By Katherine Shaver
Washington Post Staff Writer
Wednesday, September 12, 2007; 6:20 PM

Tammi Fischer knew something was wrong when a car sped past her on the left shoulder of southbound Interstate 270 at 9 a.m. today, its hazard lights flashing amid the rush hour traffic crawling past Rockville.

When she came upon the car a couple of minutes later, Fischer said, a very pregnant woman was screaming in the front seat as a panicked-looking man shouted one word in accented English: "Baby!"

Fischer, who was heading to work as a substitute health room technician at Kensington-Parkwood Elementary School, said she knelt by the passenger door, tilted the woman's seat back and saw that the baby's head was crowning. With no training in delivering babies but using her own instincts as a mother, Fischer said, she shouted, "Push!" each time she felt the woman's belly tighten with quick contractions.

After five or six pushes, she said, she held a baby boy in her hands. All the while, she said, none of the other drivers stuck on I-270 south of the Falls Road exit pulled over or offered to help.

After what seemed like 10 minutes of shouting and waving at passing vehicles while holding the newborn, Fischer said, a man in a Navy uniform pulled over and called 911 on his cell phone.

The baby, Vieribeckan Bueso Chavez, arrived at Shady Grove Adventist Hospital by ambulance, weighing in at 7 pounds, 7 ounces. He and his mother, Fany Chavez, of Laytonsville, were doing well this afternoon, said hospital spokeswoman Marisa Lavine. The family declined an interview.

Fischer, a county employee for nine months, said she hopes to pay them a hospital visit.

"It's something I'll never forget," Fischer, 35, of Damascus, said. "I have a connection with this kid forever."