Prepare Roads

Summary

Prepare Roads buffers your input roads polyline features to the road width, in preparation for Moderate Consequence Area (MCA) calculation as defined in 84 FR 52180. The tool then buffers the road width polygons by the Potential Impact Radius (PIR), and finally calculates road PIR buffer centerline intersection segments.

Usage

  • Calculation Type – This parameter enables you to specify HCA–MCA calculation method. (The same method should be applied to all tools in a given HCA–MCA analysis workflow.) The Gas HCA Tool supports both method 1 and method 2 HCA–MCA calculations, as defined by 49 CFR §192.903(1) and (2), respectively.

1. Road Inputs

  • Input Road Features – Road data sources and schemas vary widely. The tool assumes that you have already created an appropriate roads feature class or feature layer containing only designated interstates, other freeways, or expressways, as well as any other principal arterial roadways with 4 or more lanes, as defined in the Federal Highway Administration’s Highway Functional Classification Concepts, Criteria and Procedures, Section 3.1. Your road features must contain the following attributes:
      • Road Width Field(s) – Your input road features must contain one or more fields that, when combined, define the paved surface width, including shoulders, of your road features. The field(s) you select are summed to arrive at total road paved surface width.
      • Roads Width Units – This parameter allows you to specify the linear units for your road width attributes. Units can be either ‘Feet’ or ‘Meters.’
      • Road Width Divisible Factor – Your road width attributes likely defines the actual road width. When buffering the road polyline features to create road polygons, a value of half the road width is generally used, since the buffer operation buffers both sides of your road features. This parameter defines the value by which the sum of your road attributes is divided to arrive at a proper buffer radius width. The default value is 2, and need not be modified in most instances.
      • Road Width Tolerance – This parameter allows you to specify an additional road width spatial tolerance to be added to be to the road width buffer distance to account for uncertainty in the spatial position of your road and/or centerline features.

2. Centerline PIR Inputs

  • Input Centerline PIR Buffer Features – This tool requires as input the centerline PIR segment buffer features output by the Create Centerline PIR Buffers tool. Unless otherwise specified, the tool defaults this parameter to the HCA_PIR_SEGMENT_BUFFER feature class in your selected Gas HCA Tool project geodatabase.
      • PIR Field – Identifies the field that stores the PIR value. The default value is the PIR field.

3. Centerline Inputs

  • Input Centerline Features – This tool requires as input the centerline features output by the Copy Centerlines tool. Unless otherwise specified, the tool defaults this parameter to the CENTERLINE feature class in your selected Gas HCA Tool project geodatabase.
      • Centerline Route ID Field – Identifies the field that uniquely identifies your centerline features. The default value is the ROUTE_ID field.
      • Centerline Begin Measure Field – Identifies the field that stores the begin measure values for your centerline features. The default value is the BEGIN_MEASURE field.
      • Centerline End Measure Field – Identifies the field that stores the end measure values for your centerline features. The default value is the END_MEASURE field.

4. Output Features

  • Output Road Features – This output stores a copy of your road features, preserving only those road features within twice the PIR of the centerline features, and only the selected width attributes. Unless otherwise specified, the default destination for the output road features is the SOURCE_ROADS feature class in your selected Gas HCA Tool project geodatabase.
  • Output Road Width Buffer Features – This output stores the polygon features created by buffering the input polyline road features to the road width. Unless otherwise specified, the default destination for the output road width buffer features is the ROAD_WIDTH_BUFFER feature class in your selected Gas HCA Tool project geodatabase.
  • Output Road Width PIR Buffer Features – This output stores the polygon features created by buffering the input road buffer features by the PIR width. Unless otherwise specified, the default destination for the output road width buffer PIR features is the ROAD_WIDTH_PIR_BUFFER feature class in your selected Gas HCA Tool project geodatabase.
  • Output Road Width PIR Segment Features – This output stores the polyline features created by intersecting the road width buffer PIR features with your centerline features. Unless otherwise specified, the default destination for the output road width PIR segment features is the ROAD_PIR_SEGMENTS feature class in your selected Gas HCA Tool project geodatabase.

In a typical HCA–MCA analysis workflow, Prepare Roads is run after Create Structure and Site PIR Buffers, and before one of the final HCA–MCA calculation tools, such as HCA-MCA Calculation (Method 2).

