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Data is what drives many decisions within Land Use and Development. Maps allow interpretation of vast amounts of data visually to see the spatial component to the underlying data, for example, is the proposed school near the center of the population? At the RPC data is used to inform opinions every day. Data can be in tabular format, or it can have a spatial component too. The RPC maintains a GIS for this reason. GIS is a tool that allows data to be used in a spatial way. Each thing you see on the map can be related to a table that has information about that shape. GIS enables the ability to look at what the spatial component of the data means in relation to other things on the map. Simply put, GIS is a tool that allows the user to make maps, data, and join non-spatial data to spatial data to gain more insight.

The vast majority of data that the RPC uses was created and is maintained by other agencies. GRANIT is a primary source of GIS data for the State of NH.

The following are some of the most common data sets utilized by RPC and member communities:

  • Population Projections (OEP and US Census Bureau)
  • Traffic Count Locations (NHDOT)

Population Projections

RPC Staff is working with the State Office of Energy and Planning (OEP), other New Hampshire regional planning commissions, and RLS Demographics to create an updated set of 2040 county and municipal population projections for all of New Hampshire. The projections utilize the cohort-component projection method to develop a picture of the population in the future based on OEP and US Census estimates of current population, assumptions about fertility and mortality rates, as well as recent migration patterns.

In the last few decades New Hampshire has seen slowly declining fertility rates and increasing mortality rates that has led to a slowdown in natural population growth (births – deaths= natural population change), and that meant that much of the population growth has resulted from people migrating into the state. Migration rates (total net migrants divided by the beginning period population) are much more volatile than fertility and mortality rates however, and vary geographically as well, leading to substantial differences in impacts over time and in different parts of the state. Looking back to the 1990s, New Hampshire enjoyed the highest net migration rate (5.3%) during the 1995-2000 period and saw substantial population growth at that time. By the 2005-2010 period the rate had slowed to 0.2% as the impacts of the economic downturn at that time were in full effect, and population growth slowed substantially as well. The most recent five-year period shows an increased rate of migration (0.8% for 2010-2015) for the state however, as in the past, there is substantial variation between counties. Rockingham County has the highest current net migration rate at 2.4% while the more rural southwestern corner of the state and Coos County continue to see declining population and a current negative migration rates.

The RPC utilizes population projections for a wide variety of planning purposes but in general, they are used to estimate future needs for infrastructure and services. Most recently, population projections were utilized in the update of the Regional Master Plan to conduct a scenario planning analysis of the impacts of different magnitudes and distributions of growth on the transportation system of the region and to help identify the need for capacity improvements on the roadway network. That analysis can be read in the Scenario Planning chapter of that document as well as in the recommendations of the Transportation Chapter. The new projections are anticipated to be completed at the municipal level during June, 2016 and will be posted to the RPC website when they are complete. For the most recent set of official projections visit the Office of Energy and Planning webpage on Population Projections in the State Data Center.

  • The New Hampshire Office of Energy and Planning (NHOEP) has released new population projections up to the year 2040 for the state, its counties, and its municipalities. The total New Hampshire state population is projected to be 1,432,730 in 2040, an increase of 116,260 or 8.8 percent from the population at the 2010 census. Data can be found here:

Traffic Counts

NHDOT conducts periodic traffic counts at many locations around the state to enhance transportation planning efforts. The following map represents the locations where traffic count data is collected within the RPC region.

NHDOT Traffic Counts

The New Hampshire Department of Transportation collects all traffic volume counts conducted by the Regional Planning Commissions each year and produces an annual traffic volume report. These counts can be accessed either by municipality or by state highway route number. The detailed count sheets are available for many of these locations as well and provide hourly volume numbers.

Traffic Volumes listed by County and Municipality

Traffic Volumes listed by State Route Number

Traffic Volume Detail Sheets by Municipality

Automatic Traffic Recorder Counts are also available for the approximately 75 locations around the state where permanent counters have been installed. These reports show monthly volumes, including average weekday, average Saturday, and average Sunday volumes, back to 2003. The 200 highest hour reports are available for each of these locations for each year as well.

Automatic Traffic Counter Reports

200 High Hour Reports