3.7 ROADS AND TRAILS - Major Code 170

Transportation data are collected in three separate categories (Roads and Trails; Railroads; and Pipelines, Transmission Lines, and Miscellaneous Transportation Features) for each map source, which means that the attribute codes from the three categories are not intermingled. However, the three categories are distributed by the National Cartographic Data Base office as one unit. Where collection of transportation is authorized from a map source, all of the transportation for that source is collected. If there are no features in a particular category on a source, the header record shows that the file was initialized to hold Roads and Trails, Railroads, or Pipelines, Transmission Lines, and Miscellaneous Transportation Features, but the neatlines of the source, the background area, and the area outside the map are the only information digitized for that category.

3.7.1 General Principles

As described in section 3.0.1, generally, if multiple attributes are needed to describe a feature the ordering is not significant. An exception occurs in coding highway route numbers. If a highway is labeled BYP, ALT, or BR, for example, then the route number parameter code must be preceded by the appropriate descriptive code for bypass, alternate, or business. This is important because when multiple descriptive codes are required to describe a road, each descriptive code must be associated with the proper route number.

3.7.1.1 Node Attribute Codes

There are no general principles that apply to node attribute codes.

3.7.1.2 Area Attribute Codes

There are no general principles that apply to area attribute codes.

3.7.1.3 Line Attribute Codes

USGS maps use symbology to distinguish five classes of roads plus trails. The symbology is easily understood on standard maps. However, on provisional edition maps, some assumptions may have to be made about the class of the road. On provisional edition maps, if the road class is not indicated, the route designation must be used to determine the road class: Interstate and U.S. numbered highways are always class 1; State highways are generally class 2; county highways are class 2; other improved roads for which there is no route descriptor to indicate administrative responsibility are class 3.

The line attribute codes for roads distinguish between the five road classes and trails. In addition, the codes describe whether the road is undivided (symbolized with two casings), the road is divided by a narrow median (symbolized with three casings), or the road is a divided highway with lanes separated by a wide median (symbolized with two separate roads).

The symbol books do not always provide unique symbol numbers. For example, in reference C, a class 1 and class 2 highway have the same symbol number. This should not be a problem because the symbols are easily differentiated.

Every road must receive a code that identifies the road class (170 0201-170 0212; 170 0217-170 0223), unless it is a ramp in an interchange (170 0402) or a nonstandard section of road (170 0405).

Roads are always digitized as a centerline. Some depictions of roads can indicate minor changes in road width or shape. This occurs most often in suburban developments where stub roads, decorative plantings, partial cul-de-sacs, and other "bumps" in the roads have been symbolized and the road casings deviate from parallel lines. This also commonly occurs with road "flares" at road junctions. Small parking areas or pull-off areas have also been symbolized. This level of detail should be ignored when collecting the centerline. Only major changes in road width and shape are collected, using the descriptive code for road width (170 065-) or road in transition (170 0222).

Roads that underpass other features, including other roads, railroads, buildings, and runways, are collected using the code for underpassing (170 0607), if the road symbol has been broken to indicate that it underpasses. Roads that pass through snowsheds are collected continuously, as though the snowshed were not there, and are given all appropriate attribute codes.

3.7.1.4 Single-Point Attribute Codes

There are no single-point attribute codes.

3.7.1.5 General Purpose Attribute Codes

There are no general principles for general purpose attribute codes.

3.7.1.6 Descriptive Attribute Codes

The only descriptive attribute codes that can stand alone are submerged or in ford (170 0606) where it is applied to a node, or covered bridge (170 0624) where it is applied to an isolated covered bridge that is not on a road. In all other cases, descriptive codes must be used with a primary attribute code, either from the list of line attribute codes, or from the list of general-purpose attribute codes.

The descriptive attribute code for road width (170 065-) distinguishes between road symbols whose width varies by 0.005 inches and measurement may be required to determine the appropriate road width code. However, the vast majority of roads are shown with the standard width symbol, and therefore, do not require measurement. For those roads that are shown with a nonstandard width symbol, it should be possible to determine the symbol width easily, if the map was prepared carefully. If it is not possible to determine symbol width easily, because one symbol represents a range of road widths (10 feet), choose the smaller road width.

