Bundled in a jacket on a chilly Wednesday morning, Claire Doll stood for 20 minutes near the back parking lot of Catonsville Elementary School diligently tallying the number of cars that dropped off students.
By the time she left her post to go into school, the fourth-grader had counted 72 vehicles, an increase from last month by 19.
"I really like it because I can watch the cars come by and I can help the environment," said Claire, who often carpools to school. "We have to try to get a lot of people to walk, ride the bus or carpool with someone, instead of driving by themselves."
The school encourages students to take earth-healthy transportation on the second Wednesday of each month as part of its ongoing initiative to receive a Maryland Green School Award.
After each second Wednesday, the school charts its progress and includes the information in its newsletter.
In January, 298 students participated in the Walk, Bike, Ride the Bus to School day, 10 more than in December but much less than the 324 in November, according to the school's newsletter.
The school has an enrollment of 436, according to the Baltimore County Public Schools website.
With Wednesday's dark skies, temperatures in the 30s and threat of snow, Nancy Henderson, an instructional assistant at the school, and Rebekah Kaufman, a librarian, expected the number of young commuters to shrink.
"Weather plays very heavily into our numbers unfortunately," Henderson said. "(The number of cars) was actually going down on a pretty regular basis."
But the school's green initiative is about more than a single day.
Henderson explained that for a school to be classified as green by the Maryland Association for Environmental and Outdoor Education, it must adopt four practices.
Catonsville Elementary has chosen responsible transportation, waste reduction, energy reduction and habitat restoration, said Henderson, an instructional assistant.
Signs of the initiative, which is scheduled to end June 2013, are visible all around the school.
Posters in hallways illustrate ways people can become greener by doing things such as emailing fliers or painting a house in cold climates a dark color.
Paper towel dispensers in many bathrooms have signs urging only two pulls on the lever.
The cafeteria has separate containers for recycling and trash.
In reducing waste, the school even managed to raise about $200, Kaufman said, by sending the used pouches from the students' Capri Sun drinks back to the company where they are turned into tote bags, lunch boxes and folders and sold.
Around many light switches, including the one leading into the main office, covers with designs by last year's third-grade class remind people to turn out the lights when leaving a room.
Last school year, the school spent $67,000 on electricity, a $9,000 decrease from the previous year, Henderson said.
In the spring, the school's students plant native species of vegetation around the school, she added.