The Roslyn school district, which has been trying to cut transportation costs in recent years, takes its biggest step yet today when it adds three new full-sized, propane-fueled school buses to its fleet of 60 vehicles.
Roslyn's buses will replace noisy diesel-fueled ones, which administrators and scientists say cost more to maintain and are bad for the environment. A fourth liquid-propane vehicle, a van, will arrive in several weeks.
Roslyn follows the Riverhead district, which added two propane-fueled school buses to its fleet in 2011. It now has 12.
Bird Bus Sales, which sells Blue Bird vehicles, said the districts are the only ones on Long Island it services with propane-fueled buses. Bird Bus Sales said Blue Bird has sold to about two dozen school districts upstate; the buses are being used nationwide.
David Shoob, Roslyn's transportation supervisor, said he calculated propane would cost $2 less per gallon than diesel. The district also is eligible for state rebates for using an alternative fuel, Roslyn officials said.
"We're hoping to save a lot," Shoob said. "There won't be fumes, and you won't even notice the idling."
Districts have had to become creative in recent years in squeezing savings out of transportation programs, said Lorraine Deller, executive director of the Nassau-Suffolk School Boards Association. Roslyn, for example, altered its bus routes recently so that stops would be at street corners and half-blocks, with few exceptions for individual houses.
Since superstorm Sandy, however, some school districts have found themselves traveling longer distances and more routes, picking up and transporting displaced students.
"Transportation budgets are a significant part of the school's budget," Deller said. "More efficient routes are always being worked on."
Some school districts have discussed the possibility of sharing routes. In Southampton, some field trips have become "walking" field trips.
Tim Lipman, co-director of the Transportation Sustainability Research Center at the University of California, Berkeley, said propane fuel produces fewer smog-forming emissions than diesel.
The new buses, said Daniel Sperling, a professor and director of the Institute of Transportation Studies at the University of California, Davis, are a promising step up. The real problem, he said, is "these older buses that have old diesel engines that have a lot of particle emissions that leak."
Roslyn and Riverhead expect the buses -- which cost about $100,000 each -- to provide cost savings and environmental upgrades. But as a tool to help stop climate change, Lipman said, "It's not much of a big improvement."
Electric vehicles, or those powered by hydrogen fuel cells, yield more significant changes.
But they are, Sperling points out, "also the most expensive."
The Roslyn fleet
Total buses: 60
Propane-fueled vehicles: 4
Expected savings: $2 per gallon
The Riverhead fleet
Total buses: 104
Propane-fueled vehicles: 12
Savings: 25 cents per mile
Source: School district officials