Cyberattack Disrupts Ignition Interlock Systems in the U.S., Leaving Thousands of Drivers Unable to Start Cars

Drivers across the United States recently faced an unusual problem: their cars simply wouldn’t start. The issue stemmed from a malfunction involving ignition interlock devices made by Intoxalock, one of the largest providers of alcohol breath-test systems for vehicles in the country. The company later confirmed that the disruption was caused by a cyberattack that forced parts of its service network offline.

The trouble began in mid-March, when drivers started reporting that the breathalyzer systems installed in their vehicles had suddenly stopped functioning. These devices require drivers to blow into a breath tester before the engine can start. The technology is widely used in the U.S. for motorists who are legally required to prove sobriety before driving.

According to Intoxalock, the company temporarily shut down some internal services to protect staff and contain the security threat. The shutdown was intended as a precaution to prevent the cyber incident from spreading further through its network.

But the move had an unintended side effect. Because the system could no longer communicate properly with remote services, some ignition interlock devices could not complete required verification steps. Without confirmation from the unit, the engine remains locked. As a result, thousands of drivers across the country suddenly found themselves unable to start their vehicles, while service centers were also temporarily unable to process appointments.

The first complaints appeared on March 14. Drivers took to social media to report being stuck at home or unable to get to work. One user on Reddit wrote that his car locked up just after midnight, while another said he had to call a taxi to avoid missing a shift. Reports were particularly common in major cities such as Houston and Dallas.

Intoxalock later confirmed the cyberattack but did not disclose details about the nature of the incident. It remains unclear whether the breach involved ransomware, data theft, or another type of cyber intrusion. In a public statement, the company said that services related to the installation and maintenance of ignition interlock devices were temporarily postponed.

Customers were asked to reschedule appointments at service centers. The company also promised to reimburse drivers for towing expenses if their vehicles had to be transported during the outage once operations resumed.

On March 18, Intoxalock reported that many customers had missed required device calibrations and extended the service pause until March 22. By that date, service centers had returned to full operation and all breathalyzer functions were restored to normal. The company said both new installations and previously delayed appointments could proceed without restrictions.

The incident highlights a growing issue tied to the increasing digitalization of vehicles and automotive safety systems. Ignition interlock devices remain an effective tool in the fight against drunk driving. At the same time, their reliance on remote servers, software updates, and regular calibrations can leave drivers unexpectedly vulnerable to technical failures or cyber threats.

For drivers affected by the outage, Intoxalock advised contacting the company regarding reimbursement for towing costs and monitoring official updates as services return to normal.