How Black Box Data Helps in Truck Accident Litigation

Many truck accidents lead to injury claims from people hurt in the crash. Black box data can be important evidence in a truck accident claim because it may show if a truck driver or trucking company caused the crash by failing to safely operate or maintain the truck.

What Is Black Box Data, and What Does It Record?

Commercial trucks carry several electronic systems that together function as a “black box”:

• The Engine Control Module (ECM) continuously monitors engine and vehicle performance.
• Event Data Recorders (EDRs) capture the seconds surrounding a sudden event like a hard brake or collision.
• Electronic Logging Devices (ELDs) track a driver’s hours behind the wheel.

Depending on the system, recorded data may show the truck’s speed, engine activity, braking, cruise control use, seatbelt use, location, sudden stops, problems with the vehicle, and driving time¹.

Federal law requires most commercial drivers to use ELDs². The FMCSA and California track these records³ to help monitor driving hours and prevent tired driving. ECM data is also common in modern trucks, and the National Highway Traffic Safety Administration (NHTSA) regulates EDRs when they are installed.⁴

How Black Box Data Can Provide Evidence of Negligence

Black box data can be some of the strongest evidence in a truck accident claim. It provides a record of what the truck was doing at the time of the crash.

This data frequently reveals:

• Speeding – Recorded speed can show the truck was traveling faster than the limit or too fast for conditions.
• Driver fatigue – ELD records can expose hours-of-service violations, such as driving past the 11-hour daily limit.
• Failure to brake – Brake and throttle data can show a driver never slowed before a rear-end collision.
• Distraction or delayed reaction – The absence of any evasive input in the seconds before impact can indicate distracted driving.

These violations tie directly to federal safety rules, meaning black box data after a truck accident can establish that a driver or carrier broke the law. In a truck accident claim, violations of safety rules can amount to negligence per se⁵, which means the truck driver or trucking company is presumed negligent. The injured victim only has to show that the safety violations/negligence caused their crash and injuries.

Accessing Black Box Data

Under California Vehicle Code § 9951⁶, data from a vehicle’s EDR generally belongs to the vehicle owner. Someone else may only download or access this data in limited situations:

• With the owner’s consent
• Under a court order or subpoena
• By a licensed technician or dealer for servicing or diagnosing the vehicle (with owner consent)
• For traffic safety research, provided the data is stripped of identifying information
• To determine the need for or facilitate emergency medical response after a crash

ECM data can be overwritten once the truck is driven again or serviced, sometimes within days. FMCSA rules only require carriers to retain ELD records for six months.

A truck accident attorney can send a spoliation or preservation letter soon after a crash to help protect important black box data and ensure it can be collected and used in an injury claim.

If you or a loved one was involved in a truck accident and have questions about getting black box data from the trucking company, contact Curtis Legal Group today to schedule a Free Consultation.

Sources:

¹https://www.fmcsa.dot.gov/safety/data-and-statistics/large-truck-and-bus-crash-facts

²https://www.ecfr.gov/current/title-49/subtitle-B/chapter-III/subchapter-B/part-395

³https://govt.westlaw.com/calregs/Browse/Home/California/CaliforniaCodeofRegulations?guid=I4CE8D9D05A1E11EC8227000D3A7C4BC3&transitionType=Default&contextData=%28sc.Default%29

⁴https://www.ecfr.gov/current/title-49/subtitle-B/chapter-V/part-563

⁵https://www.law.cornell.edu/wex/negligence_per_se

⁶https://law.justia.com/codes/california/code-veh/division-3-6/chapter-1/section-9951/