For kids with autism, a service dog can be just the friend they need, helping to calm them when they're overwhelmed, keeping them safe, and giving parents a little bit of peace of mind.

But CTV News has learned that the organizations that train these service animals are so overwhelmed, wait times for service animals at some locations span years, while others have closed their lists altogether.

Alison Toth would love to get a service dog for her five-year-old son, Carson. Like many children with autism, fear just isn't part of Carson's vocabulary. He has a tendency to bolt from his parents and run without looking or climb up to places he shouldn't go.

Not long ago, while walking with both parents by his side, Carson ran in front of a moving car. Though he wasn't badly hurt, his parents say the incident left them terrified.

"We just lead very, very stressful lives. We are hypervigilant at all times, and we can never rest for a moment," says Toth.

The family has long wanted to get Carson a dog specially trained for children with autism. The dog would be tethered to their son with a strap, and would be trained to sit when Carson wants to run and climb.

But when Toth requested such an animal, she was frustrated to learn it would take two years or more to get one.

"If families reach a point that they need a dog to keep their child safe, they need it now," she says.

There are a handful of accredited agencies that train dogs across Canada. One of them, Dogs with Wings in Edmonton, says they can't keep up with demand.

"We probably get three or four phone calls every day from people wanting a dog, and we have to turn them away. It's a terrible thing," says the group's executive director, Doreen Slessor.

She says some people have been on the wait list for two to three years. After deciding it was not fair to put any more people on the list, they closed it six months ago.

Autism Dog Services near Brantford, Ont., has 48 families on their active waiting list and more on a pending wait list, says Vicky Spadoni.

"It gets very emotional when people call. It's parents begging us, 'Please help us. Our son ran out the door, we caught him.' That's the reality and it's so tough," she says.

The solution, say advocates, is more dogs, more accredited trainers, and government funding programs similar to those that help pay for wheelchairs and other assistive devices.

Training an autism service dog isn't cheap. It costs Autism Dog Services $30,000 per dog to train, feed, and place a dog.

But with most organizations, there is no cost for families who receive the dogs. Instead, families are encouraged to fundraise to support the program and help pay for training future service dogs.

It's not just autism service dogs that involve wait lists. There are waits for other kinds of service dogs too, but the problem is most severe with autism dogs because the use of the dogs is so new and so popular.

For now, Alison Toth knows it will be a long wait to get a dog for Carson, and so she and her family continue to live on the edge. She hopes the wait won't be long.

"These dogs to us, they could be potentially lifesaving for Carson. Literally save his life," Toth says.

With a report from CTV medical specialist Avis Favaro and producer Elizabeth St. Philip