3.7.1.7 Parameter Attribute Codes

Assigning route numbers to road segments involves interpreting the placement of the route shields on the map. This is not always a straightforward task. Although the route shields were originally placed on the map to provide clear indications of the extent of the numbered route, because of various State requirements for numbering the roads, it can be difficult to determine whether route numbers are continuous or when a road has multiple route numbers, particularly where multiple numbered routes join and split. In general, on any given map, interstate and U.S. numbered highways will be continuous and every effort should be made to identify each segment of the road with the appropriate route number. (Interstate and U.S. numbered highways are not necessarily continuous across the entire country or even an entire State.) State and county route numbers, however, are not necessarily continuous and this varies by State. If a numbered route joins another numbered route and both route numbers are shown next to the segment of road, assign both route numbers to the segment of road. If, however, a numbered route joins another numbered route and only one route number is shown next to the segment of road, assume the segment carries only the one route number and assign only one route number. If the numbered route that was dropped when it joined the other numbered route reappears after splitting from the other numbered route, allow the route to be discontinuous.

The entity responsible for roads varies by state; use the following information in determining whether a route number is a State or county route.

County route numbers have only been shown on maps in Florida, Missouri, and Wisconsin. In Missouri and Wisconsin, if a route number is symbolized with the State route shield (a circle) and it contains an alphabetic designator, it is collected with a county route number (176 ----). In Florida, county route numbers are no longer required and these route numbers are not collected in the DLG, even though they are shown on the map. (County route numbers in Florida have been shown with a rectangular route shield.)

In Texas, farm-to-market roads have been shown with the State route shield (although it becomes an ellipse instead of a circle because the route number is generally 4 digits). These route numbers are collected with (174 ----), State route number.

All other route numbers symbolized with the State route shield are collected using the State route number (174 ----). Note that if the State route number is four digits, the State route shield will be elliptical, rather than circular.

3.7.1.8 List of Roads and Trails Attribute Codes

3.7.2 Node Attribute Codes

This code identifies a bridge wing tick shown by symbols 137, 138, 146 (A); 112.83, 116.6 (B); 511.15, 516.11(C); or 2105.01, 2105.02 (D). Digitize a node where the bridge wing tick intersects the centerline of the road. See code 170 0602 for coding the bridge.

This code identifies a tunnel portal shown by symbols 139(A), 112.83, 116.5(B), 511.17, 516.12(C), or 2105.03(D). Digitize a node where the tunnel portal tick intersects the centerline of the road. See code 170 0601 for coding the tunnel.

This code identifies a gate, other than a tollgate (see code 170 0403), shown by the same tick as symbols 104(A); 511.26(C); or 2103.06(D). Must be labeled "Gate." Digitize the gate as a node where the gate tick intersects the centerline of the road. This code does not apply to 1:100,000-scale maps.

This code identifies a cul-de-sac shown by symbols 116.10(B); 516.7 (C); or 2103.09(D). When a cul-de-sac is shown with a solid symbol, with no interior island, digitize a node and assign this code only. Do not use this code when the cul-de-sac is shown with an interior island. Instead, digitize a centerline along the road and code as appropriate for the road class; generally class 3 (170 0209) on 1:24,000-scale maps, and class 4 (170 0210) on 1:100,000-scale maps).

This feature is no longer collected.

This code identifies a drawbridge shown by the circle portion of the drawbridge symbol: 138(A); 511.15, 516.11 (C); or 2105.02(D). Digitize a node in the center of the circle. See code 170 0618 for coding the road segments on both sides of the circle portion of the drawbridge symbol. This code does not apply to 1:100,000-scale maps.

3.7.3 Area Attribute Codes

This code is described in section 3.0.6.1.

This code is used to identify the area beyond the national boundary to distinguish it from the background area. The perimeter of the void area is collected as an unattributed line, unless it is defined by a road.

3.7.4 Line Attribute Codes

This code identifies a class 1 road shown by symbols 100, 101 (A); 121.1(B); or 511.10(C). It is also used for symbol 2103.01(D) when labeled as an interstate or U.S. numbered highway. Digitize a centerline along the road.

