Cell Phone Forensics

A commercial truck driver’s cell phone is one of the most detailed witnesses to a crash.

It records what the driver was doing with the device (texting, calling, scrolling, navigating) down to the second. It logs GPS coordinates, connects to cell towers that place the phone along a route, and stores usage data from dozens of applications, many of which the driver may not realize are generating records. When a rear-end collision or lane-departure crash raises questions about driver distraction, the phone and the records surrounding it can answer those questions with a precision that eyewitness testimony cannot match.

Federal regulations already prohibit commercial motor vehicle drivers from texting or using hand-held mobile phones while driving.¹ The prohibition reflects research commissioned by the Federal Motor Carrier Safety Administration (“FMCSA”) showing that the odds of a safety-critical event (a crash, near-crash, or unintentional lane deviation) are roughly 23 times greater for commercial motor vehicle (“CMV”) drivers who text while driving and roughly 6 times greater for those who manually dial a phone.² Yet violations persist. In crash litigation, the question is not whether the regulations exist but whether the evidence to prove or disprove a violation has been preserved, extracted, and presented in a form that meets evidentiary standards.

The Federal Prohibition on Driver Cell Phone Use

Two federal regulations govern cell phone use by commercial motor vehicle drivers. Under 49 C.F.R. § 392.80, no driver may engage in texting while driving a CMV, and no motor carrier may allow or require its drivers to do so.³ Texting is defined broadly. It includes manually entering text into any electronic device, reading text from a device, sending or reading emails, instant messages, or web page requests, and pressing more than a single button to initiate or terminate a voice call.⁴

Under 49 C.F.R. § 392.82, no driver may use a hand-held mobile telephone while driving a CMV.⁵ Use of a hand-held mobile telephone means holding the phone to conduct a call, dialing by pressing more than a single button, or reaching for the phone in a manner that requires the driver to leave the normal seated driving position.⁶ Hands-free operation using a single-button earpiece or Bluetooth device mounted within arm’s reach is permitted. Both regulations define “driving” to include operating a CMV while temporarily stationary because of traffic, a traffic control device, or other momentary delays, meaning a driver stopped at a red light is still subject to the prohibition.⁷

The penalties are substantial and are periodically adjusted for inflation. Drivers currently face civil penalties of up to $4,812 per violation, and motor carriers that allow or require prohibited phone use face fines of up to $19,246. A driver convicted of two serious traffic violations involving cell phone use within a three-year period faces a 60-day disqualification from operating a CMV. Three or more violations in three years results in a 120-day disqualification.⁸ Violations carry the maximum severity weight under FMCSA’s Safety Measurement System, directly impacting a carrier’s safety scores, insurance rates, and audit exposure.⁹

The regulatory framework matters in crash litigation for a specific reason: a violation of a federal safety regulation designed to protect the public can constitute negligence per se in many jurisdictions, meaning the plaintiff need not independently prove the driver acted unreasonably; the violation itself establishes the breach of the duty of care. Whether and how this doctrine applies varies by state, and counsel should confirm the specific formulation that governs in the jurisdiction where the case is filed.

What Cell Phone Records Contain

Cell phone evidence in truck crash litigation comes from three principal sources: wireless carrier records, forensic extraction of the device itself, and third-party application data.

Wireless carrier records are the most commonly subpoenaed form of cell phone evidence. They are maintained by the carrier (AT&T, Verizon, T-Mobile, and others) and include call detail records showing every inbound and outbound call with timestamps, duration, and the cell tower that handled the connection. They also include text message logs showing the time each message was sent or received, though carriers generally do not retain the content of text messages for extended periods.¹⁰ Data session records show when the phone connected to the carrier’s data network, which can indicate app usage, web browsing, or background data transfers.

Forensic extraction of the phone itself provides a far more granular picture. Using commercial forensic extraction tools, a qualified forensic examiner can perform a logical or physical extraction of the device, recovering active and deleted data including text messages, call logs, application usage history, GPS coordinates, photographs with embedded geolocation metadata, browser history, and screen-on and screen-off times.¹¹ A physical extraction, which copies the device’s memory at the bit level, can recover data the user believed was deleted, including text messages removed from the messaging app and cleared browser histories.

Third-party application data represents a growing category of evidence. Navigation apps such as Google Maps and Waze log route history and arrival times. Social media applications record posting times. Streaming services log playback activity. Ride-hailing and delivery apps, if present, may log driver speed and location. Each of these applications may store data both on the device and on the provider’s servers. Obtaining server-side data typically requires a separate subpoena directed to the application provider, because the carrier’s records will not capture the substance of app-level activity, only the data connection that supported it.

