Expectations From Security Cameras

Set Realistic Expectations

Some people think that Neighborhood security surveillance is a silver bullet that will solve all problems related to crime. It is not, it is but one step in a neighborhood crime fighting initiative.

What to expect in regards to Prevention

Visible signs of Security Camera activity, such as signs and visible cameras, has a measurable preventive effect on premeditated crimes like burglary, robbery and theft, but has absolutely no preventive effect on crimes of passion like public drunkenness and fights.

Video Surveillance improves crime solving rates under certain circumstances.

Example of incorrect use of surveillance cameras.

The public surveillance cameras Tiburon, Ca, installed February 2010, has only contributed slightly to crime solving, the main problem being that the cameras are placed in High traffic areas. Specifically the problem is that when examining cameras recordings, the suspect pool becomes too big to of any practical use.

Quiet neighborhood streets are perfect

Low traffic areas or areas with low traffic of suspects have a better chance of isolating suspects and therefore solving the crimes. The quiet suburban street – a burglar favorite – is also the place that has the best return of investment for a neighborhood camera solution, especially when combined with individual alarm systems.

Does footage always lead to conviction? 

No – most of the video produced will be considered circumstantial evidence, e.g. images of  the suspect entering and/or leaving the neighborhood around the time of the crime, will help in the investigation and together with other pieces of evidence will lead to a conviction.

What footage is needed for Conviction.

In order to get a burglary conviction based on surveillance video alone the video will need to have all of the following:

  1. 100% certain identification: i.e. clear unmasked face shoot
  2. The breaking and entering.
  3. The suspect leaving with items of value that are clearly identifiable.
  4. Clear chain of evidence of the footage.
  5. Timestamp on the video
  6. Video obtained without violating the suspects constitutional rights. (see article on legal considerations)

Example of footage not enough for conviction alone.

The following photos is not enough to convict by itself.

  1. Suspect arriving on the street, license plate readable
  2. Suspect entering the driveway of victim
  3. Suspect leaving the driveway of victim 10 minutes later.

It is however enough for an investigator to pay a visit to the suspect, and if we are lucky the suspect is on probation or parole letting any peace officer in California perform a warrantless and suspicionless search and seizure.

If the same vehicle and person has been linked to other burglaries it could be enough for a search warrant and/or an arrest.


Don’t expect that the police can rush out and make an arrest based on your video surveillance, do expect that submitting your video to the police could be the lead that changes a case from unsolvable to solvable leading to apprehension of the criminals.

Don't expect the Police to make an arrest based on your images alone. Actual Camera recording of Police Car at 3:00 am with one of our Cameras, click to zoom in and read the license plate.

Additional reading

Parole and Probation searches – Article – Police Magazine

Traffic Count and Statistics.

Cute little garbage truck captured in the fog, one of 8 passings of garbage trucks that day.

Our Neighborhood Security Surveillance Camera records a lot of traffic but how many passers-by do we really record:

I decided to pick 1 day and do a detailed count, this happened to coincide with a theft from a car that night which allowed me to combine the work.

in 24 hours, the motion detector recorded 491 sequences of events on 1 camera covering an entrance to our neighborhood.
The count below records objects passing the camera, not unique cars passing, e.g. the same car coming and going will be counted as 2.
1 Bicycle
2 Motorcycles
3 Utility trucks
7 Delivery vans
8 Contractors
8 Garbage Trucks (garbage day, but I was surprised it was that many)
14 Pedestrians (with 6 dogs)
238 Passenger Cars
1 Suspicious Person (Photo and license plate submitted to Oakland Police)

Total of 281 relevant events.

The rest was false alarms on the motion sensor, e.g.  moving shadows from clouds, fog, changing light. (it was a foggy day)  e.g.

License plate readability
Of the 266 vehicles, 7 did not have a License plate. (2.6%)
Out of 259 vehicles with License plates 255 could be read by human(*) (98.5%)

(8) The human is me, method included selecting the best photo for each vehicle and using different zoom levels, sometimes part of the license plate could be read in one photo and the rest of the plate in another photo. No image manipulation was needed (such as Photoshop)

Room for Improvement
A motion detector False Positive rate of 42% – is too much.

While I would rather have too many recordings than missing 1 critical, here is room for improvements.
I am currently adjusting the sensitivity levels in order to try reduce the number of false recordings.