If the road exceeds the standard width for the map scale, add the appropriate road width code (see codes 170 0650 through 170 0659).

This code identifies a class 1 road symbolized with three casings as shown by symbols 109(A) or 511.11(C). It is also used for symbol 2103.02(D) when labeled as an interstate or U.S. highway. Digitize a centerline along the middle casing. If the middle casing is broken (to indicate breaks in the median for turning), collect the centerline as if the breaks did not exist.

If the road exceeds the standard width for the map scale, add the appropriate road width code (see codes 170 0650 through 170 0659). This code does not apply to 1:100,000-scale maps.

This code identifies a class 1, divided highway, symbolized as separate roads as shown by symbols 110(A), 121.1(B), 511.11(C). It is also used for symbol 2103.02(D) when labeled as an interstate or U.S. numbered highway and the lanes are separated. Digitize a centerline in each lane of a divided highway. Crossovers on divided highways are digitized as a centerline and coded using the appropriate road class code.

If the road exceeds the standard width for the map scale, add the appropriate road width code (see codes 170 0650 through 170 0659).

This code identifies a class 1, one-way road as symbolized by a directional arrow. Digitize a centerline along the road. One-way roads generally occur in urban areas in which major through streets may be designated as one-way. This code is not used if the road is part of a divided highway (see code 170 0203). This code does not apply to 1:100,000-scale maps.

This code identifies a class 2 road shown by symbols 102, 103(A); 121.2(B); or 511.10(C). It is also used for symbol 2103.01(D) when labeled as a State or county highway. Digitize a centerline along the road.

If the road exceeds the standard width for the map scale, add the appropriate road width code (see codes 170 0650 through 170 0659).

This code identifies a class 2 road symbolized with three casings as shown by symbols 109(A) or 511.11(C). It is also used for symbol 2103.02(D) when labeled as a State or county highway. Digitize a centerline along the middle casing. If the middle casing is broken (to indicate breaks in the median for turning), collect the centerline as if the breaks did not exist.

If the road exceeds the standard width for the map scale, add the appropriate road width code (see codes 170 0650 through 170 0659). This code does not apply to 1:100,000-scale maps.

This code identifies a class 2, divided highway, symbolized as separate roads as shown by symbols 110(A), 121.2(B), 511.11(C). It is also used for symbol 2103.02(D) when labeled as a State or county highway and the lanes are separated. Digitize a centerline in each lane of a divided highway. Crossovers on divided highways are digitized as a centerline and coded using the appropriate road class code.

If the road exceeds the standard width for the map scale, add the appropriate road width code (see codes 170 0650 through 170 0659).

This code identifies a class 2, one-way road as symbolized by a directional arrow. Digitize a centerline along the road. One-way roads generally occur in urban areas in which major through streets may be designated as one-way. This code is not used if the road is part of a divided highway (see code 170 0208). This code does not apply to 1:100,000-scale maps.

This code identifies a class 3 road shown by symbols 105(A), 116.1(B), or 516.1(C). It is also used for symbol 2103.01(D) when there is no route descriptor to indicate administrative responsibility. Digitize a centerline along the road.

This code identifies a class 4 road shown by symbols 106(A), 116.2(B), 516.4(C), or 2103.11(D). It is also used for street patterns in built-up areas on 1:100,000-scale maps shown by symbol 116.7(B). Digitize a centerline along the road.

This code identifies a trail shown by symbols 107, 133(A), 116.3(B), 516.5(C), or 2103.12 (D) that is NOT labeled to indicate it is designated for four-wheel-drive use. The trail symbol may be labeled in various ways such as "foot trail," "pack trail," or "bicycle trail" although the type of trail is not encoded. For trails labeled "Old Railroad Grade," add code 170 0605.

This code identifies a class 5 road shown by symbols 107(A), 116.3(B), 516.5(C), or 2103.12(D) that is labeled to indicate it is designated for four-wheel-drive use. Generally labeled "Jeep Trail" or "4WD."

