In 2003, a sniper who struck repeatedly along a Columbus, Ohio, highway was apprehended with the help of gunshot-detection technology. Now, the same company that provided the technology to Columbus has been commissioned by the New Haven Police Department to install gunshot detectors in the Elm City.

The ShotSpotter Gunshot Location System detects gunfire and triangulates its position via a network of sensors, alerting 911 dispatchers and providing an audio clip of each event identified as gunfire. Although a spokesman for the NHPD declined to give any specifics on the location of the sensors, the Associated Press reported Sunday that they will be installed “on rooftops at strategic locations throughout the city’s Hill neighborhood to the Hamden town line.”

The city has commissioned 18 to 20 sensors, which, according to the producer ShotSpotter’s Web site, is enough to cover an area of approximately one square mile in total.

ShotSpotter technicians have already installed the system’s main hub; general sensor deployment will begin April 6. NHPD Assistant Chief of Investigations Peter Reichard said in an e-mail that the system will be installed by late spring and that testing will begin immediately afterward.

“It will take up to six months for the system to ‘learn’ what are actual gunshots in the area,” he said.

Police officers in Oakland, Calif., and Rochester, N.Y., highlighted the efficiency of the system as its main benefit.

“What we’ve noticed is that we’re able to effectively respond to gunshot calls in a more effective manner,” said officer Jeff Thomason of the Oakland Police Department, which has employed the system for five years. “There’s no delay in this system; there’s always a delay with dispatch when witnesses call it in.”

In general, he said, witness reports are nonspecific, typically spanning a wide area.

But Public Information Officer LaRon Singletary of the Rochester Police Department, which has been using ShotSpotter since 2006, said the technology is not perfect. In August 2008, the Boston Globe reported that ShotSpotter had misclassified hard rain and also had trouble penetrating the brick buildings of Boston.

However, as Singletary said, besides being efficient, ShotSpotter also reports incidents that the public will not.

“Sometimes the people hear a gunshot; they often do not call the police,” he said. “We’ve been through a homicide scene where sometimes no one will call the police, and due to ShotSpotter officers were able to go to the area.”

When asked, Singletary said Rochester has recently seen a decrease in firearm-related crimes. But, he said he is unsure whether ShotSpotter or other department initiatives are responsible.

In a press release two weeks ago, ShotSpotter President and CEO James Beldock pointed out other benefits of the technology. “System data paints an accurate and comprehensive picture of gunfire activity within their coverage area, unbiased by under-reporting trends common in areas of high gun violence,” he wrote. “Having this data has allowed deputies to analyze the magnitude of incidents within their coverage area and use this information to strengthen intelligence-led policing efforts already in progress.”

The ShotSpotter Web site also notes that because of the audio that the technology provides to dispatchers, police can identify beforehand what types of weapons they may face upon arrival.

Sometimes, however, ShotSpotter misses the mark.

“There have been opportunities where we have responded to certain instances, and fireworks have set it off — but that’s pretty much far and few between,” he said.

Aside from these instances, Singletary said the department has not had to deal with any other problems or complaints regarding the system.

A ShotSpotter warning gives the police certain latitude when they reach the alert area.

“Location of a gunfire incident by the system is only an investigatory tool and amounts to reasonable suspicion,” Reichard said.

Those under “reasonable suspicion” may legally be detained, questioned and frisked without being arrested, though an arrest can also follow if probable cause develops during this process.

When it was installed in Rochester, the system cost about $150,000 for the first square mile, but it was underwritten by a grant from the federal government. The same will happen in New Haven: “Initial cost to the city is $0,” Reichard wrote. Overall, one of the four goals of Mayor John DeStefano Jr.’s 2009-’10 budget proposal is violence reduction and public safety.

Despite other major city cutbacks, the NHPD will receive a 4.4-percent budget increase and will add a new class of 45 police officers to the force.