HIGHWAY DESIGN MANUAL - Design Criteria Revision 100 (Limited Revision) November 04, 2022 - NY.gov
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HIGHWAY DESIGN MANUAL
Chapter 2
Design Criteria
Revision 100
(Limited Revision)
November 04, 2022
Issued by Engineering Bulletin 22-057
Effective with Design Approval on or after January 1, 2023
DESIGN CRITERIA 2-2
Section Changes
§2.2.7 Culvert Projects Changed subsection name from “Culvert Replacement” to “Culvert Projec ts”.
Added ref erence to Bridge Manual and HDM Chapter 8 f or additional
inf ormation. Added separate sections for culvert rehabilitation and New and
Replacement Culverts
§2.6.2.1 Language under “Determining Bicycle Demand” was reworded for clarity.
§2.7.5.9 Tunnel guidance expanded to include design table and typical section
EB 22-057 D.A. 01/01/2023
DESIGN CRITERIA 2-3
TABLE OF CONTENTS
2.1 INTRODUCTION .......................................................................................................................... 5
2.2 PROJECT TYPES......................................................................................................................... 7
2.2.1 Pavement Preventive and Corrective Maint enance .................................................................... 7
2.2.2 3R - Resurfacing, Restoration and Rehabilitation....................................................................... 7
2.2.3 Reconstruction and New Construction ..................................................................................... 7
2.2.4 Minor Intersection Reconstruction ........................................................................................... 8
2.2.5 Major Intersection Reconstruction ........................................................................................... 8
2.2.6 Bridge Projects ...................................................................................................................... 8
2.2.7 Culvert Replacement .............................................................................................................. 9
2.2.8 Additional Information ............................................................................................................. 9
2.3 DESIGN CRITERIA SOURCES .................................................................................................... 11
2.3.1 A Policy on Geometric Design of Highways and Streets ............................................................. 11
2.3.2 A Policy on Design Standards, Interstate System ...................................................................... 11
2.3.3 NYSDOT Bridge Manual ....................................................................................................... 11
2.3.4 NYSDOT Guidelines for the Adirondack Park ........................................................................... 11
2.3.5 Guidelines for Pedestrian Facilities in the Public Right-of-Way (PROWAG) ................................... 12
2.3.6 Urban Street Design Guide.................................................................................................... 12
2.3.7 National Cooperative Highway Research Program (NCHRP) ...................................................... 12
2.4 FUNCTIONAL CLASSIFICATION OF HIGHWAYS AND CONTEXT CLASSES................................... 13
2.4.1 Functional Classification of Highways ...................................................................................... 13
2.4.2 Context Classes................................................................................................................... 15
2.5 PROJECT DATA ........................................................................................................................ 23
2.5.1 Traffic................................................................................................................................. 23
2.5.2 Terrain ............................................................................................................................... 24
2.5.3 Special Routes .................................................................................................................... 24
2.6 CRITICAL DESIGN ELEMENTS ................................................................................................... 27
2.6.1 Design Speed...................................................................................................................... 27
2.6.2 Lane Width.......................................................................................................................... 28
2.6.3 Shoulder Width .................................................................................................................... 31
2.6.4 Horizontal Curve Radius........................................................................................................ 31
2.6.5 Superelevation..................................................................................................................... 32
2.6.6 Stopping Sight Distance (Horizontal and Vertical)...................................................................... 33
2.6.7 Maximum Grade .................................................................................................................. 33
2.6.8 Cross Slope ........................................................................................................................ 33
2.6.9 Vertical Clearance................................................................................................................ 34
2.6.10 Design Loading Structural Capacity ........................................................................................ 34
2.6.11 Americans with Disabilities Act (ADA) Compliance .................................................................... 34
2.7 STANDARDS ............................................................................................................................. 35
2.7.1 Interstates and Other Freeways.............................................................................................. 35
2.7.2 Arterials .............................................................................................................................. 39
2.7.3 Collector Roads and Streets .................................................................................................. 52
2.7.4 Local Roads and Streets ....................................................................................................... 64
2.7.5 Other Roadways .................................................................................................................. 76
2.8 REQUIREMENTS FOR JUSTIFICATION OF NONSTANDARD FEATURES ....................................... 92
2.8.1 Definition and Procedures ..................................................................................................... 92