This code identifies a footbridge shown by symbols 140(A), 511.23(C), or 2105.04(D). The footbridge is digitized as a line, from wing tick to wing tick, even when the connecting footpaths are not shown. The nodes at ends of the line segment are unattributed. This code does not apply to 1:100,000-scale maps.

This code identifies a road ferry crossing shown by symbols 150, 151 (A); 112.84(B); 511.24(C); or 2105.09(D). The ferry crossing is digitized as a line, from shoreline to shoreline.

This feature is no longer collected.

This code is no longer used.

This code identifies a class 3 road symbolized with three road casings as shown in symbol 109(A) but without the red fill. It is also used for symbol 2103.02(D) when there is no route descriptor to indicate administrative responsibility. Digitize a centerline along the middle casing. If the middle casing is broken (to indicate breaks in the median for turning), collect the centerline as if the breaks did not exist. This code does not apply to 1:100,000-scale maps.

This code identifies a class 3, divided road, symbolized as separate roads as shown by symbols 110(A) (without the red fill) or 516.2(C). It is also used for symbol 2103.02(D) when there is no route descriptor to indicate administrative responsibility. Crossovers on divided highways are digitized as a centerline and coded using the appropriate road class code. This code does not apply to 1:100,000-scale maps.

This code identifies a class 4, one-way road as symbolized by a directional arrow. This code does not apply to 1:100,000-scale maps.

This code is no longer used.

This code identifies a class 3, one-way road as symbolized by a directional arrow. Use this code for symbols 2103.01(D) when there is no route descriptor to indicate administrative responsibility and designated for one-way traffic. This code does not apply to 1:100,000-scale maps.

This code identifies a centerline digitized in a section of any road where a change in the road width occurs, and the transitional section is equal to or greater than 0.5 inches in length. An unattributed node is placed at the beginning and end of the extent of the transitional segment. The road classification is assigned to the transitional segment of the road for connectivity.

When a change in road width occurs, and the transitional section is less than 0.5 inches in length, the narrower width road is carried through the transitional segment, following the centerline, until the wider width is attained. The road in transition code is not used.

This code identifies a road that runs through a service facility, rest area, or viewpoint. The service road must have definite entrance and exit points and must be separate from the roadway it serves. Digitize a centerline along the service road. Do not collect a pull-off area that is shown only as a wide spot in the road.

Common labels include "Service Facility," "Service Area," "Service Plaza," "Rest Area," "Roadside Park," "Viewpoint," "Vantage Point," or "Overlook."

This code is described in section 3.0.6.3.

3.7.5 Single-Point Attribute Codes

There are no single-point feature attribute codes in this category.

3.7.6 General Purpose Attribute Codes

This code identifies a traffic circle, which is a junction of roads (three or more) that forms a circle around which traffic normally moves in one direction (not to be confused with a cul-de-sac or with a road intersection with a center island). Traffic circles are shown by symbols 114(A); 116.10, 121.10 (B); 511.28, 516.6 (C); or 2103.09(D). The feature is digitized as a centerline that follows the circle and is broken by unattributed nodes at the points where the roads join the circle. Road classes and route numbers are also encoded on this centerline as appropriate; the classification assigned is that of the highest class of road entering the traffic circle.

If the traffic circle is symbolized as a solid circle without a center island, do not collect a traffic circle; digitize an unattributed node in the center of the circle and join all of the roads to the node.

A ramp is a road that connects two or more roads that are grade-separated (in other words, the roads cross at different levels, generally by underpassing or overpassing, or both). This code does not apply to connecting roadways between two roads that are at the same grade; such turning roadways are collected using the appropriate road class codes.

This code identifies a ramp in an interchange, shown by symbols 115(A); 121.5(B); 511.13(C); or 2103.10(D). Digitize a centerline along the ramp, beginning where the ramp separates from the centerline of one main road and ending where the ramp joins the centerline of the other main road. A ramp in interchange does not carry a road class. A ramp in interchange generally does not carry a route number except in the few cases where a ramp forms the only connection between segments of a numbered route.

All ramps are collected as centerlines of the individual roads, even if on the map, the individual ramps converge and are symbolized with three casings. This occurs most often on exit and entrance ramps on cloverleaf type interchanges.

