For teenagers who commit crimes in the District, stealing cars is out. Snatching smartphones directly from victims’ hands or breaking into their homes is in.

On average, juveniles were arrested for violent robberies or carjackings at least once a day last year, an almost 50 percent increase from 2007. During the same time, juvenile arrests for riding in stolen cars, a nonviolent crime, dropped by more than 60 percent.

The shift is one troubling indicator that the city’s youngest offenders are growing more aggressive and confrontational: Last year, teens made up 23 percent of all violent crime arrests, more than double the percentage in 2003.

“A number of years ago, car theft was off the scale. It was cool to get a car and joy ride,” said Daniel Okonkwo, executive director of DC Lawyers for Youth. “Now it’s an iPhone4, an iPod. Things you can’t afford when you don’t have money.”

Kip Patrick must have looked like he was a sure bet for having a smartphone in his pocket. He was wearing slacks and a button-down shirt as he walked alone near Ninth and U streets NW in the early morning of April 30 after finishing dinner and drinks.

As he walked by a group of youths, one of them suddenly shoved him, and he found himself rolling on the ground, scuffling with the guy.

“I got scraped up pretty good,” said Patrick, 38, who lives several blocks away.

When his BlackBerry Bold fell out of his pocket, someone in the group picked it up, and another youth pulled Patrick’s attacker off him. Then the whole group ran.

“I guess that’s D.C.,” said Patrick, who added that there had not been an arrest in the case. “But we can’t live in fear. If we do, D.C. isn’t a place anybody’s going to want to live.”

This year, juveniles account for 7 percent of overall arrests in the city — but about 45 percent of all arrests for robbery and carjacking, and 35 percent of burglary arrests, said D.C. Police Chief Cathy L. Lanier.

“They are overrepresented in those categories,” said Lanier, who started noticing the trend last year. “Everyone wants an iPhone.”

Teens have represented 6 to 8 percent of total arrests in the District for the past five years. What’s changing is their crime of choice.

Last year, 381 juveniles were arrested in robberies or carjackings, compared with 257 arrested in 2007. Police arrested 186 young people accused of riding in stolen cars last year, compared with 506 in 2007.

One of the main reasons for the shift is that anti-theft devices made it increasingly difficult to steal a car about the same time smartphones started becoming more prevalent.

“Stealing cars got too hot,” said a 21-year-old man who as a youth spent time in the former Oak Hill detention center. “You can grab a phone and go.” He spoke on the condition of anonymity, fearing reprisals at his job.

Snatching smartphones has a somewhat similar appeal to stealing a car: The thief can enjoy it for a while, make calls or access Facebook. Then he can sell it on the street for instant cash. On Craigslist, iPhones sell for about $250.

Teens are breaking into houses more than ever, according to police, contributing to a 14 percent jump in home break-ins across the city.

“Burglary is considered a property crime, but that’s a dangerous assumption,” Lanier said. “It’s a very serious crime. I don’t think the kids realize just how dangerous it is.”

Burglaries can quickly become violent encounters if a homeowner is unexpectedly in the house or a neighbor comes by to check on a strange noise.

Juveniles committing crimes have drawn particular attention in recent weeks: On Saturday, a 15-year-old was suspected of shooting a D.C. police officer several times in Northeast Washington. Last month, a 16-year-old was stabbed, allegedly by another teen, at the National Zoo. Several days before, two teens were shot midafternoon at a busy intersection on U Street, allegedly by other teens.

And five D.C. teens have escaped from secure detention facilities in recent months. One of them beat a guard and was on the run for two weeks.

One tangible way to cut down on juvenile crime, Lanier said, is to reduce truancy. If youths are in school, they’re not committing crimes, she said. She estimated that 80 percent of the city’s home break-ins by teens happen during school hours.

“Truancy is a gateway crime,” Lanier said. “It leads to gang activity, and it leads to crime. It is a huge, huge contributor to juvenile crime.”

During the first semester of the 2010-11 school year, about 3,700 students were considered truant. About 13 percent of the students in grades six through 12 were “chronically truant” that semester, meaning they had 15 or more unexcused absences. When police find youths who are not in class during the day, they take them to school.

Police officers based in schools, called school resource officers, are doing home visits for students who are “on the border of getting in trouble,” Lanier said.

This year, police have made nearly 300 home visits for truancy, she said.

The city has formed a truancy task force with eight agencies, including the police department, the courts, schools and youth services. The point is early intervention, said Paul Quander, deputy mayor for public safety and chief of staff for Mayor Vincent C. Gray (D).

“We don’t want to wait until that child is brought before a judge before we intervene,” Quander said. “Chances are, that child has a sibling or cousin in the same household who also needs help. We are trying to fish further downstream when they’re little minnows, before they become big fish in the criminal justice society.”

Lanier said that when police brass have their morning crime briefings, she can count on most of her commanders standing up and saying iPhones, iPods and iPads had been snatched from outdoor tabletops in the previous 24 hours.

But she said she doesn’t blame victims for using electronics in public.

“I do it personally,” Lanier said. “But I’m usually in uniform, so that probably discourages them.”