Marietta resident Dana Wachsmann drove past the South Loop on Interstate 75 around 10:30 a.m. March 31 on her way to an appointment. A white dog was running along the shoulder. She pulled over and tried to catch the dog.

Acworth resident Roxane Fox noticed Wachsmann on the I-75 roadside with the dog. She thought it was Wachsmann's dog. She stopped to help.

Confused and frightened, the dog started running close to traffic.

Deann Seckinger, also of Marietta, saw the two women and the dog. She didn't hesitate to pull over and help, but the dog darted into the path of a tractor-trailer.

"The tractor-trailer was able to stop and avoid hitting him. ... It was an act of God," Wachsmann told Northeast Cobb Patch. "Someone blew their horn. The dog ran into another lane and was hit."

Would you have stopped to save a stray dog? What do you think of Gravitt's rescue? Tell us in the comments below.

The women watched as a man stopped in traffic, got out, lifted the injured dog and carried him to Wachsmann. He left before the women could learn his name or thank him.

"We'd all give anything to know who that man was and thank him. He's an angel," Wachsmann said.

Marietta police Officer A. Gravitt stopped to assist the women. The dog was in severe shock.

Gravitt escorted the women to Windy Hill Veterinary Hospital, where veterinarian Kathy Rottersman said there was hope.

"The dog's pelvis was detached from his spine, but there was no nerve damage. She told me that he could live with surgery. If it were my dog, I'd want him saved. I guaranteed payment for the bills," Wachsmann said.

The dog had no microchip, no collar tags.

The hospital needed the dog's name: Gravitt, named for the police officer who helped get him there.

Gravitt was treated at Windy Hill and later at Georgia Veterinary Specialists.

His first surgery reattached his pelvis to his spine. The surgery took more than three hours. He later had a plate put in to reinforce the fractured pelvic bone, and his right leg had to be pinned back into the socket.

More was to come: knee reconstruction; parts of his leg pinned together; and laser therapy to help heal his bones.

Seckinger is fostering Gravitt as he recovers. She takes him to rehabilitation appointments and is helping him learn to walk again.

No owner has claimed Gravitt, Wachsmann said.

Gravitt's veterinary bills total $7,500.

Friends and strangers touched by his story have donated $1,400 to help with the medical costs.

"My friend's 10-year-old daughter, Annie Robertson, donated $5 out of her piggy bank, made him a get well-card and an ornament for his collar," Wachsmann said.

You can make a tax-deductible donation to help Gravitt by mailing it to Georgia Veterinary Specialists, 455 Abernathy Rd., Sandy Springs, GA 30328. Make the check payable to "Donation Gravitt: Account #5315."

You also can donate through PayPal.