The days of traditional school buses — diesel fuel guzzlers featuring scant safety characteristics — are coming to an end.

The bus of the future arrived in Napa Friday; it is gentler on the Earth, boasts higher gas mileage and is equipped with innovative safety features.

The delivery ceremony of California’s first plug-in hybrid electric school bus — a vehicle nearly identical in appearance to that of a traditional bus — drew a crowd of approximately 100 people at Napa High School on Friday afternoon. State and county officials, school district members, sponsors and others attended the event.

The cost of the vehicle, approximately $249,000, is more than twice the price of traditional buses, which usually carry a price tag of $95,000, said Ralph Knight, supervisor of transportation for the school district.

The Bay Area Air Quality Management District provided $100,000 to facilitate funding for the hybrid, and other major contributors include the United States Environmental Protection Agency and PG&E. The NVUSD paid $50,000.

“I think this really was (Knight’s) vision. ... And this is the kind of community that can pull off a collaboration like that,” said Barbara Nemko, Napa County superintendent of schools.

The new vehicle, powered by electricity, biofuel and diesel fuel, gets 12.2 miles to the gallon, double the miles per gallon of a typical bus. It will join the Napa Valley Unified School District’s bus fleet on Aug. 20, the first day of school, said Knight.

There are at least 500,000 traditional school buses in the country, which need more than 1 billion gallons of diesel and gasoline annually, according to information from Advanced Energy, the company which engineered the new bus. A typical school bus releases more than 500 tons of pollutants into the atmosphere over 15 years.

“We will be using half the fuel that we would be using in another vehicle. We’ve really cut tons of pollutants that would have been produced,” Knight said.

Although hybrids are more expensive than traditional buses, they are not only less burdensome to the environment, but end up paying for themselves. Knight said biofuel costs about the same as diesel fuel — $3.19 per gallon — but since the hybrid burns fuel at about half the rate of a regular bus, the school district will spend less keeping the vehicle running.

The hybrid bus emits more than 60 percent less nitrogen oxide and more than 30 percent less carbon dioxide than traditional buses, according to the Advanced Energy. The vehicle is manufactured by the IC Corp., an affiliate of Navistar International Corp., which is based in Warrenville, Ill.

The hybrid bus, equipped with seat belts to comply with state law, also boasts cutting-edge safety features. “The emergency panic button makes a call to local authorities and that will kick in the cellular modem and it will turn into a hands-free device. In the meantime, the bus can be tracked through the Web-based GPS site,” said Steven Schulman, president of Bus Radio, the manufacturer of the unit.

The bus, which seats 55, will travel Napa Valley Unified School District’s route T-5, which includes high schools, middle schools and elementary schools throughout the county, Knight said.