They are subordinate to the PRI in the case of municipalities that comprise a wider urban unit. These plans incorporate different documents and studies, including a review of the socio-economic situation and potential for (industrial) development, as well as feasibility studies for physical expansion, particularly with respect to service delivery. They also articulate the municipality’s urban centres in terms of population and growth potential; roadway hierarchies, including access and service roads; parking requirements; zoning plans; principal urban activities; assess the infrastructure capacity of roads, large structures and areas designated as at high risk for natural hazards or requiring protection; identify buildings classified as national monuments and traditional zones (zoms tipicas); identify historical buildings or zones.