Nobody wants to see this sign again, but because the National Park Service is more than $12 billion behind on maintenance, they are floating a new entrance fee structure which will place the onus of making up that figure on motorcoach groups. This means higher costs for tours, decreased visitation at the parks overall, and more cars.
One of the stated reasons for these changes is to decrease traffic emissions, but in fact motorcoaches are the most environmentally friendly way to travel. One motorcoach takes up to 50 cars off the road, thus relieving stress and congestion at all park facilities.
