Denali National Park may be treating visitors to a smoother, cleaner ride in hybrid buses that are saving cash and public health. Denali has traditionally carted visitors around in school buses, which are now losing favor because of the high concentration of noxious chemicals they spew.

The new hybrid test buses not only look pretty, but are aptly tailored for Denali’s needs. Hybrids are ideal in Denali, where their quieter engines are don’t scare off the charismatic megafauna people have come to see. Hybrids also work best when their drivers stop often, so the braking action can charge the batteries. In this way, buses are ideal hybrid customers as they make many stops all day.

Buses in Denali drive a combined 1.2 million miles per a year. With that scale, the 70% fuel savings offered by the hybrid technology becomes quite significant. Diesel prices have risen in tandem with all oil products, and parks have struggled to afford fuel costs with their limited budgets. Though the hybrid buses cost twice as much as a normal diesel bus, they pay themselves off over time, and faster as oil prices continue to rise.