The National Park Service (NPS) has spent years designing and redesigning transportation plans for Grand Canyon National Park. The current state of these plans calls for a light rail system to be used to shuttle visitors into and out of the park. The stated goal of the transit system is "to provide more convenient access to the park than is now experienced." The premise is that the quality of the visitors' experience is currently being degraded not only by increasing congestion, but by the mere presence of the internal combustion engine.
[T]heir visit is accompanied by the cacophony of automobile engines and horns and the constant growl and screech and smoke of bus motors and brakes. A parking lot, even on the rim of the Grand Canyon, is still a parking lot, with all the fumes and conflicts and fender-benders.
The presumption that Park Service plan is the best of all possible alternatives is just that-a presumption. The plan is founded on weak premises, ignores a host of relevant concerns and yet, if instituted, will likely commit the park to employing this system for many years to come. This paper sets out a rather exhaustive critique of the plan.
In approaching this topic it is important to have an open mind. We should be especially careful about accepting unproven assertions. Although raised in a different context, we would be well served by following Carl Sagan's advice to "[m]istrust arguments from authorities." Going even further than this, it is critically important to actually understand what assertions are being made.
National Park Service "South Rim Transit," www.nps.gov/grca/transit/southrim.htm.
 The Demon-Haunted World: Science As a Candle in the Dark (Random House; New York, 1996) page 28.