OVERVIEW

This layer is the official state-maintained street transportation dataset available from MassGIS and represents local and major roadways, including designations for Interstate, U.S. and State highways.

Formerly known as the Massachusetts Highway Department Roads, it includes linework from the 1:5,000 Road and Rail Centerlines that was interpreted as part of the Black and White Digital Orthophoto project. The Executive Office of Transportation - Office of Transportation Planning (EOT-OTP), which maintains this layer, added other linework using the Color Orthophoto Imagery as a base. Previous versions of this layer mostly comprised linework from the USGS 1:100,000 Roads Digital Line Graphs (DLGs), with some centerline and ortho-based line features. In addition to the new linework, the attribute table includes all "road inventory" items that previously (pre-Yearend 2004) had been part of a separate table. The inventory data were attached to the linework through a conflation process completed by EOT-OTP. See the Attributes section below for more details.

The layer is up-to-date through December 2007.

This layer is named EOTROADS_ARC. Created from this layer are two subsets that may be useful in smaller-scale mapping:
 - EOTMAJROADS_ARC comprises major roads (CLASS = 1 through 4).
 - EOTMAJROADS_RTE_MAJOR is a multi-part line feature class consisting of all Interstate and U.S. routes and several major State routes.

MassGIS received the year-end 2007 Road Inventory Data from EOT-OTP and further processed the data to facilitate display, particularly in the MassGIS Data Viewer and OLIVER. Processing included:

• adding the CLASS and ADMIN_TYPE items, used for line and route marker (shields) symbolization
  
• adding the ALTRTNUM<1-4> and ALTRT1TYPE items for enhanced route marker labeling
• adding the RT_NUMBER and STREET_NAME items so that existing applications that use these fields would continue to function

To produce the Major Roads layer (EOTMAJROADS_ARC), MassGIS selected arcs where CLASS = 1, 2, 3 and 4 from the full layer, dropped all fields included in the original layer from EOT-OTP, and dissolved on all the fields added by MassGIS to reduce the number of arc segments. (Because of software limitations encountered during processing, the major roads layer was converted to a coverage, and was CLEANed and DISSOLVEd in ArcInfo Workstation before being converted to an ArcSDE layer).

The Major Routes layer (EOTMAJROADS_RTE_MAJOR) was produced by MassGIS from the Major Roads layer by selecting all features where ADMIN_TYPE = 1 (Interstate) or 2 (U.S.), or where the RT_NUMBER or any of the alternate route numbers for state routes (ADMIN_TYPE = 3) is 2, 3, 8, 9, 18, 24, 25, 28 or 128. In ArcToolbox 9.2, these roads were dissolved as multi-part features on the ADMIN_TYPE and RT_NUMBER items. This layer was produced for fast display at small (e.g. statewide) scales rather than for true route-based analysis.

Fields from MassGIS

Each arc in EOTROADS_ARC contains the following fields added by MassGIS:
 

