Neal Lawson at home in Arlington, Va., with his three children, Cooper, 7, Booker, 5, and Sadie, 3. About a year ago, his wife, Jennifer, was struck and killed by a dump truck as she loaded Sadie into a minivan outside an elementary school. (Linda Davidson/The Washington Post)

When Sadie Lawson spots her dad on his computer or phone, the 3-year-old will sometimes hop onto his lap with a simple request: “I want to see Mommy.” Together, she and Neal Lawson scroll through the pictures — Mom at the beach, Mom in her wedding dress, Mom helping her children carve pumpkins — their moods instantly uplifted by the memories.

About a year ago, Jennifer Lawson had just loaded Sadie into her minivan outside of Arlington’s Nottingham Elementary School when a passing dump truck hit her — a grisly crash that left three children without their supermom. Neal Lawson, 42, said he told his kids that night what had happened: “Mommy was in an accident and was killed, and the doctors did everything they could but she didn’t make it.”

He was not sure whether they fully comprehended the loss. He is not sure he did, either.

By the account of her husband and friends, Jennifer Lawson, 39, was a driven public relations professional who left a career she loved so she could be there for all of her kids’ firsts instead of just hearing a babysitter describe them. She went to their sporting events, volunteered at their schools and made sure they had plenty of play dates.

Just before the crash, she had built a display at Nottingham, where her oldest was in kindergarten.

An undated photo of Jennifer Lawson. Family friend Megan Szwez said people still approach her and talk of how they ran a little farther, played a little longer with their children or read an extra bedtime story “because they knew Jenn would.” (Handout/Courtesy Neal Lawson)

“She was so programmed and built to be a mother,” Neal Lawson said in an interview at his Arlington home. “There’s nothing she enjoyed more in life than loving her children, and she was great at it.”

Cooper is 7 now, Booker, 5, and Sadie, 3. Lawson said they don’t often ask about what happened, though they also don’t shy from talking about their mom. Early on, Lawson said, the boys would crawl in bed with him to remember their mother’s life or to pray.

Megan Szwez, 38, a longtime family friend who also lives in Arlington, said Jennifer Lawson’s children “talk about her all the time” — especially about their many trips to the beach. And around the holidays, Szwez said, the kids insisted on making a particular type of cookies.

“They want to make the same ones that Mom made,” Szwez said.

At a memorial service at Little Falls Presbyterian Church on Tuesday, the anniversary of Jennifer Lawson’s death, Booker perched on his father’s lap — his anguished face nestled in his dad’s shoulder — while his brother sat in a chair on Neal Lawson’s right. Sadie sat, until she grew restless, with a nanny, peering over the woman’s shoulder as she clutched a stuffed animal and set of plastic keys.

How the kids are doing is hard to articulate.

“There’s no example to measure against, other than to say that they are remarkably resilient, which I know that they get from their mother,” Lawson said. “They miss her, they know she’s gone, but they’re awfully resilient.”

Neal Lawson and his children (from left) Booker, age 5, Sadie, age 3, and Cooper, age 7. (Linda Davidson/The Washington Post)

Lawson said that he stopped working at his computer-consulting company, iDiscovery Solutions, for about three months after his wife’s death and that even when he came back, he felt at first like an “empty suit.” His parents moved in to help take care of the kids and left about a month ago. Now, Lawson said, he employs two nannies to work in shifts from about 7 a.m. to 7 p.m.

Lawson said the family is “okay” and buoyed by the support of their neighbors and friends. He said that he has a list of “300 babysitters” and that people stop by with full meals for him and the kids.

But this is not the life they envisioned.

In the early days, Neal and Jennifer were an adventurous, idyllic couple. Both were committed to physical fitness — they met at a spin class that he was teaching — and both loved to vacation wherever they could find a beach.

They were married in 2005 and after some years decided — as they had always intended — to expand their family.

Each pregnancy seemed more challenging than the one before it, Lawson said. Cooper was four weeks premature, his brother five weeks and his sister six weeks. Jennifer Lawson battled gestational diabetes, which forced her to keep to a strict diet and workout plan. She had been doing public relations work but gave that up soon after Cooper was born.

She insisted on having Sadie not because she wanted a girl but because “she just felt we weren’t complete yet,” Neal Lawson said.

On the morning of Feb. 24, 2014, Lawson said, he gave his wife a kiss while she was still in bed, told her he loved her and headed out for a day of meetings in Baltimore. When he finally was able to check his phone on a break, he found 13 missed calls and a bevy of texts. One from his assistant was particularly chilling.

“Call me now,” it said.

Lawson eventually made his way to Inova Fairfax Hospital, where his wife was hooked up to a variety of tubes and machines. At some point, he said, he saw Jennifer Lawson move — which he interpreted as a signal she was battling to stay alive.

“I said, ‘You keep it up, you keep fighting, you’re going to get better,’ ” Lawson said.

The doctors, though, soon ushered him out of the room and started CPR. When they next emerged, they told him his wife had died.

“It’s just impossible to be prepared for that moment,” Lawson said, “and I wasn’t.”

Szwez, who was the family’s emergency contact, said she gathered the children, and they played at her house until their father came back home. Lawson broke the news to them that night. Police eventually charged the dump truck driver, Marvin Valladares, now 34, with failure to give full time and attention to driving.

Prosecutors said Valladares was driving just too far to the right, and the step on his truck was just over the line that separates traffic from the area where Jennifer Lawson’s minivan was parked. He was found guilty of the traffic infraction in June and ordered to spend six days in jail.

An attorney for Valladares declined to comment for this article. Lawson said he did not immerse himself deeply in the investigation or court process.

“I’m angry that my wife is gone, angry at life, angry at world circumstances, but I wasn’t looking for retribution,” Lawson said.

Lawson said he has devoted himself instead to honoring his wife’s memory. On the anniversary of her death, Lawson announced formally that he had started the Jennifer Bush-Lawson Foundation to help provide funding for mothers-to-be and mothers with newborns. Michele Werner, the director of development for Virginia Hospital Center, said he had already been working with her group to support those causes and had raised about $45,000.

Szwez, the family friend, said people still approach her and talk of how they ran a little farther, played a little longer with their children or read an extra bedtime story “because they knew Jenn would.”

“It just shows how her personality is living on through everyone,” Szwez said.

Lawson, of course, has also poured himself into a more personal cause: his children. He said he still coaches soccer for his sons and volunteers in their classrooms. In the hospital, shortly after his wife died, he took her hand and promised “to make it my life’s mission to make sure they were always okay,” Lawson said. He knows he has a good head start.

“She created an amazing foundation for them,” he said, “and her love lives on in them.”