When a serious trucking crash happens on South Carolina roads—from I95 and I26 to rural two lanes—the most powerful evidence may be inside the tractor itself: the engine control module (ECM) or event data recorder (EDR). Used properly, this data can corroborate physical evidence, clarify timelines, and rebut inaccurate narratives.
Below is a practical guide tailored to South Carolina law and procedure.
Passenger vehicles often store crash data in a dedicated EDR integrated with the airbag control module. Heavy commercial vehicles are different. Most tractors store operational snapshots in the ECM (sometimes called a heavy-vehicle EDR or HVEDR). Many fleets also run Electronic Logging Devices (ELDs) and separate telematics platforms. These systems are distinct:
Key takeaway: Do not assume tractor data looks like passenger-car crash data. Identify and pursue all three sources—ECM, ELD, and telematics/cameras.
HVEDRs typically record vehicle speed, brake usage, and diagnostic trouble codes. More specifically:
In South Carolina, an injured person can recover as long as their fault does not exceed 50%. Objective truck data often reduces disputed fault percentages by showing excess speed, delayed braking, or non-compliance—directly impacting apportionment and damages.
Example: If a jury finds the plaintiff 20% at fault and the truck driver 80% at fault on $500,000 damages, the net recovery is $400,000. Without objective data, the defense may succeed in pushing the plaintiff’s share above 50%, eliminating recovery entirely.
Act fast. Some ECM records are overwritten by later operation; telematics vendors may purge data under short retention policies.
Send a comprehensive preservation letter (litigation hold) to the motor carrier and its insurer, identifying:
Follow with Rule 45 subpoenas and, once filed, Rule 34 requests specifying native formats/metadata. Where appropriate, seek early protective orders/TROs to secure the truck and modules for inspection and imaging.
Wrongful death, medical malpractice, and other categories have additional rules—evaluate case-specific deadlines immediately.
South Carolina minimum auto limits: $25,000/$50,000 bodily injury and $25,000 property damage (25/50/25). Commercial motor carriers in interstate commerce typically carry much higher liability limits (often $750,000+; more for certain cargo/hazmat), so proving liability with hard data can materially affect settlement value.
Window
Practical Risk
Recommended Action
0–7 days
Truck towed/repaired; ECM snapshots overwritten by subsequent operation; short vendor retention for camera/telematics
Issue preservation letters and insurer notice immediately; request the truck be taken out of service until modules are imaged; ask the carrier to suspend autodeletion.
8–30 days
Some fleets auto-purge certain telematics/camera clips; ELD malfunction remediation deadlines can be misread
Follow up on the hold; request native exports from ELD/telematics; if resistance, file early suit and move for a preservation order.
≤ 6 months
Hours of service supporting documents must be retained by carriers for at least 6 months; delays risk loss of complementary HOS evidence
Serve Rule 34 requests specifying native formats/metadata; seek Rule 30(b)(6) on data systems and retention.
Up to 3 years
FMCSA accident register and required accident reports must be kept 3 years, but do not include ECM/EDR content
Request the register and all required accident reports; do not rely on this to capture ECM/EDR/telematics.
Heavy-truck data is manufacturer-specific. Retain experts who:
☐ Send a detailed preservation letter within days
☐ Seek consensual imaging or move quickly for a court order
☐ Demand native ECM/ELD/telematics exports and configuration files
☐ Notice a 30(b)(6) deposition on data systems and retention
☐ Establish airtight chain of custody and expert foundations
☐ Calendar the 3-year general PI SOL and any 2 or 3-year TCA deadlines
Objective truck data—properly preserved, extracted, and explained—can be outcome-determinative under South Carolina’s modified comparative negligence framework. Move fast, be specific about the sources you want, and build a record that survives admissibility challenges and persuades adjusters and juries alike.
For help preserving and using ECM/EDR, ELD, and telematics evidence in a South Carolina trucking case, contact Proffitt & Cox.
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Contingency fees are calculated based upon the gross amount recovered. Case costs paid by the firm are also reimbursed to the firm from the amount recovered. In most cases, the client will not be responsible for case costs if there is no recovery. Our agreement regarding fees and expenses applicable to your specific case will be provided in writing.
Any result our lawyers may have achieved on behalf of clients in other matters does not necessarily indicate similar results can be obtained for other clients. Each case must stand on its own merit based upon the facts and the law. Some cases referenced were handled by our attorneys while working at other firms, and in some cases, other lawyers participated in the representation of a client.
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