Syntax

PrepareRoadsTool_hcapy (project_database, roads_layer, road_width_fields, road_width_unit, roads_width_divisible, {road_tolerance}, {pir_table}, {pir_field}, {centerline_table}, {centerline_routeid_field}, {centerline_begin_measure_field}, {centerline_end_measure_field}, {roads_width_buffer_layer}, {output_roads_segment_layer}, {output_roads_pir_segment_layer})

Parameter Explanation Data Type
project_database

Dialog Reference

Select a Gas HCA Tool project geodatabase created using the Initialize Database tool. The output from this tool is stored in this workspace, by default.

There is no Python reference for this parameter.

Workspace
roads_layer

Dialog Reference

Specify your input road features.

There is no Python reference for this parameter.

Feature Layer
road_width_fields

Dialog Reference

Select your input road width field(s).

There is no Python reference for this parameter.

Multiple Value
road_width_unit

Dialog Reference

Select the desired road width linear units of measure. The default is ‘Feet.’

There is no Python reference for this parameter.

String
roads_width_divisible

Dialog Reference

Specify the value by which to divide the sum of the road width field values. The default value is 2.

There is no Python reference for this parameter.

Long

road_tolerance

(Optional)

Dialog Reference

Specify an additional road width tolerance value, if desired.

There is no Python reference for this parameter.

Double

pir_table

(Optional)

Dialog Reference

Specify your input centerline PIR buffer features.

There is no Python reference for this parameter.

Feature Layer

pir_field

(Optional)

Dialog Reference

Select the PIR Field.

Refer to the tool usage section in this help topic for details.

There is no Python reference for this parameter.

Field

centerline_table

(Optional)

Dialog Reference

Specify your input centerline features.

There is no Python reference for this parameter.

Feature Layer

centerline_routeid_field

(Optional)

Dialog Reference

Select the route identifier field for your centerline features.

There is no Python reference for this parameter.

Field

centerline_begin_measure_field

(Optional)

Dialog Reference

Select the begin measure field for your centerline features.

There is no Python reference for this parameter.

Field

centerline_end_measure_field

(Optional)

Dialog Reference

Select the begin measure field for your centerline features.

There is no Python reference for this parameter.

Field
output_road_layer

Dialog Reference

Specify the destination for your output copied road features.

There is no Python reference for this parameter.

Feature Layer

roads_width_buffer_layer

(Optional)

Dialog Reference

Specify the destination for your output road width buffer features.

There is no Python reference for this parameter.

Feature Layer

output_roads_pir_buffer_layer

(Optional)

Dialog Reference

Specify the destination for your output road width PIR buffer features.

There is no Python reference for this parameter.

Feature Layer

output_roads_pir_segment_layer

(Optional)

Dialog Reference

Specify the destination for your output road width PIR segment features.

There is no Python reference for this parameter.

Feature Layer

Code sample

Prepare Roads

# Import GasHCA Library
import hcapy
# improt Gas HCA Tools
arcpy.ImportToolbox(“C:\Python27\ArcGIS10.6\Lib\site-packages\hcapy\esri\Toolboxes\Gas HCA Tools.pyt”)
project_database = r”C:\projects\GasHCA_Enhancements\A_DOTCLass_Test5.gdb”
roads_layer = r”C:\projects\GasHCA_Enhancements\Test.gdb\Tx_Roads”
road_width_fields =[“MED_WID”,”RB_WID”]
road_width_unit = “Feet”
roads_width_divisible = 2
# Execute tool
arcpy.PrepareRoads_hcapy(project_database, roads_layer, road_width_fields, road_width_unit, roads_width_divisible)

Environments

Current Workspace, Scratch Workspace, Default Output Z Value, M Resolution, M Tolerance, Output M Domain, Output XY Domain, Output Z Domain, Output Coordinate System, Extent, Geographic Transformations, Output has M values, Output has Z values, XY Resolution, XY Tolerance, Z Resolution, Z Tolerance

Licensing information

This tool requires a valid Gas HCA Tool user license or subscription. Please see Request License and Register License for details on obtaining and registering a Gas HCA Tool software license.

Related topics

Tags

High Consequence Area, HCA, Moderate Consequence Area, MCA, Potential Impact Radius, PIR, centerline, roads.

Credits

Copyright © 2016-2020 by G2 Integrated Solutions, LLC. All Rights Reserved.

Use limitations

There are no access and use limitations for this item.