2.8.2 Technical Discrepancies........................................................................................................ 92
2.8.3 Documentation .................................................................................................................... 92
2.9 REFERENCES ........................................................................................................................... 99
EB 22-057 D.A. 01/01/2023
DESIGN CRITERIA 2-4
LIST OF EXHIBITS
Exhibit 2-1 Functional Classification & Context Class of Highways - Various Sources ............................... 22
Exhibit 2-1a Shoulder Width Considerations for Bicycles ........................................................................ 30
Exhibit 2-1b Superelevation Rate (Applies to NHS and non-NHS)............................................................ 32
Exhibit 2-2 Design Criteria for Interstates and Other Freeways .............................................................. 38
Exhibit 2-3 Design Criteria for Non-NHS Rural Arterials ........................................................................ 41
Exhibit 2-3a Design Criteria for NHS Rural Arterials............................................................................... 44
Exhibit 2-4 Design Criteria for Non-NHS Rural Town, Suburban, Urban, and Urban Core Arterials .............. 47
Exhibit 2-4a Design Criteria for NHS Rural Town, Suburban, Urban, and Urban Core Arterials..................... 51
Exhibit 2-5 Design Criteria for Non-NHS Rural Collectors ..................................................................... 54
Exhibit 2-5a Design Criteria for NHS Rural Collectors ............................................................................ 57
Exhibit 2-6 Design Criteria for Non-NHS Rural Town, Suburban, Urban, and Urban Core Collectors ........... 60
Exhibit 2-6a Design Criteria for NHS Rural Town, Suburban, Urban, and Urban Core Collectors .................. 63
Exhibit 2-7 Design Criteria for Non-NHS Local Rural Roads .................................................................. 66
Exhibit 2-7a Design Criteria for NHS Local Rural Roads......................................................................... 69
Exhibit 2-8 Design Criteria for Non-NHS Local Rural Town, Suburban, Urban, and Urban Core Streets ....... 72
Exhibit 2-8a Design Criteria for NHS Local Rural Town, Suburban, Urban, and Urban Core Streets .............. 75
Exhibit 2-9 Traveled Way Widths for Ramps and Turning Roadways ...................................................... 80
Exhibit 2-10 Design Criteria for Turning Roadways Not Connecting to the NHS ......................................... 81
Exhibit 2-10a Design Criteria for Turning Roadways Connecting to the NHS............................................... 81
Exhibit 2-11 Minimum Radii and Superelevation for Low-Speed Non-NHS Urban Highways and Streets ....... 85
Exhibit 2-11a Minimum Radii and Superelevation for Low-Speed NHS Urban Highways and Streets .............. 86
Exhibit 2-12 Minimum Radii for Design Superelevation Rates, Design Speeds, and emax = 4% (Non-NHS)..... 87
Exhibit 2-12a Minimum Radii for Design Superelevation Rates, Design Speeds, and emax = 4% (NHS)............ 87
Exhibit 2-13 Minimum Radii for Design Superelevation Rates, Design Speeds, and emax = 6% (Non-NHS)..... 88
Exhibit 2-13a Minimum Radii for Design Superelevation Rates, Design Speeds, and emax = 6% (NHS)............ 89
Exhibit 2-14 Minimum Radii for Design Superelevation Rates, Design Speeds, and emax = 8% (Non-NHS)..... 90
Exhibit 2-14a Minimum Radii for Design Superelevation Rates, Design Speeds, and emax = 8% (NHS)............ 91
Exhibit 2-15 Nonstandard Feature Justification Form ............................................................................. 94
Exhibit 2-15a Nonstandard Feature Justification Form for Pedestrian Facilities............................................ 95
Exhibit 2-16 Design Criteria Table....................................................................................................... 97
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DESIGN CRITERIA 2-5
2.1 INTRODUCTION
NYSDOT has established the following eleven (11) design elements as critical criteria for the
design of highways and bridges based on the controlling criteria established by FHWA:
▪ Design Speed ▪ Maximum Grade
▪ Lane Width ▪ Cross Slope
▪ Shoulder Width ▪ Vertical Clearance
▪ Horizontal Curve Radius ▪ Design Loading Structural Capacity
▪ Superelevation ▪ Americans with Disabilities (ADA)
▪ Stopping Sight Distance (Horizontal and Compliance
Vertical)
Design criteria are influenced by:
▪ The highway functional classification
▪ Traffic volumes (from all surface, highway and transit modes)
▪ Operating speed
▪ Terrain (level, rolling, mountainous)
▪ Development density and land use
▪ Project type (e.g., new construction, reconstruction, 3R, 2R - simple 3R projects)
Design criteria are presented to provide guidance to individuals preparing the plans, profiles and
cross sections. The design criteria for the project alternatives are normally determine d during
the project scoping stage. In making these determinations, the scoping participants sh ould be
aware that the criteria are generally the least acceptable values and, if routinely used, may not
result in the optimum design from a safety, operational, or cost-effectiveness perspective.
Design criteria values should be established taking into consideration the Department’s Context
Sensitive Design philosophy that strives for outcomes that meet transportation service and
safety needs, as well as environmental, scenic, aesthetic, cultural, natural resource, and
community needs. AASHTO’s A Guide for Achieving Flexibility in Highway Design, 2004,
contains guidance on selecting proposed values that take into account the context of the
project.
It is the Department’s policy to at least meet the design criteria values for the individual project
under consideration. However, the selected values used for a project should be inf luenced by
the design criteria and numerous other factors, including:
• Crash history
• Crash potential
• Future plans for the corridor
• Social, economic and environmental impacts
• Purpose and need for the project (e.g., traffic calming, capacity improvement)
• Context of the highway
• Construction cost
• Stakeholder and public involvement (including the road users and communities that the
highway serves)
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INTRODUCTION
DESIGN CRITERIA 2-6
In situations where values do not meet the design criteria values for certain design elements, a
formal justification must be prepared in accordance with Department policy for use of the
nonstandard feature, as specified in Section 2.8 of this chapter. The use of design exceptions
to achieve an optimum design is discussed in AASHTO’s A Guide for Achieving Flexibility in
Highway Design, 2004.
