Leonard B. Robinson’s three sons sat in the synagogue’s front row Wednesday, hundreds of people dressed in black packed into the seats behind them. And as the men stood and walked to the stage, the matching yellow word stitched on each of their yarmulkes came into view: “BATMAN.”

Grins cascaded over the mourners’ faces.

It was that sort of funeral at Har Sinai Congregation outside Baltimore — more jokes than scripture, more laughs than sobs. Robinson was known to the world as the Route 29 Batman, a wealthy altruist who drove a Batmobile and dressed as the Caped Crusader to delight sick children in hospitals. But his family knew him as LBR, a character even more captivating than the superhero he portrayed.

Justin Robinson, 23, and his 21-year-old twin brothers, Jake and Brandon, gave their eulogies together, taking turns telling stories about their father. Among those listening were strangers wearing Batman gear and children whose lives he’d brightened, some of them on crutches.

Robinson, 51, was killed Sunday night on a Western Maryland highway. He had pulled over in his sputtering Batmobile, and another car struck it as he checked the engine.

Ryan Darby, who battled leukemia from age 6 to 10, says he cried when he heard about the sudden death of Lenny Robinson, who was known as the Route 29 Batman. (WUSA9)

The deluge of sorrowful messages from around the world has overwhelmed his grieving sons, siblings, nieces and parents. Brandon called it a “testament to all the work that he has done and the impact that he had on everyone around him.”

LBR was fueled by people. He made up nonsensical songs about those he loved, called them singing at one minute past midnight on their birthdays and gave everyone he knew a nickname — his pallbearers included “Tinman,” “Big Mike” and “Material.”

“A superhuman mensch,” one friend called him.

He adored kids, of course, but also cigars and cars — especially cars.

“If you lived on Red Maple Court,” Justin remembered, “or really anywhere within a three-mile radius, and you heard a loud, obnoxious speaker blasting disco music accompanied by a cloud of cigar smoke, you knew it was, in fact, LBR washing his car outside.”

Even in freezing winter temperatures that turned the driveway into a sheet of black ice, he’d stay out, chewing on his cigar as he applied one more coat of Turtle Wax.

Mourners leave after funeral services for Lenny Robinson, better known as the Route 29 Batman, who had for years dressed as the Caped Crusader and driven his custom-made car to deliver moments of happiness and distraction to hundreds of sick children at area hospitals. (Jonathan Newton/The Washington Post)

Long before he was pulled over by Montgomery County police in the 2012 traffic stop that made him an Internet sensation, LBR and Brandon showed up at a Baltimore Ravens National Football League game one year dressed as Batman and Robin for Halloween.

Security at the gate stopped Robinson and told him to take off the mask. “Sorry, I can’t do that,” Brandon recounted him saying. “I’m Batman.”

LBR made what his son described as a “fake phone call” to Ravens owner Steve Bisciotti. “Some way or another,” he marveled, “we ended up with Ray Lewis’s family in a suite on the 50-yard line, watching the game as Batman and Robin.”

After Robinson’s death, Lewis posted a photo of the two men together on Facebook, writing above it: “To know a man with his heart, his love for people, his love for life, his love for his family and especially his children is to know a true superhero.”

Lewis was part of a public outpouring of grief for Robinson. Batman’s official Facebook page, which has nearly 13 million likes, expressed its condolences on Monday, as did musician John Mayer. Comic book fans called for the upcoming “Batman v. Superman: Dawn of Justice” movie to honor Robinson in the credits.

A small horde of media showed up at Wednesday’s funeral, including one from RT, formerly known as Russia Today.

“He was well known,” the journalist said in a heavy Russian accent, explaining her presence. “As we say, viral on the social. So that’s why.”

His younger brother, Scott — mimicking Robinson’s energetic voice and fondness for attention — imagined what his brother would have said had he witnessed the reaction: “Can you believe I got over five million hits on that Washington Post article? What do you think of that, Scottieeeeee?”

Robinson became famous three years ago after he was pulled over on Route 29 in a black Lamborghini and full superhero garb.

Video of his Silver Spring encounter with police, who had stopped him because of a problem with his plates — emblazoned with the Batman symbol — went crazy on the Web. But his identity remained unknown until The Post revealed it.

On Wednesday, the good-humored officer who stopped him that day sat near the back of the synagogue, along with other members of Montgomery law enforcement.

Det. Paul Borja, a 32-year veteran who is retiring in a month, had worked all night serving a search warrant but refused to miss the funeral, riding more than an hour with other officers to attend.

Borja had heard from amused friends for months after the video exploded.

He reveled in every detail of the traffic stop — telling dispatch to send Robin, taking a photo of Batman next to the car, learning about the Caped Crusader’s purpose.

“We may be cops, but at this moment,” he said, “we’re kids.”

On Monday, his e-mail account was overwhelmed with messages about the crash.

“He can’t be dead,” Borja thought, and pushed away from his desk, unable to concentrate on his work.

Robinson made his money in the cleaning business, starting a company while in high school that eventually employed more than 300 people.

Even as a teen, an old friend told the mourners Wednesday, he had expensive taste: Polo cologne, Cole Haan shoes, Gucci wallets. He eventually used his wealth to become Batman, devoting hundreds of thousands of dollars to being the character. He had a ’60s-style custom Batmobile built, wore a costume that seemed more real than those in the movies and purchased boxes of trinkets to hand out to children at area hospitals, always autographed “Batman.”

Reilly Brown, 4, is one of those children. The boy suffers from a disorder that causes one of his femurs to grow faster than the other. Propped on his father’s hip outside the synagogue, Reilly wore Batman sunglasses Robinson had given him. And what did his superhero friend do that made him happiest?

“Tickle me,” he said, grinning.

Also in attendance was Elizabeth Gardner, 10, who suffers from TAR syndrome, a rare genetic disorder that has left her arms severely shortened.

Batman once gave a speech at her school, telling her classmates that bullying is wrong and describing Elizabeth as his friend. After her family’s home burned down, he showed up at their hotel room with a load of paraphernalia.

“I was feeling sad when I lost my house,” she said Wednesday. “He just cheered me up.”

Robinson’s brother initially thought that he wore the costume just for the attention — “LBR had a pretty big ego” — until one day when Scott and one of his daughters, playing Batgirl, went to the hospital, too. Their job was to give Batman books to kids after they met the Dark Knight.

He would pick up each child, look into their eyes and say: “Do Batman a favor and get better.”

After talking to one, Robinson told his brother to give the boy a book.

Then Scott noticed — the child had no arms.

And yet, he was still beaming.

When the service ended, dozens of cars followed the black and gray hearse to the burial site, at one point passing a sign that read “Gotham City Thanks You Batman!!!”

At the grave, family members, friends and the children he had made smile dropped dirt onto the casket, as is Jewish custom.

A lone man in a Green Arrow superhero costume stood toward the back of the crowd. No one knew who he was.

As those gathered walked away, the man in green stepped toward the plot and quietly spread his dirt.

The casket was then covered in a hard plastic container with the Dark Knight’s insignia.

And the man inside it — Lenny Robinson, LBR, Batman — was at rest.