The Tanbark Principle

Scenario 1
A newly constructed block of flats is built, and the city plans for the large number of people living there by building a bus stop directly outside, a car park, and wheelchair access to the flats. Because of the steep gradient from the street to the car park, the wheelchair ramp is built parallel to the street, doubling back on itself to create a long entry point for foot traffic. Residents at the flats become annoyed with having to traverse the ramp, and begin to step through the newly constructed garden beds and jumping into the car park below. The garden beds become trampled, and residents risk injury. The design has failed to meet the goals of the majority of the residents who use the bus.

Scenario 2
A Landscape architect is designing a new playground which will include an adventure playground with various features, a sand pit, drinking fountains, and paved pathways. They construct all of the equipment, but they decide to delay the construction of the pathways. Instead, they spread tanbark evenly around the equipment, including between the equipment and the amenities. The new playground is opened, and receives heavy use over the first 2 weeks. The landscape architects return, and map the areas where the tanbark is thinner. These pathways through the tanbark have been left by regular use of children as they move around the new playground. The landscape architect uses the map to specify where the paved pathways, which are added to the playground to complete the design.

The Tanbark Principle
Instead of trying to design something that you think will allow people to achieve their goal, observe their behaviour to see if they are already finding a good path. If possible, observe many people to map the most common pathways to these goals.