There are other design elements with established values that must be considered in addition to
the critical design elements when scoping and designing a project. These elements can af f ect
some of the critical design elements and have a considerable impact on the cost, scope, and
quality of a project. Examples include design storm, length of speed change (acceler ation and
deceleration) lanes, design vehicle, clear zone, median width, control of access, and level of
service. Since these other elements are not listed as critical design elements, they are not
addressed in this chapter but are discussed in others (e.g., Chapter 5 Basic Design, Chapter 18
Pedestrian Facility Design, and Chapter 17 Bicycle Facility Design).
The inclusion of specified design criteria in this chapter does not preclude the use of
engineering judgment to consider alternative engineering values and does not necessarily mean
that existing roadways, which were designed and constructed using different criteria, are either
substandard or unsafe. Many existing facilities are adequate to safely and efficiently
accommodate current traffic demands and need not be reconstructed solely to meet current
design criteria
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INTRODUCTION
DESIGN CRITERIA 2-7
2.2 PROJECT TYPES
In order to provide consistent methods for developing projects and reporting program data,
projects are categorized into types which are determined by their predominant purpose. When
the project consists of two or more different kinds of work, judgment must be used to identify the
predominant reason for the project in order to select the appropriate type.
When projects have more than a single type of work, it may not be appropriate to use a single
set of design criteria. There may be several sets of design criteria that apply to different
portions of the project or to different alternatives. Separate criteria are to be provided for
adjoining highways when they are being reconstructed to tie into the new mainline.
2.2.1 Pavement Preventive and Corrective Maintenance
Preventive maintenance is defined as those planned activities undertaken in advance of a
critical need or of accumulated deterioration so as to avoid such occurrence and reduce or
arrest the rate of future deterioration. Corrective maintenance is defined as those activities to
correct existing deficiencies. Both of these activities may correct minor defects as a secondary
benefit.
These work types include element specific work such as resurfacing a highway’s pavement and
shoulders (e.g., 1R/2R resurfacing). Work generally also includes measures to address
identified superelevation, pavement marking, signing, delineation, crack and joint sealing,
drainage improvements and necessary safety improvements on approximately the same
alignment. Refer to Highway Design Manual Chapter 7 for further guidance on 1R and 2R
projects.
2.2.2 3R - Resurfacing, Restoration and Rehabilitation
This type of project includes work to preserve and extend the service life of an existing highway,
including any safety improvements justified by existing or potential accident problems. Low cost
operational improvements are also encouraged. Work is generally limited to pavement
rehabilitation along existing alignment, and can include correction of minor subgrade problems,
widening of less than a lane width, minor adjustment of vertical and/or horizontal alignment,
provision of turning lanes at intersections, arterial driveway consolidation, lengthening
acceleration/deceleration lanes and construction of bus turnouts, and pedestrian and bicycle
accommodations. These projects may also utilize Intelligent Transportation System (ITS)
measures, such as signal retiming and detection, ramp metering, overhead sign structures, and
incident detection and management. Work may also include drainage improvement, slope
work, and/or replacement of signs and signals, guide rails and other roadside appurtenances.
Refer to Highway Design Manual Chapter 7 for further guidance on 3R projects.
2.2.3 Reconstruction and New Construction
This type of project includes work to replace an existing highway, including rebuilding to include
geometric improvement, or construction on new alignment. Projects generally involve extensive
rebuilding of subgrade, drainage systems, and utility work. These projects may also utilize IT S
measures. These projects provide a full depth replacement of hot mix asphalt or Portland
EB 22-057 D.A. 01/01/2023 §2.2
PROJECT TYPES
DESIGN CRITERIA 2-8
cement concrete. Highway reconstruction and new construction projects may also include
bridge work, including bridge rehabilitation and bridge replacement. Refer to this chapter and
Highway Design Manual Chapter 5 for further guidance on reconstruction and new construction
projects.
2.2.4 Minor Intersection Reconstruction
This type of project typically provides operational improvements, including geometric c hanges
such as new or lengthened turn lanes, restriping, improved radii, and minor channelization.
Other examples of improvements include installation of traffic control devices and signs,
installation of sidewalks, curbs and bus turnouts, incidental improvements such as lighting and
drainage improvements, and pedestrian and bicycle accommodations. Minor intersection
projects do not involve edge to edge full-depth pavement reconstruction. Refer to Highway
Design Manual Chapter 5 and Highway Design Manual Chapter 7 for further guidance on minor
intersection reconstruction projects.
2.2.5 Major Intersection Reconstruction
This type of project typically includes operational changes, major capacity enhancements, and
relocation/realignment work and usually involves full-depth pavement reconstruction. Major
intersection reconstruction also includes new or revised access points for freeway interchanges,
as defined in Project Development Manual Appendix 8. Major intersection reconstruction may
include but is not limited to, major at-grade signalized intersections, single and multi-lane
roundabouts, diverging diamond interchanges and restricted crossing U-Turn intersections.
