There is the famous new-car smell.

And then there are four new Blue Bird Corporation buses the South Kitsap School District added to its fleet after winter break that extend that scent.

Or lessen it.

Jay Rosapepe, SKSD director of transportation, said district officials elected to eschew traditional diesel engines for propane-powered buses with their latest purchase. He said the change came for a variety of reasons. During the 2013-14 school year, several people who lived near the transportation facility complained about bus traffic and noise. In an effort to mitigate those concerns, SKSD gained approval to park in the city’s commercial zones in May. The district also moved the start time for buses from 4 to 5 a.m.

Rosapape said the new propane buses, which are 5 decibels quitter than contemporary diesel models, will further resolve those noise concerns.

“It’s significant,” he said. “As we switch out some of the older buses our noise profile is going lower.”

In addition to the quieter ride and safety features that come with the new buses, environmentalists will appreciate that they do not emit black exhaust. Also, Rosapepe expects to save money even though propane buses cost $20,000-$25,000 more and average a couple of miles less per gallon than diesels. That is because propane costs less than diesel.

According to the U.S. Energy Information Administration, the average price for a gallon of diesel on Jan. 19 was $2.93, while propane was $2.39. The rates for SKSD — Rosapepe did not have exact figures — are different because the district signed a contract to fuel its propane buses at Ferrellgas.

“We did receive a nice price break from them because they’re trying to attract customers to the service station,” Rosapepe said.

“Our big hang-up was where we were going to fuel the buses. Once we were able to do the contract with Ferrellgas it was in everybody’s best interest.”

The Type C category propane-fueled buses are slightly smaller than their diesel counterparts — Rosapepe said they seat 71 elementary-school students — and service routes west of Highway 16 because Ferrellgas is located in that area.

As for safety, www.blue-bird.com claims that propane fuel tanks are 20 times more structurally puncture-resistant than typical gas and diesel tanks.

Rosapepe, who said SKSD joins Bethel, Tonasket, Omak, Oak Harbor, Meridian, Sedro-Woolley, Bellevue, Highline, Ocean Beach and Seattle as Washington state school districts that use propane buses, added that his drivers have acclimated quickly to their new vehicles.

“It’s good feedback so far,” Rosapepe said. “They like that they’re quieter and everybody loves a new vehicle.”

The most significant drawback, he said, is the off-site service station. But he said the cost to build a propane station would be $75,000-$100,000 and the district might not gain clearance from the fire marshal because its transportation building is located in a residential neighborhood.

A district-owned propane fuel station might only make sense if SKSD plans to standardize its fleet with those buses, though. Rosapepe said he would like to gather driver feedback during the next year before he makes a recommendation on whether the district should purchase more propane-powered buses.

Also, Rosapepe is not sure how large the district’s budget will be to replace buses next year. He said might purchase some “good used buses” to replace others that are 20 years old.

In January 2014, SKSD purchased a pair of 15-year-old larger buses for $2,500 from the Bremerton School District. A few months later, Rosapepe purchased 11 used buses — seven from the Issaquah School District and four from a transportation cooperative that services the Kalama, Woodland, Ridgefield and La Center school districts in the southwest portion of the state. Rosapepe said that purchase enabled SKSD to surplus 13 buses with an average age of 22 years.

Rosapepe thinks the district could move toward a split of propane and diesel buses because the latter still are better for “longer runs and for field trips.” But he could envision a scenario where all SKSD buses run on propane fuel at some point.

“Propane and alternate fuel stations are popping up everywhere,” Rosapape said. “I don’t think there’s anything that would stop us from running a propane fleet entirely at some point in the future.”