Cell Tower Evidence & Location Data

Cell tower records serve a distinct function from carrier call detail records. When a phone connects to the network (whether for a call, text, or data session), the carrier logs which cell tower handled the connection. Each tower covers a defined geographic area, and the tower identifier, combined with the sector of the tower’s antenna that was engaged, can place the phone within a general area at a specific time.

In truck crash cases, cell tower data is most useful for corroborating or contradicting a driver’s account of where they were at key moments. A driver who claims to have been stopped at a rest area at the time a call was placed, for example, can be tested against the tower records. If the call routed through a tower along the highway 30 miles from the rest area, the claim is undermined. Cell tower evidence does not provide GPS-level precision; it establishes that the phone was within the coverage area of a particular tower and sector, which in urban areas may be a few hundred meters and in rural areas may span several miles.

More precise location data may be available from the phone itself. GPS coordinates logged by navigation applications, photograph metadata, or the phone’s operating system location services can pinpoint the device’s location at specific times with substantially greater accuracy than cell tower records alone. Combining cell tower data with device-level GPS data and the truck’s own telematics or ELD records creates a multi-source location history that is difficult to dispute.

Preservation: The Critical First Step

Cell phone evidence is perishable. Phones get replaced, damaged, or reset. Wireless carriers purge records on their own retention schedules, and those schedules vary significantly by carrier and record type and are subject to change. One practitioner survey of major carriers’ compliance departments found meaningful variation: AT&T and Verizon reported retaining call detail records for around seven years, while T-Mobile reported retaining them for approximately two years; tower-location data tied to a Verizon call history was reported separately at roughly one rolling calendar year, while AT&T’s associated tower records were reported at the same seven-year window and T-Mobile’s at approximately two years. Text message content, as opposed to the log showing a message was sent, was reported as retained for only three to five days by the carriers that retain it at all; AT&T and T-Mobile reported not retaining text message content.¹² These figures come from carriers’ own informal representations to a forensic practitioner rather than published policy, and retention practices change; current retention for any specific carrier should be confirmed directly, ideally as part of the preservation letter and any follow-up subpoena.¹³ IP session logs and data usage records have their own, often shorter, retention windows.

The practical consequence is that evidence available in the first days after a crash may be permanently gone within weeks or months if no preservation steps are taken. A litigation hold letter sent to the opposing carrier, the driver, and the motor carrier should specifically identify the driver’s cell phone and any other personal electronic devices, the wireless carrier account, and any cloud-based accounts linked to the device.¹⁴ The hold should be sent as early as possible (ideally within days of the crash) and should request that the phone be powered down and stored in a manner that prevents remote wiping, automatic updates, or data overwriting.

Under Federal Rule of Civil Procedure 37(e), a court has two distinct tools available when electronically stored information that should have been preserved is lost because a party failed to take reasonable steps to preserve it. If the loss causes prejudice to another party, the court may order measures no greater than necessary to cure that prejudice. Only if the court additionally finds that the party acted with intent to deprive another party of the information’s use may it go further and presume the information was unfavorable, instruct the jury it may or must make that presumption, or dismiss the action or enter a default judgment. Mere prejudice, without a finding of intent, does not by itself support an adverse inference instruction or a case-dispositive sanction.¹⁵ The duty to preserve attaches when litigation is reasonably anticipated, which in a serious truck crash is typically the moment the crash occurs. A motor carrier that routinely replaces driver phones or allows drivers to trade in devices without forensic imaging after a crash involving injuries or fatalities risks a finding that it failed to meet its preservation obligations.

Admissibility: Authentication & Federal Rules of Evidence

Cell phone evidence must be authenticated before it can be admitted at trial. Under Federal Rule of Evidence 901(a), the proponent must produce evidence sufficient to support a finding that the item is what the proponent claims it is.¹⁶ For cell phone forensic data, this typically requires testimony from the forensic examiner who performed the extraction, explaining the tools used, the extraction methodology, the chain of custody, and confirming that the data was not altered during the process.

Federal Rule of Evidence 901(b)(9) provides for authentication by evidence describing a process or system used to produce a result and showing that the process or system produces an accurate result.¹⁷ This is the rule most directly applicable to forensic extraction reports, as it allows authentication through testimony about the forensic software, the extraction process, and the reliability of the output.

Since December 2017, Federal Rules of Evidence 902(13) and 902(14) have provided for self-authentication of certain electronic evidence.¹⁸ Rule 902(13) covers records generated by an electronic process or system, authenticated by a certification from a qualified person. Rule 902(14) covers data copied from an electronic device, storage medium, or file, authenticated by a process of digital identification as shown by a qualified person’s certification.¹⁹ These rules can streamline the admission of forensic extraction reports by allowing a certified forensic examiner to provide a written certification rather than live testimony, provided the opposing party receives adequate pretrial notice.