These projects may also utilize ITS measures. Refer to this chapter and Highway Design
Manual Chapter 5 for further guidance on major intersection reconstruction projects.
2.2.6 Bridge Projects
Bridge projects are projects where the primary objective is to construct a new bridge or to
replace, rehabilitate, or repair the deck of an existing bridge. Bridge projects would also include
projects where an existing bridge is to be removed. Some incidental highway work may be
included on the approaches to the bridges, as a necessary transition between the bridge and
the unaffected existing highway. Bridge project types are further broken down as shown below.
For additional information, refer to the NYSDOT Bridge Manual.
2.2.6.1 Element Specific Cyclical Bridge Work
Element Specific Cyclical Bridge Work is planned activity done in advance of a critical need
or accumulated deterioration so as to reduce or arrest the current or future rate of
deterioration.
2.2.6.2 Element Specific Bridge Work
Element Specific Bridge Work includes work outside the scope of that in Section 2.2.6.1 and
may include such actions as deck repair, bearing replacement, bridge railing upgrades and
bridge curb or sidewalk replacement.
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PROJECT TYPESDESIGN CRITERIA 2-9
2.2.6.3 Bridge Rehabilitation
Bridge rehabilitation work includes major items such as bridge widening, deck
replacement and superstructure replacement.
2.2.6.4 New and Replacement Bridges
These projects include replacement of an existing bridge, construction of a new bridge or
removal of an existing bridge.
2.2.7 Culvert Projects
2.2.7.1 Culvert Rehabilitation Projects
Culvert rehabilitation projects include activities to repair or extend the service life of an
existing culvert. Culvert rehabilitation projects usually have no or minimal pavement work but
may include limited pavement work that is within the scope of a 1R project. Refer to HDM 8
for technical guidance on culverts and HDM 7.3 for pavement work.
2.2.7.2 New and Replacement Culvert Projects
These projects include replacement of an existing culvert, construction of a new culvert
or removal of an existing culvert. Pavement work on these projects is generally limited to
that within the scope of a 2R/3R project but may require full reconstruction standards if the
reconstruction length exceeds 0.6 mile. Refer to HDM Chapter 8 for technical guidance on
culverts and HDM 2 or HDM 7 for pavement work.
2.2.8 Additional Information
2.2.8.1 Safety Projects
While nearly all Department projects incorporate one or more elements to improve saf et y,
these projects are primarily programmed to address safety needs or include significant
safety elements.
2.2.8.2 Pedestrian and Bicycle Facilities
It is Department policy to address bicycle and pedestrian travel in the programming,
planning, scoping, and design, as well as the construction and maintenance of the State’s
transportation system. Facilities for pedestrian travel may include sidewalks, pedestrian
crossings (including grade separations) and shared-use paths. Facilities for bicycle travel
may include bike lanes, wide curb lanes (shared lanes) and shared-use paths. Note that
shoulders are not pedestrian facilities, although per the NYS Vehicle and Traffic Law
Section 1156, pedestrians are permitted to utilize shoulders where sidewalks are not
provided. In cases where it has been identified that a pedestrian facility is needed and the
shoulder is the only option to accommodate that need, then the designer shall ensure that
the shoulder is designed as described in HDM Chapter 18 (Pedestrian Facility Design).
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PROJECT TYPESDESIGN CRITERIA 2-10
Pedestrian and bicycle facilities may be the primary purpose of a project but are more of ten
included as elements of highway or bridge projects and are not listed as separate work
types in Exhibit 5-1a of HDM Chapter 5. In any case, the needs and objectives for
pedestrian and bicycle traffic should be identified and addressed as part of the overall
project development process, beginning with scoping and continuing throughout design and
construction. Refer to HDM Chapter 17 (Bicycle Facility Design) and HDM Chapter 18
(Pedestrian Facility Design) for further guidance on these facilities.
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PROJECT TYPESDESIGN CRITERIA 2-11
2.3 DESIGN CRITERIA SOURCES
This section provides a brief description of the major sources used to establish geometric
design criteria for new construction and reconstruction projects with over 400 AADT and major
bridge projects on highways with over 400 AADT.
2.3.1 A Policy on Geometric Design of Highways and Streets
This policy was developed by AASHTO's Standing Committee on Highways. Guidance included
in the policy is based on established practices and is supplemented by recent research. The
policy is intended to form a comprehensive reference manual for assistance in administration,
planning, and educational efforts pertaining to design formulation. A recommended range of
design values for critical dimensions of various types of highway facilities is provided.
2.3.2 A Policy on Design Standards, Interstate System
This policy provides standards for design features specific to interstate highways. The
standards outlined in this publication must be followed for projects on the interstate system in
addition to the AASHTO geometric requirements in A Policy on Geometric Design of Hig hways
and Streets.
2.3.3 NYSDOT Bridge Manual
The Bridge Manual was developed by the NYSDOT Office of Structures. Section 2 of the
manual serves as a standard for designers in determining minimum requirements for bridge
widths, clearances, and live loadings for all bridge replacement and bridge rehabilitation
projects. It is also intended to clarify the above geometric design requirements for all types of
bridge work except maintenance.
