Nowadays amusement rides tend to be more humanistic to meet people's reasonable needs. But there are some basic principles in designing the rides.
At first, it is safety principle. Kids are vulnerable group, so their safety needs to be considered as a priority. The site for children's playing place should be far away from traffic and other public places of chaos and large passenger flow. Besides, the site cannot lose connection with the surroundings to become visional blind angle in case of dangers to the kids. Also, the safety of the rides and the detailed design are important as well.
Second, obey the children orientation principle. The design should aim at serving for the kids, and all the design of activity area and the arrangement of amusement rides should confirm to kids' physical characteristics. For example, since the distinction of the height between kids and adults, some barrier that adults can see through easily can completely block the sight of 3-5 aged kids. And chairs designed for adults are not so convenient for the kids.
The last one is the edutainment principle. Given the diversity of kids' activities, the design should combine participation, variety, infotainment, and interestingness together and create a free, full functional activity area with certain cultural connotation. The environment should wield the role of edutainment and increase kids' knowledge through entertainment.