Visitors desperate to find a parking spot made their own on ecologically sensitive ground, tearing up native plants with the crush of their vehicles' tires. The rumbling engines of those cars, trucks, campers and motor coaches drowned out the music of the Virgin River waters, the melodies of the hundreds of species of birds who live there and vanquished the whistle and moans of wind in the trees. And the doors. The endless slamming of car doors.

"Someone who has made the effort to make the climb to the top of a cliff doesn't want to hear the sounds of the people below them, getting out of their cars, slamming a door here, slamming a door there because they forgot to get the camera out. They didn't come here to hear that," said Tom Haraden, the park's assistant chief of interpretation and visitor services.

The idea of a seasonal shuttle service was born, and in 2000, it began operations, prohibiting access by private vehicle along the Zion Canyon Scenic Drive — and the park's most heavily traveled destinations — during peak visitation months from April to October.

Resisted early on, the free shuttle is now described universally as an exceptional success story, with each propane-powered bus taking the equivalent of 28 vehicles off the road and logging 12.1 million shuttle passenger miles each year.

The service accommodates tourists by extending through the length of Zion's gateway community of Springdale, home to 550 residents.

With shuttles running every six to eight minutes and leaving the park as late as 11 p.m., tourists can linger at Zion without the fear of long lines and make convenient stops in town for dinner, shopping and back to their own hotel.

The impact to the park is every bit as profound, because not only are carbon-dioxide emissions reduced, but vehicles are not scrambling for a spot to park and tearing up the terrain.

Perhaps most important to the visitor — and to the caretakers of the park — is that it is quieter, more of a place of solitude and reflection and wonder and awe. It is, people say, more of what it is meant to be: a state of being, Zion, that sanctuary and refuge.

email: amyjoi@desnews.com