Guide · Injury · Chicago

Preserving Digital Evidence After a Chicago Crash

Video, vehicle data, phone records, and app data are deleted on schedules that have nothing to do with your claim. What to request, from whom, and when.

By Lincoln Square Law · 8-minute read

Much of the evidence in a modern crash case is not on the street. It sits on phones, in vehicle computers, on doorbell cameras, in rideshare and delivery apps, on city and transit video systems, and in the servers of companies that will overwrite it on a schedule that has nothing to do with your claim. Physical evidence at the scene can at least be photographed. Digital evidence often has to be requested from someone else, quickly and in the right form, or it is gone. This guide explains the main sources of digital evidence after a Chicago crash, how each is preserved, and the legal tools that apply.

Why digital evidence is different

Digital evidence has three features that make it both valuable and fragile. It is precise, recording times to the second and positions to within feet. It is usually controlled by someone other than the injured person, such as the other driver, a business, a carrier, or a government agency. And it is often deleted automatically: video systems loop, logs roll over, and app data is purged under retention policies. The practical consequence is that the first weeks after a crash matter more for digital evidence than for almost anything else.

Video: businesses, homes, and dashcams

• Private businesses. Gas stations, restaurants, and stores along the route often have exterior cameras. Many systems overwrite footage within days or weeks. A written request to the business asking that footage from a specific time window be preserved should go out immediately, followed by a formal request or subpoena for a copy.
• Doorbell and home cameras. Residents near the scene may have doorbell or security cameras. They are not required to share footage, but many will if asked promptly and politely, and they may agree to save it until it can be collected.
• Dashcams. Commercial vehicles, rideshare drivers, and many private drivers use dashcams. The other driver’s dashcam footage should be specifically identified in a preservation letter.

Public video and records

• City and transit cameras. Cameras operated by the City of Chicago, the Chicago Transit Authority, and other public bodies may have captured the crash. Public records can be requested under the Illinois Freedom of Information Act (5 ILCS 140), subject to its exemptions, and retention periods for traffic and transit video can be short.
• Police body-worn cameras. Illinois law requires law enforcement agencies to retain body-worn camera recordings for a limited period, generally 90 days, unless a recording is flagged, for example because it involves an incident that may lead to litigation (50 ILCS 706/10-20). A prompt request, and a request that the recording be preserved, matters.
• 911 recordings and dispatch data. Calls and dispatch logs can establish timing and early descriptions of the crash, and they are subject to their own retention schedules.

Vehicle data

• Event data recorders. Most modern passenger vehicles have an event data recorder that captures speed, braking, throttle, and seatbelt use in the seconds around a crash. Federal standards govern what these devices record (49 C.F.R. Part 563), and the Driver Privacy Act of 2015 provides that the data belongs to the vehicle’s owner or lessee. The data is lost if the vehicle is repaired, salvaged, or crushed before it is downloaded.
• Telematics and infotainment systems. Many vehicles transmit location and driving data to the manufacturer or an insurer’s usage-based program, and infotainment systems may store phone connection and call logs.
• Commercial vehicle systems. Trucks and fleet vehicles often use electronic logging devices, GPS tracking, and forward-facing and driver-facing cameras. Motor carriers must keep records of duty status and supporting documents for a limited period (49 C.F.R. 395.8), and those records should be requested in the first preservation letter.

Phones and apps

Distracted driving is often the central question in a crash case. Illinois generally prohibits drivers from using a hand-held electronic communication device while driving, with limited exceptions (625 ILCS 5/12-610.2). Proof usually comes from carrier records showing calls, texts, and data sessions, and from the device itself.

• Carrier records. Carriers keep call and text logs for varying periods. They are typically obtained by subpoena after suit is filed, and a preservation request to the carrier can help keep them available.
• Message content. Federal law generally prohibits service providers from disclosing the contents of communications in response to a civil subpoena (18 U.S.C. 2702). Content usually must come from the account holder or the device itself, through discovery.
• Rideshare and delivery apps. If a rideshare or delivery driver was involved, the company’s app data shows whether the driver was logged in, had accepted a trip, or was carrying a passenger, which can determine which insurance coverage applies. That data should be requested from the company early.

Why app status matters for coverage

For rideshare crashes, the app data is not just evidence of what happened. It decides which insurance applies. Illinois’ Transportation Network Providers Act sets different minimum coverage depending on whether the driver was logged into the app and waiting for a request, or had accepted a trip or was carrying a passenger (625 ILCS 57/10). The driver’s personal insurer may deny coverage for commercial activity, and the company’s policy may apply only in certain periods. A timestamped record of the driver’s app status at the moment of the crash, obtained from the company, is therefore often the most important document in the coverage dispute. The provision is currently scheduled for repeal in 2028, so check the text in effect on the date of the crash.

Your own digital evidence

The same rules apply to you. Your phone, your fitness tracker, your car’s data, and your social media accounts may all be requested by the defense. Do not delete anything. Keep your phone, save photographs and messages from the day of the crash, and avoid posting about the crash or your activities. Deleting data after a claim is foreseeable can lead to sanctions and damage your credibility, even if the deleted material was harmless.

The legal tools

• Preservation letters. A specific written demand, sent early, identifies the evidence, the time window, and the person or company holding it. Illinois does not impose a general duty to preserve evidence, but a duty can arise from an agreement, a contract, a statute, or another special circumstance, and a clear request helps establish that the holder knew the evidence was relevant to a foreseeable claim (Martin v. Keeley & Sons, Inc., 2012 IL 113270).
• Discovery. After suit is filed, Illinois discovery rules reach electronically stored information as well as paper documents (Ill. S. Ct. Rules 201 and 214). Courts consider proportionality and may enter protective orders for sensitive data.
• Subpoenas. Records held by nonparties, such as carriers, businesses, and app companies, can be obtained by subpoena, including subpoenas for records only.
• Sanctions. When evidence is lost after a party should have preserved it, a court may impose sanctions, including sanctions for destruction that occurred before suit was filed (Shimanovsky v. General Motors Corp., 181 Ill. 2d 112 (1998), applying Ill. S. Ct. R. 219(c)).

A practical sequence

• Within days: identify cameras along the route, send preservation requests to businesses, request public records and body-worn camera preservation, and secure the vehicles.
• Within weeks: send detailed preservation letters to the other driver, their insurer, employers, fleet operators, and app companies, and arrange for vehicle data downloads.
• After filing: serve subpoenas and discovery requests for carrier records, app data, and electronically stored information, and address any gaps promptly with the court.

Identify the sources early and request preservation in writing

Digital evidence can answer the questions that decide a crash case: how fast, who was looking at a phone, whether a light was red, whether a driver was on the clock. It is also the evidence most likely to disappear on a timer. Identifying the sources early and putting preservation requests in writing is what keeps it available when it is needed.