Yes, I have seen that, but, what I'm not sure about is where the lines of demarcation are with respect to which zones are assigned to "Metro," and which are assigned to the "Rural" radio system, which is how the radio systems are named in Radio Reference, which doesn't really define which radio system, Metro or Rural, is assigned to which Zone.
Now, or course, I have speculated which Zones are assigned where, and have done so based on locations disclosed by the radio traffic when I'm paying close attention to traffic on both radio systems. For example, I've guessed at it with respect to what I think might be the boundary that transitions from Metro to Rural along I44. It seems like the boundary between the Metro and Rural systems is around I44 and Hwy. 141, but I've not seen anything "official" that would disclose whether "Metro" correlates with "ALL" Northern Zones, and "Rural" correlates with "ALL" Zones to the South from that point.
I speculate that Metro means North, and Rural means South. But, where, as far as location, is the line of demarcation that divides the radio systems according to Zones? Or, is MSHP mixing these Zones based more on the anticipated volume of traffic versus geographical location of the Zones? I assume it's a geographical assignment, simply because the cars would need to be in closer proximity to the towers that are in their assigned geographical Zones, and not several Counties away from where they're assigned.
Zone 1= Northern St. Louis County
Zone 2= Southern St. Louis County
Zone 3= North St. Louis City
Zone 4= South St. Louis City
Zone 5= Lincoln / Pike Counties
Zone 7= Warren County
Zone 8= Western St. Charles County
Zone 9= Eastern St. Charles County
Zone 10= Southern Franklin County
Zone 11= Northern Franklin County
Zone 12= Northern Jefferson County
Zone 13= Southern Jefferson County
Zone 14= Washington County
Zone 15= St. Francois County
Zone 16= St. Genevieve / Perry Counties
Rather than clutter my scanner with activity that's outside my area, Franklin County, I'm only monitoring the "Rural" radio system right now, which helps to focus more efficiently on traffic in the Franklin County area without the much greater volume of traffic on the Metro system causing me to miss more localized activity in the greater Franklin County area from other local agencies. But, I often wonder if by omitting the Metro system from my scan list, I might be accidentally omitting traffic assigned to the Metro system that might be relevant to my area by excluding the Metro radio system from my Favorites List by turning it off.
I speculate that the "Metro" system is North of the Franklin County Line West to East, then splitting along the Southern St. Charles County line and the St. Louis City Southern city limits, West to East, which would encompass everything North of that line to include St. Louis City, St. Louis County, Warren County, St. Charles County, and that the "Rural" system is everything else to the South of that line, if they're assigning the two respective radio systems by County lines.
I don't have a good answer, just a guess St Louis City/County, St Charles, Jefferson possibly
If you haven't seen this:
wiki.radioreference.com