Hearsay remains a separate hurdle. The records themselves (call logs, text messages, GPS data) must independently satisfy a hearsay exception or exclusion. Carrier business records may qualify under Federal Rule of Evidence 803(6) as records of a regularly conducted activity.²⁰ Statements within text messages, however, are evaluated on their own terms and may constitute party-opponent admissions under Rule 801(d)(2), present sense impressions under Rule 803(1), or may be offered for a non-hearsay purpose such as establishing the driver’s state of mind or the fact that the phone was in active use at a particular time.²¹

What Investigators Look For After a Crash

When distraction is suspected in a commercial truck crash, investigators pursue a specific sequence of evidence. The first priority is identifying and securing the driver’s phone. The phone should be seized or impounded as soon as practicable and stored in a Faraday bag or equivalent RF-shielding container to prevent remote access, automatic cloud synchronization, or remote wipe commands.²²

Once the phone is preserved, a forensic examiner conducts the extraction. The examiner generates a forensic image of the device and works from the copy rather than the original. The extraction report will document call and text activity timestamped to the second, application usage logs showing which apps were active and when, GPS coordinates recorded by the phone’s location services, screen-on and screen-off events, and any photographs or videos taken near the time of the crash with their embedded metadata.

The examiner’s report is then cross-referenced against other available evidence: the wireless carrier’s call detail records, the truck’s electronic logging device data, event data recorder information, GPS and telematics records, dashcam footage, and any available witness statements. The objective is to establish a unified timeline showing what the driver was doing on the phone in the seconds and minutes before the crash, and whether that activity coincided with the critical pre-impact period.

For crashes involving drivers who were not using a company-issued phone, the personal device adds a layer of complexity. The driver’s personal phone may be subject to Fourth Amendment protections in the criminal context, following the Supreme Court’s holding in Riley v. California that police generally may not search a cell phone without a warrant.²³ In the civil litigation context, the phone’s contents are discoverable under the Federal Rules of Civil Procedure, but a motion to compel may be necessary if the driver resists production, and the court will balance the relevance of the data against privacy concerns.²⁴ In Arnold & Itkin’s experience, a CMV driver’s text messages at the time of the trip have typically been found to be relevant enough for production.

The carrier’s own records are independently discoverable. A motor carrier’s policies regarding cell phone use, its training records on the FMCSA prohibitions, its monitoring of driver compliance, and any prior violations documented in the driver’s file are all relevant to whether the carrier exercised reasonable oversight. A carrier that had no cell phone policy, never trained its drivers on the federal prohibition, and never monitored compliance faces questions about whether it met its obligations under 49 C.F.R. § 392.80 and § 392.82, both of which impose duties on the motor carrier, not just the driver.

Sources

• [1] 49 C.F.R. § 392.80; 49 C.F.R. § 392.82
• [2] FMCSA/Virginia Tech Transportation Institute, Driver Distraction in Commercial Vehicle Operations
• [3] 49 C.F.R. § 392.80(a)-(b)
• [4] 49 C.F.R. § 390.5T
• [5] 49 C.F.R. § 392.82(a)
• [6] 49 C.F.R. § 390.5T
• [7] 49 C.F.R. § 392.80(c); 49 C.F.R. § 392.82(b)
• [8] 49 C.F.R. § 383.51(c), Table 2; 49 C.F.R. Part 386, Appendix B; FMCSA, Mobile Phone Restrictions Fact Sheet
• [9] FMCSA, Distracted Driving
• [10] Patrick Siewert, Cellular Provider Record Retention Periods, Forensic Focus 
• [11] NIST Special Publication 800-101 Rev. 1, Guidelines on Mobile Device Forensics 
• [12] Patrick Siewert, Cellular Provider Record Retention Periods, Forensic Focus 
• [13] Id
• [14] Fed. R. Civ. P. 37(e) Advisory Committee Note
• [15] Fed. R. Civ. P. 37(e)(1)-(2)
• [16] Fed. R. Evid. 901(a)
• [17] Fed. R. Evid. 901(b)(9)
• [18] Fed. R. Evid. 902(13)-(14)
• [19] American Bar Association, New Rules for Self-Authenticating Electronic Evidence.
• [20] Fed. R. Evid. 803(6)
• [21] Fed. R. Evid. 801(d)(2); Fed. R. Evid. 803(1)
• [22] NIST Special Publication 800-101 Rev. 1, Guidelines on Mobile Device Forensics
• [23] Riley v. California, 573 U.S. 373
• [24] Fed. R. Civ. P. 26(b)(1)