This code identifies a tollgate shown by symbols 104(A), 511.26(C), or 2103.06(D). If a tollgate falls on a standard width road, digitize a node where the gate tick intersects the centerline of the road. If a tollgate falls on a nonstandard section of road (170 0405), or a road carrying a width code (170 065-), digitize a line, perpendicular to the centerline, from road casing to road casing. Any buildings associated with the tollgate are not collected in the DLG.

Although in some cases larger tollgate structures have been shown to scale and identified as toll plazas, they are collected in the DLG according to the instructions for tollgate; the exact size and shape is not captured.

This code identifies a feature labeled "Weigh Station" or "Agricultural Inspection Station." Several treatments may be used depending on the size of the feature. If shown by a road or ramp only, digitize it as a line. If shown to scale, collect it as an area; the line around the perimeter of the feature is unattributed. If depicted by a located object symbol or building without ramps or roads shown, digitize as a degenerate line.

This code identifies a line digitized on the casings of a nonstandard section, equal to or greater than one inch in length, of any class road. Unattributed nodes are placed on each end of the nonstandard section, on the centerline of the road. One or more lines that begin at one of these unattributed nodes, run perpendicular to the centerline until they reach the casing, then follow the outer edge of the nonstandard section of road until they reach a point on the casing that is on a line perpendicular to the centerline and passing through the other unattributed node, then follow the perpendicular line and end at the other unattributed node, are digitized and assigned this code. Road classification and route number are not assigned to the lines digitized as nonstandard section of road, but are assigned to the digitized centerline that continues through the unattributed nodes.

The nonstandard section of road code is not used when the nonstandard section is less than 1 inch in length; in such cases the road is carried through the section, following the centerline.

Where a change in road width occurs, the road in transition code (170 0222) rather than the nonstandard section of road code is used.

This code is no longer used. See descriptive code for covered bridge (170 0624).

3.7.7 Descriptive Attribute Codes

This code is no longer used.

This code identifies the portion of a road or trail that is shown as being in a tunnel by symbols 139(A); 121.7, 116.5 (B); 511.16, 516.12 (C); or 2105.03(D). The code is applied only to the portion of the road or trail between the wing ticks (see 170 0002 for coding the wing ticks).

This code identifies the portion of a road or trail that is on a bridge indicated by wing ticks as in symbols 137, 138, 146 (A); 116.6, 121.8 (B); 511.15, 516.11 (C); or 2105.01, 2105.02 (D). This code is used only when wing ticks are present and the code is applied only to the portion of the road between the wing ticks (see 170 0001 for coding the wing ticks). When a road on a bridge passes under another road or railroad, for example, as indicated by a break in the road on the bridge, it is necessary to collect both overpassing, on bridge and underpassing (see code 170 0607).

Do not use this code for drawbridges (see code 170 0618).

This code identifies the portion of a class 1 or class 2 road that is labeled "Under Construction." On 1:24,000-scale maps, road under construction is shown by symbols 112(A) or 511.12(C). Class 3, 4, or 5 roads shown on the map as under construction are not collected in the digital file. On 1:100,000-scale maps only class 1 roads under construction are shown, by symbol 121.3(B). The exact extent of the construction is not indicated on 1:100,000-scale maps; apply the code to all sections of the road, extending from the label in both directions, until an intersection with another road or the edge of an urban tint provides a reasonable limit to the portion of the road considered to be under construction.

This code is no longer used.

This code identifies an old railroad grade shown by symbols 133(A), 116.3(B), 516.5(C), or 2104.12(D). Must be labeled "Old Railroad Grade."

Must be used in conjunction with 170 0211 (trail).

No code from the Railroad subcategory is used on this feature.

This code identifies the portion of a road or trail that fords a stream as shown by symbols 147, 148, 149 (A); 516.13(C); or 2105.08(D). In the case of a ford through a single-line stream, digitize a node at the point where the road or trail intersects the stream. In this case the descriptive code stands alone, because codes for road class and route number are not applied to the node. In the case of a ford through a double-line stream, this code is added to the segment of the road from shoreline to shoreline. This code is not used on 1:100,000-scale maps.

