These are great for the individual case where a single rule exists. That big stack of signs in the beginning of the article is there because there's different

These are great for the individual case where a single rule exists. That big stack of signs in the beginning of the article is there because there's different traffic control being used at different times during the week. Whether good or bad, they've gone the route of drilling their statistical analyses down to parts of week days (and school day or holiday, in some cases) to determine traffic flow and how parked cars effects it. Not saying one is better than the other. Just, that the systems that result come from different initial conditions.