2.3.4 NYSDOT Guidelines for the Adirondack Park
Although the Guidelines for the Adirondack Park do not establish design criteria, it is referenced
here because it provides important guidelines for consideration when designing projects within
the Adirondack Park. Geometric guidelines for projects within the Adirondack Park are
contained in Chapter IV of this publication.
These guidelines were developed by the Adirondack Park Task Force which is comprised of
representatives of the Adirondack Park Agency, the Department of Environmental Conservation,
and Regions 1, 2, and 7 of the Department of Transportation. They serve as an interagency
guide for the design, construction, and maintenance of highways, bridges and maintenance
facilities within the Adirondack Park. The purpose of this document is to ensure the preservation
and enhancement of the unique character of the Adirondack Park, which may require extra
effort by the designer to ensure that the project fits harmoniously into the natural surroundings.
These guidelines apply to all projects in the Adirondack Park.
When the use of these guidelines results in a value less desirable than that listed as design
criteria, a justification must still be prepared in accordance with Department policy for the use of
the nonstandard feature. Part of this justification should be a reference to these guidelines.
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DESIGN CRITERIA SOURCESDESIGN CRITERIA 2-12
2.3.5 Guidelines for Pedestrian Facilities in the Public Right-of-Way (PROWAG)
PROWAG, also known as the “Public Rights-of-Way Accessibility Guidelines”, is the basis of
the Department’s standards for accessible pedestrian facilities within highway rights of way.
Accessible pedestrian facilities are required by the Americans with Disabilities Act.
Pedestrian facilities that are not within rights of way or in rest areas are subject to the
standards found in the 2010 ADA Standards for Accessible Design. Transit facilities (defined
by ADA as Transportation Facilities) are subject to the 2006 ADA Standards for
Transportation Facilities. These documents are referenced because the legal requirement to
design and construct all pedestrian facilities in accordance with their provisions may have a
direct, unavoidable influence on other critical design elements of a project.
The accessible design standards defined in Chapter 18 of this manual are based on these
documents and must be strictly adhered to unless a formal justification is provided (refer to
Section 2.8 and Exhibit 2-15a). Departures from these standards should be discussed as
nonstandard features.
2.3.6 Urban Street Design Guide
The National Association of City Transportation Officials (NACTO) Urban Street Design Guide
provides guidance for the design of city streets that embrace Complete Streets principles by
accommodating a wide range of travel modes and users.
2.3.7 National Cooperative Highway Research Program (NCHRP)
Numerous problems facing highway engineers and administrators are studied through the
National Cooperative Highway Research Program, which is conducted by the Transportation
Research Board (TRB). Upon completion of the research, the problems and recommended
solutions are presented in an NCHRP report. Information contained in these reports is
considered to be the most current, nationally-recognized data on the topic presented. The
information contained in these reports is usually adopted in subsequent issuances of the design
manuals that host the subject topic.
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DESIGN CRITERIA SOURCESDESIGN CRITERIA 2-13
2.4 FUNCTIONAL CLASSIFICATION OF HIGHWAYS AND CONTEXT CLASSES
Appropriate design criteria are determined by considering both functional classification (the
character of the highway itself) and its context class (the character of the surrounding area in
which the highway operates).
2.4.1 Functional Classification of Highways
Highways are classified by the character of service they provide. Freeways move high traffic
volumes at high speeds with limited local access. Local roads and streets are intended to avoid
high-speed and volume for increased local access. Arterials and collectors provide intermediate
service. The functional classification of a roadway is a major factor in determining the
appropriate design criteria.
The Department’s Functional Classification Maps and Highway Inventory should be referenced
to determine the existing functional classification of the project roadway(s). This information is
maintained by the Highway Data Services Bureau. Functional Class information is available
online through the Functional Class Viewer, found on the Function Classification webpage at
https://www.dot.ny.gov/gisapps/functional-class-maps.
The functional classification terminology does not precisely match that used for design criteria.
Judgment should be used to determine the appropriate design criteria category. For example,
the Functional Classification Maps / Highway Inventory have categories that identify some
routes as “Rural Major Collector” and “Rural Minor Collector”, yet these roadways should
normally be designed utilizing the design criteria for Rural Collectors in Section 2.7.3 of this
chapter. If the designer believes any of the project roadway classifications should be changed
as a result of current or proposed conditions, they should consult the Regional Planning &
Program Management Group to determine if the classification should be revised.
Exhibit 2-1 serves as guide for selecting the appropriate design criteria category for a project
based upon the functional classification as recorded on the Functional Classification Maps and
Highway Inventory.
2.4.1.1 Interstates and Other Freeways
A. Interstates
Interstate highways are freeways on the interstate highway system. Generally, they are
interregional high-speed, high-volume, divided facilities with complete control of access
and are functionally classified as principal arterials.
B. Other Freeways
Other freeways are local, intraregional and interregional high-speed, divided, high-
volume facilities with complete control of access. Most other freeways have been
classified as principal arterials.
Expressways are divided highways for through traffic with full or partial control of access
and generally with grade separations at major crossroads. Section 2.7.1, Interstates and
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FUNCTIONAL CLASSIFICATION OF HIGHWAYS AND CONTEXT CLASSESDESIGN CRITERIA 2-14
Other Freeways, applies to expressways and to multilane divided parkways, including
parkways with occasional at-grade intersections.