This code identifies the portion of a road or trail whose symbol has been broken to indicate that it passes under, rather than intersects, another feature (for example, road, railroad, building, runway, canal). It is shown by symbols 145(A); 116.4, 121.6 (B); 511.14, 516.10 (C); or 2105.06(D). Digitize a line connecting the dropped portions of the road or trail and apply this code. When a road on a bridge passes under another road or railroad, for example, as indicated by a break in the road on the bridge, it is necessary to collect both underpassing and overpassing, on bridge (see code 170 0602 or 170 0618).

This code is no longer used.

This code identifies a road that is labeled to indicate it is a toll road. Generally labeled "Toll Road." Sometimes only a portion of the road, for example, a bridge or a tunnel, has a toll. In those cases, apply this code only to the portion of the road that is on the bridge or in the tunnel.

This code identifies a road or trail that is restricted, such as a road through a military reservation, a road or trail through a ranch, or a fire road in a forest preserve. Must be labeled "Private" or "Restricted." There may be a gate shown at the point where the restriction begins.

This code is no longer used. Any feature labeled "Proposed" is not collected.

This code identifies a road that is constructed over another road or a road on a two-level bridge. The double-decked structure is shown by the standard road symbol appropriate to its class. Must be labeled "Double-decked." This code is not used on 1:100,000-scale maps.

This descriptive code is no longer used. A road in a service facility, rest area, or roadside park is collected using the primary attribute code 170 0223.

This code identifies a road that is labeled "elevated" to indicate that it is raised above ground level. This code is not used on bridges (see code 170 0602).

This code identifies a road that is identified as a bypass route by the presence of the letters BYP in the highway route marker. This code is used in addition to and precedes the parameter code that contains the route number.

This code identifies a road that is identified as an alternate route by the presence of the letters ALT in the highway route marker. This code is used in addition to and precedes the parameter code that contains the route number.

This code identifies a road that is identified as a business route by the presence of the letters BR in the highway route marker. This code is used in addition to and precedes the parameter code that contains the route number.

This code identifies the portion of a road that is shown as being on a drawbridge indicated by wing ticks and a circle as in symbols 138(A); 511.15, 516.11(C) or 2105.02(D). This code is used only when wing ticks and the circle are present and the code is applied only to the portion between the wing ticks. See 170 0001 for coding the wing ticks. See code 170 0007 for coding the circular portion of the drawbridge symbol. This code does not apply to 1:100,000-scale maps.

This code identifies a road that is described as a spur route by the presence of the word SPUR in the highway route marker. This code is used in addition to and precedes the parameter code that contains the route number.

This code identifies a road that is described as a loop route by the presence of the word LOOP in the highway route marker. This code is used in addition to and precedes the parameter code that contains the route number.

This code identifies a road that is described as a connector route by the presence of the abbreviation CONN in the highway route marker. This code is used in addition to and precedes the parameter code that contains the route number.

This code identifies a road that is described as a truck route by the presence of the abbreviation TR in the highway route marker. This code is used in addition to and precedes the parameter code that contains the route number.

This code is no longer used.

This code identifies a bridge that is labeled "Covered." A covered bridge is always collected as a line. This code is always used in conjunction with the overpassing code (170 0602), except when it is applied to an isolated covered bridge that is not on a road. When applied to an isolated covered bridge that is not on a road, this code stands alone.

Descriptive attribute codes 170 0650 through 170 0659 are used to describe roads that are scribed to scale rather than shown by standard size symbols. This code applies only to 1:24,000-scale maps. At 1:24,000-scale, roads shown with the symbol undivided, equal to or less than 45 feet on the ground, are shown with the standard width road symbol (0.02 inch). If the road is greater than 45 feet on the ground, the symbol width is increased by 0.005 inch for each 10 feet of road width. Roads whose symbol is divided by a centerline equal to or less than 75 feet on the ground are shown with the standard width for a road with a centerline (0.035 inch). If the road is greater than 75 feet on the ground, the symbol width is increased by 0.005 inch for each 10 feet of road width. However, variations in width that are not sustained for at least one-half mile (1.33 inches at 1:24,000-scale) are not collected. The specific widths associated with each code are listed below. The first three codes do not apply to class 1, 2 or 3 roads, symbol divided by centerline (codes 170 0202, 170 0206, or 170 0217).

