Fewer kids were injured during early morning and after school hours once new traffic lights, pedestrian signals and speed bumps were put around New York City schools, according to a new study.

Those fixtures were added through the Safe Routes to School program, which received over $600 million from the U.S. Congress in 2005 to improve kids' ability to walk and bike to schools across the country.

"Pedestrian injuries for children, while the numbers have gotten better over the past decade or so, they're still pretty dismal," said Charles DiMaggio, who worked on the new study at Columbia University in New York.

As a result of Safe Routes to School, the city's Department of Transportation undertook safety improvements at the 124 New York City schools (out of a total of 1,471) with the highest injury rates in the city.

For the new study, DiMaggio and his colleague Guohua Li tracked injury rates around 30 schools that had finished safety projects by early 2009.

Between 2001 and 2010, they saw a 44-percent drop in the number of school-aged pedestrians who were injured in the hours just before or just after the school day - from 8 injuries per 10,000 kids each year to 4.4 per 10,000.

In comparison, there was no drop in injury rates in areas without pedestrian safety projects - they held steady over the decade at 3.1 annual injuries per 10,000 students.

The researchers noted in the journal Pediatrics that if the program was expanded, it could prevent 210 pedestrian injuries per year among New York City students.

The deputy director of the Safe Routes to School National Partnership said the same infrastructure changes can positively affect kids' general health, as well.

"We're reducing injuries to kids and when you reduce injuries, parents get more comfortable with their kids walking and biking," said Margo Pedroso, who wasn't involved in the new research.

Physically active kids are healthier, she told Reuters Health, and "one of the easiest ways to do that is to build it into a kid's daily life. Taking that trip to school by foot or on a bike instead of the back of the car, we really urge parents to do it."

For parents who don't think it's safe enough for their kids to walk to school, she recommended working with other parents and the administration to push for sidewalks, new lighting and other safety improvements for the neighborhood.

New York State got $31 million as part of Safe Routes of School, but the partnership no longer receives direct government funding - instead, it's one option states can choose to invest in out of a range of transportation programs, according to Pedroso.

DiMaggio called its impacts "very compelling."

His study was funded by Centers for Disease Control and Prevention and the National Institutes of Health.

"Engineering interventions like traffic calming work," he told Reuters Health.

"Education and enforcement, they're important, but these kinds of permanent changes to the built environment are critical."