In some cases the reason for new towers is not coverage but capacity. The towers out in the rural areas do not have that many voice channels installed. It doesn't take but one roamer from another region listening to their home dispatch talkgroup to take away a voice channel from the local users.
If you look at the main highways, this is the place where the roamers from outside the region will normally be traveling. Planning on the state wide system has in general been done very well. You will find that in some regions, the system looks like it is way over built. But in reality, it has been installed that way to take into account the large numbers of users that either live in these regions or travel through those regions on a daily basis.
Probably the prime region for this high roamer traffic is in St. Tammany Parish. It is a bedroom region for a large number of people that work in other areas. As a result, the traffic is on the high side for the system with these people coming into this area for the night or weekend. It can drive your scanner crazy if you don't lock out all the external talkgroups your not interested in.
If an incident takes place in the normal coverage area of these commuting roamers, you hear that traffic on your local towers if you have a roamer there. Yes it does chew up the limited voice channels available in many of the regions of the state.
