I agree the distinction between "complicated" and "complex" is useful; and your example of "building a bridge" vs "managing traffic" is a good one.
But in general I don't think the simple / complicated / complex / chaotic distinction is useful, for a few reasons:
a. it ignores the distinction between stochastic and non-stochastic processes.
b. "chaos" has a specific meaning in non-linear systems which is not correctly captured by "no relationship between cause and effect".
c. a process can be "simple" and still be unpredictable. For example, simple non-linear systems can be chaotic.