2.4.1.2 Arterials
A. Rural Arterials
A major part of the rural highway system consists of rural arterials, which range from
two-lane roadways to multilane, divided, controlled-access facilities. Generally, they are
high-speed roadways for travel between major points.
B. Rural Town, Suburban, Urban, and Urban Core Arterials
Arterials in moderately and densely populated areas generally carry larger traffic
volumes. They vary from multilane, divided, controlled-access facilities to two-lane
streets. They serve major areas of activity, carrying a high proportion of an area's traff ic
on a small proportion of the area's lane mileage.
2.4.1.3 Collector Roads and Streets
Collectors serve a dual function. They collect and distribute traffic while providing access to
abutting properties.
A. Rural Collectors
Rural collectors are two-lane roadways connecting roadways of higher classification,
larger towns, and smaller communities. They link local traffic generators with rural areas.
B. Rural Town, Suburban, Urban, and Urban Core Collectors
Rural Town, Suburban, Urban, and Urban Core collector streets link neighbor hoods or
areas of homogeneous land use with arterial streets. They serve the dual function of
land access and traffic circulation.
2.4.1.4 Local Roads and Streets
A. Local Rural Roads
Local rural roads are primarily town and county roads. Their primary purpose is access
to the abutting property. They constitute a high proportion of the highway mileage, but
service a low proportion of the traffic volume.
B. Rural Town, Suburban, Urban, and Urban Core Streets
Local Rural Town, Suburban, Urban and Urban Core streets are primarily village and city
streets. Their primary purpose is access to abutting property.
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FUNCTIONAL CLASSIFICATION OF HIGHWAYS AND CONTEXT CLASSESDESIGN CRITERIA 2-15
2.4.1.5 Other Roadways
The roadways defined in this section are not considered a functional classification. They
have a different function than the highways discussed in the classifications above, and are
defined here so the appropriate design criteria can be determined.
A. Parkways
These are usually divided highways for noncommercial traffic with full control of access,
grade separations, interchanges, and occasional at-grade intersections. Parkways are
designated by law.
B. Ramps
Ramps are turning roadways that connect two or more legs of an interchange. They
may be multilane.
C. Speed-Change Lanes
A speed-change lane is an auxiliary lane, primarily for the acceleration or deceleration of
vehicles entering or leaving through traffic.
D. Turning Roadways
Turning roadways are separate connecting roadways at intersections.
E. Collector - Distributor Roads
Collector - distributor roads are auxiliary roadways within or between interchanges. T he
purpose of these roadways is to remove weaving traffic from the mainline and to
minimize entrances and exits.
F. Frontage Roads
Frontage or service roads are auxiliary roadways along controlled access facilities. They
provide access to adjacent property.
G. Climbing Lanes
Climbing lanes are auxiliary lanes provided for slow-moving vehicles ascending steep
grades. They may be used along all types of roadways.
H. Intersections
Intersections are covered in Chapter 5 of this manual.
2.4.2 Context Classes
The context of a highway is based on development density, land uses, and building setbacks.
Project developers and designers have the responsibility to determine this classification. The
design criteria classification selected should be made on the basis of the anticipated character
of an area during the design life, rather than political or urban area boundaries. For instance, if
an area within an urban boundary indicated on the Functional Classification Maps is rural in
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FUNCTIONAL CLASSIFICATION OF HIGHWAYS AND CONTEXT CLASSESDESIGN CRITERIA 2-16
character and is anticipated to remain rural in character for most of the design life of the project,
it should be designed utilizing rural criteria.
A project along a single corridor may include more than one context class as it passes through
areas with varying character. The portion of the project in each context class should be
designed with the criteria most appropriate to that class, with appropriate transitions, as needed.
The minimum road segment length for establishing a context class is generally 0.6 miles.
While the context class is, at a minimum, determined to be either “urban” or “rural”, there are
characteristics that often require a more detailed context classification, as described in Section
2.4.2.1. Most of the “typical characteristics” identified for a context should be present to select
that classification.
Where this manual defines criteria for “rural” or “urban” areas, the accompanying discussion
addresses all contexts within the relevant area type. Where the guidance of the policy refers to
a specific context class (e.g.,“urban core”), the guidance applies only to the specific context
class or classes identified.
2.4.2.1 Context Classifications
A. Rural
The rural context has the lowest development density, or no development. Speed
expectations for drivers are higher, with infrequent driveways or intersecting roads, and
few slowing or turning vehicles.
Typical characteristics are:
• Few houses or structures
• Widely dispersed residential, commercial, or industrial land uses
• Large building setbacks
• Undeveloped land, farms, large outdoor recreation areas, or low densities of other
types of development
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Example of Rural Context
Image © 2019 Google
B. Rural Town
The rural town context applies to developed communities within rural areas, and is often
applicable to small town, small village or hamlet. Rural highways change character where
they enter a rural town, and driver speed expectations are lower, with a higher likelihood of
encountering slowed or turning vehicles, pedestrians, and bicyclists.
