Learn · Surveillance explained

What Are the Different Types of Surveillance Cameras?

Last updated: August 6, 2026

The five most common types of surveillance cameras are automatic license-plate readers (ALPR) such as Flock Safety cameras, CCTV video cameras, red-light cameras, speed cameras, and gunshot-detection sensors like ShotSpotter. Each is triggered differently, captures different data, and is run by a different mix of police, cities, and private operators, and only some are built to track your movements over time. This guide defines each type, explains how it works and what it records, and shows how Peripheri surfaces all of them in one alert layer.

Automatic license-plate readers (ALPR / Flock)

An automatic license-plate reader (ALPR) is a camera plus software that photographs every passing vehicle, reads the plate characters, converts them into searchable text, and stamps the record with the time and location. Modern systems, Flock Safety being the largest US vendor, also derive a "vehicle fingerprint": make, model, color, and features like roof racks or bumper stickers. Because the cameras are networked, individual sightings combine into a travel history showing where a vehicle has been across a city or, through data-sharing, the country. ALPRs are operated by police departments, but also by homeowners' associations and businesses that can share their feeds with law enforcement. The privacy implication is the sharpest of any camera type here: mass plate collection lets operators reconstruct the movements of ordinary people who are not suspected of any crime. For a deep dive, see our guide on what a Flock camera is.

CCTV (closed-circuit television)

CCTV (closed-circuit television) is a system of fixed video cameras that continuously monitor a place and feed to a private, "closed" set of monitors or recorders rather than being broadcast publicly. A CCTV camera works by recording general video of whatever is in its field of view, meaning people, storefronts, doorways, and streets, typically around the clock. Unlike ALPR, it is not designed to read plates or track vehicles; it captures scenes. CCTV is run by an enormous range of operators: city governments, transit agencies, retailers, offices, and individual homeowners with doorbell and security cameras. The privacy implication is breadth and normalization: cameras are everywhere. A growing concern is that modern CCTV increasingly layers on analytics such as facial recognition, license-plate reading, or object detection, blurring the line between passive recording and active identification.

Red-light cameras

A red-light camera is an automated enforcement camera at an intersection that photographs vehicles entering after the signal has turned red. Sensors buried in the pavement or radar detect a vehicle crossing the stop line on red; the system then captures still images or video of the vehicle and its license plate, and the record is reviewed to issue an automated citation to the registered owner. Red-light cameras are run by city and state transportation departments, often through a private vendor that operates the hardware and processes tickets. The privacy implication is narrower than ALPR: a red-light camera records only at the moment of a claimed violation at one fixed intersection, so it is not designed to track continuous movement, though the citations it generates are still a record of where and when a specific vehicle was.

Speed cameras

A speed camera is an automated enforcement camera that measures a vehicle's speed and captures its plate when the vehicle exceeds the posted limit. It works using radar, lidar, or induction loops in the road to clock the speed; a "point" speed camera measures your speed at a single spot, while an "average-speed" (or point-to-point) system reads your plate at two locations and calculates your average speed over the distance between them. Like red-light cameras, speed cameras are run by transportation authorities, frequently via private contractors. The privacy implication sits between the others: most speed cameras are single-event enforcement tools, but average-speed corridors necessarily log a vehicle at two points and times, which is a limited form of movement tracking.

Gunshot-detection sensors (ShotSpotter)

A gunshot-detection sensor is not a camera at all but an acoustic device. The best-known system is ShotSpotter, now sold as SoundThinking. Networks of microphones are mounted on poles and rooftops across a coverage area; when they pick up a loud, impulsive sound, software triangulates the location of suspected gunfire from the time each sensor heard it and alerts police, often within seconds. It captures audio and a computed location rather than plates or faces, and it is deployed and paid for by city police departments. The privacy implication is distinct: because the sensors are always listening, civil-liberties groups have raised concerns about incidental audio capture, and independent audits have questioned the technology's accuracy and its concentration in specific neighborhoods. Peripheri maps these sensors so you know where the surveillance infrastructure is, whatever form it takes.