Item Name		Defnition		Description
CLASS		1-I		Designates a road based on functional classification and access; used for plotting. Classes are:  1 - Limited Access Highway  2 - Multi-lane Highway, not limited access  3 - Other numbered route  4 - Major road - arterials and collectors  5 - Minor street or road (with Road Inventory information, not class 1-4)  6 - Minor street or road (with minimal Road Inventory information and no street name) Note: Tracks and Trails (formerly CLASS codes 7 and 8) have been removed from this layer and are now part of the statewide Tracks and Trails datalayer. The CLASS item was first calculated to 0 for all records and then coded in Oracle SQL*Plus based on the following WHERE clauses:  1: (ACCESSCONTROL = 1 AND ROUTENUMBER IS NOT NULL) OR (ACCESSCONTROL = 1 AND ROUTENUMBER IS NULL AND STREETNAME NOT LIKE 'RAMP%')  2: ACCESSCONTROL <> 1 and NUMBEROFTRAVELLANES > 1 and OPPOSITENUMBEROFTRAVELLANES > 0 and ROUTENUMBER IS NOT NULL  3: CLASS = 0 and ROUTENUMBER IS NOT NULL and ROUTENUMBER NOT LIKE 'N%'  4: CLASS = 0 and FUNCTIONALCLASSIFICATION IN (2,3,5)  5: (CLASS = 0 and FUNCTIONALCLASSIFICATION IN (0,6)) OR (CLASS = 0 and STREETNAME <> ' ' and STREETNAME NOT LIKE 'RAMP-RT%' and STREETNAME <> ' ')  6: CLASS = 0
ADMIN_TYPE		1-I		Type of route in the RT_NUMBER field. Based on the ROUTESYSTEM field. Types are:  1 - Interstate  2 - U.S. Highway  3 - State Route  0 - Not a numbered route
STREET_NAME		50-C		Street name. Same as the STREETNAME field.
RT_NUMBER		4-C		Primary route number. Route number of the road type listed in ADMIN_TYPE (where ADMIN_TYPE is 1-3). Based on the ROUTENUMBER field but not including values that begin with "N", which are codes used internally by EOT-OTP and not actual route numbers.
ALTRTNUM1 ALTRTNUM2 ALTRTNUM3 ALTRTNUM4		4-C		Alternate Route numbers. Type is either U.S. or State route for ALTRTNUM1, as indicated in the ALTRT1TYPE item. All other alternate routes are State routes. No road in the state has more than four alternate routes.
ALTRT1TYPE		1-I		Administrative Type for the route number in the ALTRTNUM1 field (U.S. Highway = 2, State Route = 3)

The Major Roads layer EOTMAJROADS_ARC contains only the above fields added by MassGIS. The CLASS item contains values 1, 2, 3 and 4.

The Major Routes layer EOTMAJROADS_RTE_MAJOR contains only the ADMIN_TYPE and RT_NUMBER items.

Fields from EOT-OTP

The other fields in the arc attribute table were included in the data from EOT-OTP. For details see the Road Inventory Data Dictionary (PDF format, 112 kb). The Road Inventory File has a new database structure consisting of better-named fields than those used in the previous file and revised fields to make data more user-friendly.

When downloading the data as a shapefile, please be aware that since the shapefile format only allows for ten characters, the longer Road Inventory File field names have been truncated when converted from an ArcSDE layer to a shapefile. See the conversion chart (PDF format, 9 kb) between the geodatabase field names and the shapefile field names for clarification.

Pre-Yearend 2004 versions of the Road Inventory contained a unique identification number called County Serial Number or CSN. That number was created manually with the addition of new roads or segments. In the new file, a new unique identification field called ROADSEGMENT_ID has replaced the CSN. This ID is generated automatically by EOT-OTP with the creation of new segments or the splitting of existing segments. Splitting will only take place when modifications to the major highway system must be performed, such as with the new Central Artery in Boston. Local road additions will not affect the existing ROADSEGMENT_IDs assigned. To provide a link between the Road Inventory and previous versions, an Access-based table was created by EOT-OTP that links the CSN to the new ROADSEGMENT_IDs. Users relying on the CSN to relate to the road inventory should add the ROADSEGMENT_ID to their data and use the new ID instead of CSN. This should be a one-time conversion, as all newly added roads will not have a CSN link. Download the conversion table (WinZipped MS Access database, 3 MB). For internal use within EOEEA, this table is stored in ArcSDE as EOTROADS_ARC_CSN. This table is only up-to-date for the Yearend 2004 layer and was not updated for any subsequent releases.

Please note that ROADSEGMENT_ID is not unique for every arc segment in this layer. The field is unique in the base dataset used by EOT-OTP for editing; some arcs assigned a ROADSEGMENT_ID may then be split due to attribute changes when joined to one or more event tables in EOT-OTP's linear referencing system, and one ID may remain attached to several arcs.

The The Executive Office of Transportation - Office of Transportation Planning regularly updates this layer. MassGIS receives the official EOT-OTP version and after completing the processing described above makes updated data available once a year.

In November 2001, roads defined as Tracks and Trails were removed from this layer and placed in their own statewide layer, Tracks and Trails.

Also see the Highway Exits and Routemarkers layers.

Since the EOT-OTP roads do not contain address ranges, they may not be used for address matching (geocoding) in GIS software. Currently the only roads data available from MassGIS that may be used for geocoding applications are the TIGER roads from the 2000 U.S. Census.

Last Updated 6/10/2008
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