Typical characteristics are:
• Low development densities with mixed land uses
• Mostly on-street parking
• Average building setbacks < 50 ft.
• Average driveway densities greater than 25 driveways/mile on each side of the road
• May include residential neighborhoods, schools, industrial facilities, and commercial
main street business districts
• Some pedestrian and bicyclist activity, often with sidewalks and marked crosswalks in
some locations
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Example of Rural Town Context
Image © 2019 Google
C. Suburban
The suburban context is often applicable to the outlying portions of urban areas. Drivers
have higher speed expectations than the urban contexts, but lower speed expectations
than the rural contexts.
Typical characteristics are:
• Low- to medium-density development
• Mixed land uses (with single-family residences, some multi-family residential
structures, and/or nonresidential development including mixed town centers,
commercial corridors, big box commercial stores, light industrial development
• Building setbacks are varied
• Driveway densities greater than 20 driveways/mile on each side of the road
• Mostly off-street parking
• Pedestrians and bicyclist activity; may or may not have sidewalks and marked
crosswalks
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Example of Suburban Context
Image © 2019 Google
D. Urban
Driver speed expectations in urban areas are generally lower, with a higher likelihood of
encountering stopped or turning vehicles, pedestrians and bicyclists.
Typical characteristics are:
• High-density development
• On-street parking
• Varied building setbacks
• Multi-story and low- to medium-rise structures for residential, commercial, and
educational uses
• Structures that accommodate mixed uses: commercial, residential, and parking.
• Light industrial, and sometimes heavy industrial, land use
• Prominent destinations with specialized structures, e.g., large theaters, sports
facilities or conference centers.
• High levels of pedestrian and bicyclist activity, with nearly continuous sidewalks and
marked crosswalks
• Higher density of transit stops and routes
• Driveway densities greater than 25 driveways/mile on each side of the road
• Minor commercial driveway densities of 10 driveways/mi. or greater
• Major commercial driveways
• High density of cross streets
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Example of Urban Context
Image © 2019 Google
E. Urban Core
Urban core areas are predominantly in the central business districts and adjoining p ortions
of major metropolitan areas. They have the highest development density and low driver
speed expectations.
Typical characteristics are:
• Mixed land uses with high-rise structures
• Most residences are apartments or condominiums
• Small building setbacks
• On-street parking is usually limited and time-restricted; parking is often located in
multi-level structures attached to or integrated with other structures
• Prominent destinations with specialized structures, e.g., large theaters, sports
facilities or conference centers.
• High volumes of automobiles, including commercial delivery vehicles and buses
• High density of transit stops and transit corridors, including bus and rail transit, often
with major transit terminals
• High levels of pedestrian and bicyclist activity, with continuous sidewalks and
frequent marked crosswalks
• Driveway densities greater than 25 driveways/mile on each side of the road
• Minor commercial driveway densities of 10 driveways/mi. or greater
• High density of cross streets
• Major commercial driveways
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Example of Urban Core Context
Image © 2019 Google
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FUNCTIONAL CLASSIFICATION OF HIGHWAYS AND CONTEXT CLASSESDESIGN CRITERIA 2-22
Exhibit 2-1 Functional Classification & Context Class of Highways - Various Sources 1,4
Classif ication is based upon the service Classif ication determined by the designer based upon
the highway is intended to provide and is conditions anticipated during the design life of the
dependent upon census data and urban project. 2
boundaries
NYSDOT Highway Inventory &
Functional Classification Maps Design Context Class
Criteria Section
Classification Per HDM §2.4.2
Description Code
Urban Principal Arterial - Rural Town,
11
Interstate Suburban, Urban,
Interstate 2.7.1.1
Rural Principal Arterial- Urban Core and
01 Rural
Interstate
Urban Principal Arterial - Rural Town,
12
Other Freeway/Expressway Other Suburban, Urban,
2.7.1.2
Rural Principal Arterial – Freeways Urban Core and
02 Rural
Other Freeway/Expressway
Urban Principal Arterial - Other 14 Rural Town, Non-NHS 2.7.2.3
Suburban, Urban,
Urban Minor Arterial 16 and Urban Core NHS 2.7.2.4
Arterial
Rural Principal Arterial – Other 04 Non-NHS 2.7.2.1
Rural
Rural Minor Arterial 06 NHS 2.7.2.2
Urban Collector/ Major Rural Town,
17 Non-NHS 2.7.3.3
Collector Suburban, Urban,
Urban Minor Collector 18 and Urban Core NHS 2.7.3.4
Collector
Rural Major Collector 07 Non-NHS 2.7.3.1
Rural
Rural Minor Collector 3 08 NHS 2.7.3.2
Rural Local 3 Rural Town, Non-NHS 2.7.4.3
09 Suburban, Urban,
and Urban Core NHS 2.7.4.4
Local
Urban Local 3 Non-NHS 2.7.4.1
19 Rural
NHS 2.7.4.2
Notes:
1. This table presents the general relationship between the Functional Classifications and the Design Criteria.
There may be situations where the association presented will not coincide as shown.
