel, Mack, Cummins, International), shoot me an e-mail at joe@thetruckingattorneys.com (Put “ECM paper” in the subject box) and I will get you a copy of the entire paper. The powerpoint slides I used in my presentation is available at Slideshare.com.
Here is the skinny on the Caterpillar black box ECM:
Used in many Peterbilt, Kenworth and International tractors.
Caterpillar engine ECMs have been able to record sudden decelerations (“quick stops”) since 1995, but the factory default was set to not record any such data. Some customers change this threshold but not many. For these engines, there is no way to determine with the data will be recorded without downloading the box.
Starting in 2007 the engines started being shipped with “quick stop” function set to “on.” This was the result of new environmental standards. The quick stop record contains 45 seconds of data before the threshold is met and 15 seconds of data after the threshold is reached.
The Quick Stop Record contains:
· Wheel speed (mph)
· Engine load (percent)
· Service brake status (on/off)
· Clutch status (on/off)
· Cruise control status (on/off)
· Other parameters defined by end-user
Caterpillar engine ECMs will also record a report called a “snap shot” if the engine senses a critical fault in the engine such as dangerously low oil pressure. When triggered the ECM will capture about 9 seconds leading up to the fault and 3 seconds after the fault is triggered. This can be useful in timing a collision, but it is not nearly as helpful as a DDEC.
