Crash Data Record Systems:
What They Can Do For You by R. Scott Wills and Dennis F. O’Brien
R. Scott Wills is an accident reconstruction expert and partner in the firm of Cover & Wills, LLC in Cockeysville, MD. His expertise is in the areas of Highway Accident reconstruction specializing in collision dynamics, vehicle speed calculations, direction of principal force and occupant positioning. From 1979- 1999 he was with the Baltimore City Police Department where he served as Instructor and Lead Accident Reconstructionist. He has been involved in over 1200 collisions as primary reconstructionist and over 3600 cases in a secondary capacity. He is certified and fully accredited as a Traffic Accident Reconstructionist. He is a frequent lecturer and has served as instructor for many seminars for bar associations, insurance compa- nies and law enforcement entities. He has testified in many jurisdictions in the state of Maryland as an expert witness during trials and at depositions.
Dennis F. O’Brien (Foard, Gisriel & O’Brien, Towson) received his J.D. from the University of Baltimore School of Law. He is a member of MTLA’s President’s Club as an Eagle and is the former Editor In-Chief of Trial Reporter. He also serves as a member of the Legislative Committee and is chair of the Public Realtions Committee. Mr. O’Brien is a member of the Baltimore County and Maryland State Bar Associations and ATLA. His practice concentrates in serious personal injury, products liability, medical malpractice and ap- pellate work.
An accident occurs on a Western
Maryland highway. Three young women in a car are involved in a relatively minor collision with another vehicle. The car, driven by a teenage girl, is pushed against the jersey wall and comes to rest disabled. As the driver of the car calls for help on her cell phone she is stuck in the fast lane of I-68, and several vehicles go around her. Unfortunately, a large pickup truck does
not. It strikes the vehicle on the driver’s side door and kills the driver while she is speaking with her mother on the cell phone. The vehicles traveled several hun- dred feet together after impact. Another vehicle strikes the pickup truck in the rear, after the first vehicles had come to rest. The pickup truck driver tells police he was operating below the speed limit and braked for a substantial time prior to im-
R. Scott Wills Dennis F. O’Brien
pact. While much of the evidence at the scene is preserved, the accident, particu- larly the speed at which the pickup truck driver was operating at the moment he could have perceived the danger, will be difficult, if not impossible to determine using conventional methods. Crush analysis, conservation of momentum, and skid mark length are the usual methods used. For the attorney and accident
reconstructionist, the Crash Data Re- corder (CDR) system provides a reliable, and in this case, telltale method for de- termining critical information about the pre-impact speed and braking of the truck. Crash data recorders or retrieval systems, also known as “black boxes,” are part of the air bag sensor systems that determine when an airbag will deploy.
What Are CDRs and What Do They Do. In the event of an accident, the Crash
Data Recorder (CDR) is a component of the system that determines if the vehicle’s airbag will deploy or not. To be of use, the airbag must deploy in time to protect the vehicle’s occupants. A variety of sen- sors collect vehicle data and transmit it to an “Electronic Control Monitor” or ECM (the black box), which evaluates the data and when threshold values are reached, the airbag deployment sequence is initi- ated. Typical vehicle functions/data that are monitored and sent to the ECM in- clude: vehicle speed, engine speed, throttle position, brake status, seat belt status and Delta-V.
History of the System. Automotive airbags were first intro- duced commercially in the early 1970’s
18 Trial Reporter Fall 2003
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