Last Updated: January 22, 2026
When Were Car Alarms Invented?
Car alarms are often traced to a 1913 theft-deterrent alarm story (a manually armed device credited to an unknown Denver prisoner), but early “alarm-like” anti-theft systems also included patents that mixed signaling + immobilizing functions.
A key early patent milestone is an Automobile-Theft Preventer filed March 5, 1918, and patented April 8, 1919, by St. George Evans and Edward B. Birkenbeuel, describing automatic signaling and disabling the ignition circuit.
A major aftermarket milestone is a patented “automatic burglar alarm for automobiles” system in 1954 (Victor Helman is commonly cited in summaries of mass-produced aftermarket alarms).
Timeline (Easy to Quote)
Year 1913
- What changed: A widely cited early “car alarm” origin story describes a manually armed alarm that triggered when someone tried to crank the engine.
- Why it matters: Often referenced as an early audible theft-deterrent concept, even though sources describe it as rudimentary.
Year 1918–1919
- What changed: Evans & Birkenbeuel filed (1918) and received a patent (1919) for an “Automobile-Theft Preventer” that could signal unauthorized movement and also lock open an electrical circuit so the car couldn’t run.
- Why it matters: This is strong primary evidence of an early alarm + immobilizer-style design, not just a noise maker.
Year 1954
- What changed: A patented “Automatic burglar alarm for automobiles” appears as a clear mid-century milestone tied to Victor Helman.
- Why it matters: Often cited as a big step toward practical, mass-market aftermarket alarm systems.
Year Early 1970s
- What changed: Factory (OEM) alarms started showing up, with Chrysler often mentioned among early major manufacturers offering them.
- Why it matters: Explains why many people remember alarms becoming “a real thing” later than the earliest inventions/patents.
Year 1980s–1990s
- What changed: Car alarms became far more common, but also gained a reputation for false alarms and being ignored.
- Why it matters: This changed public perception and pushed security toward immobilizers and better integrated systems.
What Counts As A Car alarm?
A car alarm is typically an electronic device installed in a vehicle to discourage theft by emitting a loud sound (and sometimes flashing lights) when triggered.
Car alarms aren’t the same as immobilizers, because an immobilizer’s main job is to prevent starting (often without making noise), while an alarm’s main job is to attract attention.
That difference is why “when were car alarms invented” can have multiple answers: some early systems focused on disabling ignition circuits (immobilizer-like), while others focused on audible deterrence.
Aftermarket vs Factory-Installed (OEM)
Car alarms are commonly grouped into OEM (factory) and aftermarket (added later).
So, one timeline can be about the earliest concepts/patents, and another timeline can be about when alarms became common on new cars from the factory.
Key Inventors and Early Patents (and Why Sources Disagree)
The 1913 “first car alarm” Story (Audible Deterrent)
A commonly repeated early account says an unknown Denver prisoner invented a manually armed alarm in 1913 that triggered during an attempted crank-start.
This is often treated as an “origin story” because it matches what many people imagine a car alarm to be: make noise and scare thieves.
Evans & Birkenbeuel (1918 Filing / 1919 Patent)
US1300150A (“Automobile-theft preventer”) lists inventors St. George Evans and Edward B. Birkenbeuel and shows an application filing date of March 5, 1918, and a patent date of April 8, 1919.
The patent describes both automatically signaling an unauthorized attempt to move a car and locking open an electric circuit so it’s impossible to move the car “by its own power.” This matters because it blurs the line between “alarm” and “immobilizer,” which is exactly why different websites give different “first” dates.
Victor Helman (1954 Patent Milestone)
Google Patents lists a 1954 patent for “Automatic burglar alarm for automobiles” associated with V. Helman (patented Aug. 24, 1954). Many historical summaries describe this period as a key step toward more widely adopted aftermarket alarms (more standardized, more sellable, more installable).
When Did Car Alarms Become Common?
Some sources point to factory (OEM) alarms appearing in the early 1970s, which is why drivers often associate “normal car alarms” with late-20th-century vehicles rather than the early 1900s. By the 1980s and 1990s, installation rose dramatically, and the public also became used to hearing alarms that were accidentally triggered and often ignored.
Why Do Car Alarms Go Off (and Are They Effective)?
Car alarms can trigger from door/trunk/hood monitoring, ignition changes, shock sensors, motion sensors, and other inputs, depending on OEM vs aftermarket design. However, car alarms have long been criticized for false triggers, and Wikipedia notes their sound-only deterrent effect can be limited because people often ignore them.
FAQs about when car alarms were invented
What year was the first car alarm invented?
A widely cited early answer is 1913, based on an origin story about a manually armed theft-deterrent alarm credited to an unknown Denver prisoner.
A stronger “paper trail” answer for early anti-theft alarm/immobilizer tech is the 1918 filing / 1919 patent for US1300150A by Evans and Birkenbeuel.
Who invented the car alarm?
There isn’t one single inventor because “car alarm” can mean different things across eras (audible alarms vs combined immobilizer/alarm systems).
A 1919 patent milestone is credited to St. George Evans and Edward B. Birkenbeuel for an automobile-theft preventer that includes signaling and immobilizing functions.
What was patented in 1919 related to car theft prevention?
US1300150A (“Automobile-Theft Preventer”) was patented April 8, 1919, and it describes automatic signaling of unauthorized movement, plus disabling an electrical circuit so the car can’t operate.
What’s the difference between an alarm and an immobilizer?
An alarm focuses on audible/visible deterrence (noise, lights), while an immobilizer focuses on preventing the engine from starting, often without drawing attention.
This difference is why some “first car alarm” timelines highlight 1913, while others highlight patents that include immobilizer behavior (1918–1919).
When was the first mass-produced aftermarket car alarm?
Many summaries point to a 1954 patented aftermarket milestone tied to Victor Helman’s “automatic burglar alarm for automobiles.”
Are modern car alarms better than early systems?
Modern alarms typically combine multiple sensors and can be integrated into broader vehicle security (OEM designs, key systems, and sometimes immobilizer behavior), unlike early manually armed concepts. Even so, the long-standing issue of false alarms has shaped how people respond to alarms in public settings.
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