The crash at first seemed like a routine fender-bender. One afternoon in late September, a retired teacher driving a new SUV was rear-ended at a quiet intersection in Algiers. When the 71-year-old woman got out to survey the damage, however, it became clear this was no accident.

A man emerged from the other vehicle and climbed into the woman’s 2015 Toyota RAV4. Startled, the victim tried to open the door but retreated after the carjacker “mumbled something about having a gun,” according to a police report.

The robber drove off in her SUV, stranding the woman without her purse. His accomplice, who had remained in the car that caused the crash, also left the scene.

Carjackings are proliferating at a staggering rate in New Orleans — a spike that has created yet another public safety challenge for a Police Department struggling to combat violent crime.

Analysts are at a loss to explain the increase, which has been particularly pronounced in the city’s poorer neighborhoods.

“There’s a criminal element here that seems to just enjoy instilling fear and making people uncomfortable,” said John Penny, a criminologist at Southern University at New Orleans.

The rate of carjackings in the city remained fairly steady between 2010 and 2013, even falling slightly during that four-year stretch. But last year, the number of cases skyrocketed by 87 percent, and this year, they are on pace to increase another 58 percent on top of that.

Carjackings are listed in the New Orleans Police Department’s daily bulletin of major offenses. The crime is often overshadowed by a steady drumbeat of murders and shootings. But stickups in general have been on the rise the past couple of years.

“Armed robberies and carjackings have not gotten a ton of publicity,” said Jeff Asher, a former city analyst who tracks local crime statistics and writes a blog for The New Orleans Advocate. “But something bad is happening.”

Police investigated 53 carjackings in 2013. This year’s tally stood at 145 as of Saturday morning, according to the NOPD.

More than two dozen carjackings were reported in the city last month, the vast majority of them during the nighttime hours.

As recently as Friday evening, a carjacker accosted a 48-year-old woman in Treme, pointed a weapon at her head and demanded her keys. Police said the woman resisted and was struck in the head several times before the man made off in her vehicle.

It’s difficult to determine whether carjackings are on the rise around the country, in part because the FBI’s Uniform Crime Reporting program does not count the crime separately from other robberies. But there is at least anecdotal evidence that suggests carjackings have become more prevalent amid the growing sophistication of anti-theft systems found in cars, particularly newer ones, said Roger Morris, vice president and spokesman for the National Insurance Crime Bureau.

Morris noted in an interview that vehicle thefts nationwide plummeted from an all-time high of 1.6 million in 1991 to about 700,000 in 2013 — in no small measure because of improvements in technology.

“Today’s cars are much harder to steal unless you’ve got the key,” Morris said. “You don’t just hot-wire a car and drive it away today. And one of the ways to access a car, unfortunately, is through carjacking.”

Bryan Lagarde, a former police officer who founded ProjectNOLA, a nonprofit that monitors a network of local crime cameras, said he believes the NOPD’s well-publicized manpower shortage may have emboldened criminals to commit relatively low-risk crimes like carjackings, which have notoriously low “solve” rates.

“I’m not talking about just less patrol officers but less detectives,” Lagarde said. “It used to be on our crime cameras that we’d see people running away from the scene of a crime. We don’t see that so much anymore. People seem to casually stroll away now.”

Asher, the crime analyst, said many New Orleans carjackings fit one of two patterns. In one scenario, the victim is stopped at a red light and is robbed at gunpoint of his wallet, cellphone and vehicle. Carjackers also frequently target drivers standing beside or near their vehicles, such as when they’re unloading groceries.

The New Orleans Advocate identified a handful of cases this year that closely resemble the Algiers carjacking that targeted the 71-year-old woman — a modus operandi some law enforcement agencies around the country have described as the “bump-and-run.”

A similar case happened in early April in West End. A 41-year-old man had stopped at the light at Veterans Boulevard and Fleur de Lis Drive when a Chevrolet Impala ran into his back bumper. When the man got out of his vehicle, a carjacker stepped out of the Impala and immediately pointed a gun at him while shouting profanities. The victim told police he had $2,000 in his trunk, along with an Apple laptop and a leather jacket.

Carjackings have afflicted many of the city’s neighborhoods, from the Lower 9th Ward to Mid-City. Uptown and Lakeview, however, have seen far fewer cases. The disparity is notable even for parts of town accustomed to seeing less violent crime than, say, the 7th Ward.

“With shootings, you see some spillover into other parts of the city,” said Asher, who plotted a map of this year’s carjackings. “But there appears to be a pretty huge geographic component with carjackings that I think defies easy explanation. It’s hard to say exactly what it means, but I think it’s stunning.”

Not all carjackings target new and shiny vehicles like the 2015 Toyota stolen in Algiers. Last month in New Orleans East, a 35-year-old man had just finished pumping gas into a 1997 Ford Taurus the police described as missing a hubcap and having “numerous dents throughout the body.”

A carjacker of short stature sneaked up behind him, held a gun to the man’s back and demanded he “drop the keys,” according to a police report. The victim complied and ran into the gas station.

The alleged carjacker, Kenneth “Hustle Man” Rodgers, was arrested last month and booked in connection with seven other armed robberies.

“We encourage people to never resist something like that over their car,” said Morris, the National Insurance Crime Bureau spokesman. “The car’s not worth a life.”

Follow Jim Mustian on Twitter, @JimMustian.