How automatic license plate readers contributed to one town's drop in crime

The ALPR deployment in Tiburon (Calif.) offers quite a few compelling pieces of information which can be of great benefit to other departments across the country

A couple of days ago, I posted an item highlighting a few suggested best practices when installing a static-mounted automatic license plate recognition system.

To illustrate their effectiveness, I drew upon my memory of when the town of Tiburon installed ALPRs from PIPS Technology on the only two roadways into and out of the San Francisco suburb of 8,500 residents.

I speculated — quite correctly, apparently — that the installation significantly reduced the number of crimes being perpetrated by non-residents “commuting to ‘work’ in affluent neighborhoods.” Well, yesterday I had the pleasure of speaking with Tiburon Chief of Police Michael Cronin, who confirmed those suspicions.

Solid Results, Substantial ROI
“The system’s been up and operational now for about a year and a half, and we think it’s been very effective,” Chief Cronin told me.

“One of the crimes we specifically targeted was larceny, which declined from 128 in 2008 to 78 in 2011. Part one crime has declined 34 percent, and we’re pretty pleased with those numbers particularly when we compare them to surrounding jurisdictions whose crime has remained flat or gone up.”

The first full year of operation for the new ALPR system, which became operational in the late fall of 2010, was calendar year 2011, so that precipitous drop of 50 fewer larcenies in a three-year span can only partially be attributed to the new system.

Even with that said, it’s well worth mentioning that unless a violator wants to walk into and out of their crime scene in Tiburon, those ALPRs will record their movement.

Considering the sheer volume of publicity the installation of the system received — not just locally but across the country — it’s safe to assume that a certain number of criminals simply decided to stay away.

In a January 2012 report Chief Cronin submitted to the Tiburon Town Manager, Cronin stated that while it “is impossible to say with certainty that the ALPRS system was solely responsible [for the drop in crime] I believe it is fair to assume it had an impact. The publicity that attended system acquisition may have played a greater deterrent role than we anticipated.”

During our brief phone conversation yesterday, Chief Cronin elaborated somewhat on that point. “We had a guy here who we detained in some other crime and we were talking to him about a burglary here and he said, ‘I don’t do none of that here—you people got all those cameras.’ They have some sort of a vague idea that we have cameras all over the place, and I’m not too interested in disabusing them of that notion.”

Although the deterrence capability of the system cannot be totally, objectively measured, there are some numbers which are as solid as the rocks that line Tiburon’s marina on the bay.

That same report stated that there were 27 inquiries made in the system in 2011, which resulted in identification of suspects in 11 separate cases and the recovery of four stolen vehicles.

Tiburon being Tiburon, the dollar value of those four cars can safely be assumed to be pretty substantial (in 2008, the theft of just two cars was valued at more than $200,000).

Speaking of dollar amounts, how much did Tiburon’s system cost during 2011? According to Chief Cronin’s report, the total annual cost of operation for the system for the year was just a shade more than $10,000.

Deployed Strategically, Used Selectively
Critics contend that these captured license plate numbers are retained ad infinitum, but in addition to police policy which defines precisely when the data is deleted, such retention is a practical impossibility. No PD in the country would want to forever be buying up data storage this would require.

As much as we can collectively delight in the misperception among uninformed criminals who believe that “you people got all those cameras” monitoring people’s every move, the facts are quite the opposite.

The effectiveness of such has nothing to do with “how many” cameras there are, but how well those assets are deployed. No matter how many fixed-base — or mobile, for that matter — ALPRs are set up in a given jurisdiction, the real key to success is how they’re integrated into the investigative process.

For example, police agencies can determine a fairly narrow timeframe within which a crime has occurred — typically just a couple of hours — and knowing where the crime has occurred often suggests a limited number of routes the violator might have used to egress the area. Mining the database of “captured” license plates becomes a very clearly-defined exercise.

Sure, Tiburon is unique in that there are just two roads into town, but there are many cities and towns with somewhat limited access points. There are even more places where there may be dozens of streets which cross the border, but just two which see any appreciable traffic.

The point is, when an agency is contemplating the purchase of such a system, it has to take a system-wide view.

“All I know is my crime rate went down,” Chief Cronin concluded. With a bit of laughter in his voice, he added, “Now, I actually believe that that’s inspired leadership of the police department, but you know, other people might think it was the cameras.”

In my opinion, both of those factors, in conjunction with some outstanding work by the 13 sworn LEOs keeping Tiburon safe on a daily basis, is probably closer to the truth. 

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