Passenger Vehicle Event Data Recorders: What are they and how are they useful?

Event Data Recorders, or EDRs, can store data such as vehicle speed, driver steering, and brake application for up to several seconds before a collision, as well as data like collision severity during a collision. EDRs are present in most passenger vehicles on the road in the United States, and nearly all new vehicles have one, even though it is not a requirement.

Understanding EDRs

EDRs can provide useful information about an event, which can be used in conjunction with physical evidence, to conduct an accident reconstruction. EDRs are also referred to as “black boxes,” analogous to the term commonly used for flight data recorders. Aircraft “black boxes,” which are actually bright orange, often consist of two components: 1) a flight data recorder, which can record information like speed, fuel status, and temperature, and 2) a cockpit voice recorder, which can record conversations on-board and with air traffic control and have up to 25 hours of recording time. However, automotive EDRs are not “black boxes;” they are much different, as they do not currently have the capability to record audio and record much less data than more sophisticated flight data recorders. Passenger vehicle EDRs typically capture data for seconds, not hours, leading up to a collision.  

EDRs have been around since the mid-1990s, but the Code of Federal Regulations (CFR) Part 563 that pertains to passenger vehicle EDRs became effective September 1, 2012. While an EDR is not required, most modern passenger vehicles have some form of event data recorder. If the manufacturer implements an EDR into a passenger vehicle, it must meet content and accuracy requirements put forth by CFR Part 563. According to CFR Part 563, the regulation “specifies uniform, national requirements for vehicles equipped with  event data recorders (EDRs) concerning the collection, storage, and retrievability of onboard motor vehicle crash   event  data.” Its purpose is to ensure that EDRs record useable data for effective crash investigations and for analyzing the performance of safety equipment like advanced restraint systems.

CFR Part 563 has requirements for data elements, data format, data capture, crash test performance and survivability, and for information that is included in a vehicle’s owner's manual. Required data elements include longitudinal change in velocity (delta-v), speed, safety belt status, and event completion. There are additional elements that are often recorded but are not required under Part 563 and include steering input, lateral delta-v, and vehicle roll angle among many others. 

While currently most passenger vehicles are equipped with EDR, this has historically not been the case. For example, BMWs did not start phasing in EDRs until 2013, whereas General Motors started in 1994. It is important to check with an accident reconstruction expert on whether or not the vehicle involved in the subject collision has an EDR.

Accessing EDRs 

Typically, EDR data is stored in the airbag control module, which is usually located near a vehicle’s center of gravity,  and can record data from various sensors located throughout the vehicle. The exact location in the vehicle and recording methods are left to the discretion of vehicle manufacturers, so knowing the year, make, and model is essential in any EDR data analysis. 

The data can be accessed through two methods: 1) a cable plugged into a port in the vehicle with power applied, or 2) by retrieving/removing the module if applying power to the vehicle is not possible or not safe. Vehicle-specific software is used to decode the data and provide a report. Explico’s qualified technicians can provide guidance on how data can be obtained for your specific vehicle.

The image above demonstrates how data from an EDR is accessed using Method #1, when a technician is able to apply power to the subject vehicle’s airbag module. The Bosch tool, the green box seen above, can be used to access data in most passenger vehicles.

The series of images above show an example of a time when accessing EDR data was not possible through the port in the vehicle, and Method #2 was used. The module was extracted from beneath the center consule and imaged, which is destructive to the vehicle, but not to the module if done correctly.

Although most passenger vehicles have an accessible EDR, each vehicle is different and needs to be assessed by a qualified technician prior to an inspection. Proper planning by a qualified technician is imperative; each data collection scenario is unique, and can require additional equipment and time depending on the status of the vehicle and module. To know if your vehicle has an EDR, contact Explico. We have the resources to let you know if your vehicle can potentially have useful data.

Commonly Asked Questions

Will EDR data be spoiled or permanently affected if it’s retrieved by a qualified technician?

No. EDR software only takes a copy of the data, therefore it is not altered in any way if the EDR is imaged appropriately. However, if a qualified technician is not used and the EDR is not imaged properly, there is a risk of evidence spoliation. 

How do I know if my event was recorded?

The only way to know for sure if your vehicle’s EDR recorded an event is to image the EDR and get the vehicle-specific report analyzed by a qualified analyst. CFR Part 563, which applies to passenger vehicles manufactured on or after September 1, 2012, that are equipped with an EDR, requires an event to be recorded if the vehicle experiences a change in velocity of 5 mph over a period of 150 milliseconds. However, older vehicles that are equipped with an EDR may have a different trigger threshold – each vehicle is different! 

Most EDRs do not record the date and time of an event. Therefore, if an event is recorded, it must be interpreted by comparison to  physical evidence and other incident information to determine if the event is related to the subject collision. 

How accurate are EDRs?

The accuracy of EDRs has been studied and published for years. Generally, EDR data is accurate, but needs to be interpreted properly. The reader is directed to Table 3 in CFR Part 563 for more specific information on the accuracy requirements put forth by the regulation. EDR data should always be used in conjunction with other generally-accepted accident reconstruction methods. Be sure to utilize a qualified EDR analyst to verify that the data recorded is not subject to any special circumstance.