Surveillance camera types compared

The clearest way to tell these five apart is by three questions: what sets each one off, what it actually records, and whether it is built to follow your movement over time.

Type	What triggers it	What it records	Tracks movement over time?
ALPR / Flock	Any passing vehicle	Plate, vehicle fingerprint, time, location	Yes, it logs movement across a network over time
CCTV	Continuous recording	General video of people and places	Only within its field of view
Red-light camera	Entering an intersection on red	Photo/video of the violating vehicle and plate	No, single-event capture
Speed camera	Exceeding the posted speed limit	Speed reading, photo of vehicle and plate	Sometimes, average-speed cameras span two points
Gunshot sensor (ShotSpotter)	Loud impulsive sound (suspected gunfire)	Audio and triangulated location, not images	No, it tracks sound events, not people

How Peripheri shows you all of them

Most tools focus on a single category: a red-light-camera map here, a Flock tracker there. Peripheri is the only consumer app that combines every one of these types into a single awareness layer. Peripheri is a privacy-first iOS app that alerts you when you're near surveillance cameras, including Flock Safety ALPR license-plate readers, red-light and speed cameras, CCTV, and gunshot-detection sensors, with everything computed on your device so your location never leaves your phone. Open the map to see every known Flock ALPR reader, CCTV camera, red-light and speed camera, and gunshot sensor around you, each color-coded by type; switch to the live directional radar to feel their distance and bearing as you move; and turn on protection to get a discreet proximity alert, plus a glanceable ring on your Lock Screen and Dynamic Island, the moment you approach one. Because the matching runs entirely on your iPhone, you get the full picture without handing your location to anyone. You can read exactly how that works in our privacy policy.

Get Peripheri

Frequently asked questions

What are the main types of surveillance cameras?

The five most common types are automatic license-plate readers (ALPR, including Flock Safety cameras), CCTV video cameras, red-light cameras, speed cameras, and gunshot-detection sensors like ShotSpotter. ALPR reads and logs license plates; CCTV records general video; red-light and speed cameras enforce specific traffic laws; and gunshot sensors are acoustic devices that detect and locate the sound of gunfire rather than capture images.

What is the difference between a red-light camera and a speed camera?

A red-light camera is triggered by a vehicle entering an intersection after the signal turns red and photographs that violation to issue a citation. A speed camera is triggered by a vehicle exceeding the posted limit (measured by radar, lidar, or induction loops) and captures the plate to enforce speeding. Red-light cameras watch a single intersection; speed cameras watch a stretch of road, sometimes measuring average speed between two points.

What is CCTV?

CCTV (closed-circuit television) is a system of fixed video cameras that continuously monitor a location and feed to a private, closed set of monitors or recorders. Unlike ALPR, CCTV records general video of people and places rather than reading license plates, though many modern CCTV systems now add analytics such as facial recognition or object detection. It is run by governments, businesses, and homeowners.

What is ShotSpotter?

ShotSpotter, now sold under the name SoundThinking, is a gunshot-detection system. Acoustic sensors mounted on poles and rooftops listen for loud impulsive sounds, triangulate the location of suspected gunfire, and alert police. Unlike the other camera types it does not photograph plates or faces; it captures audio. Studies and audits have questioned its accuracy and its effect on policing in the neighborhoods where it is deployed.

Do all surveillance cameras track your movements?

No. ALPR networks are specifically designed to track vehicle movement over time by logging plate, place, and timestamp, so combined detections reveal where a car has been. Red-light and speed cameras record only at the moment of a violation and are not built to track continuous movement. CCTV records where it is pointed but does not by itself follow a vehicle across a city, and gunshot sensors track sound events, not people.

Can one app show all these camera types?

Yes. Peripheri is an iPhone app that maps Flock ALPR readers, other license-plate readers, red-light and speed cameras, CCTV, and gunshot-detection sensors in a single alert layer, each color-coded by type. It alerts you as you approach any of them, and because the matching runs entirely on your device, your location never leaves your phone.