3.7.8 Parameter Attribute Codes

This code is described in section 3.0.6.4.

For roads, if any part of the symbol, (the casing or the fill, or both) is shown in purple, add this code. If only the route designator (road shield) is shown in purple, do not add this code. When a road divided by a centerline has been added during photorevision, sometimes the centerline has been symbolized, and sometimes it has not. Such roads are collected as shown on the map. If the symbol is divided by a centerline on the map, the appropriate symbol divided by centerline code is applied. If the symbol is not divided by a centerline on the map, the appropriate symbol undivided code is applied, and a width code is added.

This code is no longer used.

This code is used to encode the route number of an interstate highway. Enter the number shown on the highway route marker in the spaces, flush right, one to four digits. If the route number contains alphabetic characters, also use 177 XXYY. If the highway is labeled BYP, ALT, BR, or so on, this parameter code should be preceded by the appropriate descriptive code, such as 170 0615, 170 0616, or 170 0617, respectively. Do not encode the uppercase I that is sometimes associated with an interstate highway, because this parameter code imparts that information.

This code is used to encode the route number of a U.S. numbered highway. Enter the number shown on the highway route marker in the spaces, flush right, one to four digits. If the route number contains alphabetic characters, also use code 177 XXYY. If the highway is labeled BYP, ALT, BR, or so on, this parameter code should be preceded by the appropriate descriptive code, such as 170 0615, 170 0616, or 170 0617, respectively. Do not encode the uppercase "US" that is sometimes associated with a U.S. highway, because this parameter code imparts that information.

This code is used to encode the route number of a State highway. Enter the number shown on the highway route marker in the spaces, flush right, one to four digits. If the route number contains alphabetic characters, also use code 177 XXYY. If the highway is labeled BYP, ALT, BR, or so on, this parameter code should be preceded by the appropriate descriptive code, such as 170 0615, 170 0616, or 170 0617, respectively. Do not encode the uppercase SR that is sometimes associated with a State highway, because this parameter code imparts that information.

This code is used to encode the route number of a reservation, park, or military route number. Enter the number shown on the highway route marker in the spaces, flush right, one to four digits. If the route number contains alphabetic characters, also use code 177 XXYY. If the highway is labeled BYP, ALT, BR, or so on, this parameter code should be preceded by the appropriate descriptive code, such as 170 0615, 170 0616, or 170 0617, respectively. This code is not used on 1:100,000-scale maps.

This code is used to encode a county route number when shown on a Missouri or Wisconsin map. Enter the number shown on the highway route marker in the spaces, flush right, one to four digits. Because the route number contains an alphabetic designator, also use code 177 XXYY. If the highway is labeled BYP, ALT, BR, or so on, this parameter code should be preceded by the appropriate descriptive code, such as 170 0615, 170 0616, or 170 0617, respectively. This code is not used on 1:100,000-scale maps.

This code is used to encode the alphabetic portion of any route number, by substituting numeric values for the alphabetic characters as follows:

If one letter is encoded, it is entered in the YY portion of the code with blank coded in the XX portion. This code is used in conjunction with the appropriate code, 172 ---- through 176 ----, if the route designation is mixed numeric and alphabetic; this code precedes or follows the code for the route number in accordance with its actual position in the route designator. In the case of an entirely alphabetic route designator, also use the appropriate code to specify jurisdiction (173 ---- through 176 ----) with 0000 entered into the minor code.

Do not use this code to represent ALT, BR, BYP, I (interstate), SR (state route), US (United States), SPUR, LOOP, CONN (connector), or TR (truck route), as these qualifiers of the route number are encoded by other codes.

The following examples illustrate the use of this parameter code:

State route B143 is encoded 177 0002, 174 0143

County route 6R is encoded 176 0006, 177 0018

U.S. route A1A is encoded 177 0001, 173 0001, 177 0001

State route KK is encoded 177 1111, 174 0000

U.S. route ALT 1 is encoded 170 0616, 173 0001

This code is no longer used.

This code is no longer used.