2. Classifications are based on AASHTO’s A Policy on Geometric Design of Highways and Streets, 2018.
3. Classification that is typically not federal-aid eligible.
4. Highway Data Services Bureau maintains the official, most current, record of Highway Functional
Classifications and National Highway System (NHS) designations.
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2.5 PROJECT DATA
The following items are factors in determining the values of some of the critical design elements.
2.5.1 Traffic
2.5.1.1 Traffic Volume
Traffic volume directly affects the geometric features selected for design of highway and
bridge projects. The general unit of measure for traffic on a highway is the two-way,
average daily traffic (ADT), defined as the total volume during a given time period (in whole
days), greater than one day and less than one year, divided by the number of days in that
time period. The ADT volume utilizing a time period of one year is referred to as the two-
way, annual average daily traffic (AADT). An hourly traffic volume is also used for design
purposes. The unit of measure for this traffic is the two-way, design-hour volume (DHV)
which is usually represented by the 30th highest hourly volume of the year chosen for
design. This volume is adjusted to provide a one-way, directional design-hour volume
(DDHV). Refer to Chapter 5, Section 5.2 of this manual for additional information on traf fic
data.
2.5.1.2 Trucks and Other Heavy Vehicles
For consistency with the definition in AASHTO’s A Policy on Geometric Design of Highways
and Streets, the term “trucks” used in this chapter refers to all heavy vehicles. The
Transportation Research Board’s Highway Capacity Manual defines heavy vehicles as
vehicles having more than four tires touching the pavement, and include trucks, buses, and
recreational vehicles. Trucks impose a greater effect on a highway or bridge than
passenger cars do. Truck volumes are generally addressed as follows:
• A very low percentage of trucks is considered to be 2% or less.
• A high percentage of trucks is considered to be 10% or more. For the interstates
and other freeways, a DDHV of 250 vph of trucks is used to indicate a high
percentage of trucks.
2.5.1.3 Traffic Design Year
Highway and bridge design should be based on traffic volumes that are expecte d to occur
within the expected service life of the project. The year chosen for design must also be no
further ahead than that for which traffic can be estimated with reasonable accuracy. Ref er
to Chapter 5, Section 5.2.2.3 of this manual to determine the appropriate design year for
the project.
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2.5.1.4 Speed Studies
Speed studies provide an essential measure for evaluating highway geometry. T he speed
study results may also serve as the basis for selecting a design speed within the acceptable
range for the highway’s functional class (refer to Section 2.6.1 of this chapter for a
discussion of design speed). Consult Chapter 5, Section 5.2.4 of this manual for more
information on speed studies and terminology.
2.5.2 Terrain
The topography of the land traversed has an influence on the horizontal and vertical alignment
of a highway. For design purposes, variations in topography are categorized by terrain, utilizing
the definitions in AASHTO's A Policy on Geometric Design of Highways and Streets:
• Level Terrain - That condition where highway sight distances, as governed by both
horizontal and vertical restrictions, are generally long or could be made to be so without
construction difficulty or major expense.
• Rolling Terrain - That condition where the natural slopes consistently rise above and fall
below the road or street grade and where occasional steep slopes offer some restriction
to normal horizontal and vertical roadway alignment.
• Mountainous Terrain - That condition where longitudinal and transverse changes in the
elevation of the ground with respect to the road or street are abrupt and where benching
and side hill excavation are frequently required to obtain acceptable horizontal and
vertical alignment.
The terrain classifications pertain to the general character of a specific route corridor. The
minimum road segment length for establishing a terrain classification is generally 0.6 miles
2.5.3 Special Routes
There are special routes designated to serve specific purposes as shown below
2.5.3.1 Strategic Highway Corridor Network (STRAHNET)
The United States Department of Defense has a program called Highways for National
Defense (HND) to ensure the mobility of United States Forces during national defense
operations. To support this program, a Strategic Highway Corridor Network (STRAHNET)
was established. The STRAHNET includes highways which are important to the United
States Strategic Defense Policy and which provide defense access, continuity, and
emergency capabilities for the movement of personnel, materials, and equipment in both
peacetime and wartime. This system consists of interstate and some non-interstate
highways. The minimum vertical clearance on these routes is 16’. Refer to Section 2 of the
Bridge Manual for information on the 16’ vertical clearance routes. [Note: sections of the
interstate system have been exempted from the vertical clearance requirements]. The
Highway Data Services Bureau of the Office of Technical Services maintains the
designation and map information concerning the STRAHNET system.
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2.5.3.2 Designated Qualifying and Access Highways
The 1982 Federal Surface Transportation Assistance Act (STAA) and the State 1990 T ruck
Safety Bill provided regulations concerning a system of reasonable access routes for special
dimension vehicles. Minimum travel lane widths of 12’ must be provided along Desig nated
Qualifying Highways. Minimum travel lane widths of 10’ are required along Designated
Access Highways and for routes within 1 mile of Qualifying Highways. The Office of T r affic
Safety and Mobility maintains a listing of all designated highways in the publication Official
Description of Designated Qualifying and Access Highways in New York State.
2.5.3.3 Bicycle Routes
Bicycle routes are a system or network of roads, streets, paths or ways that are open to
bicycle travel and that have been designated by the jurisdiction(s) having authority with
appropriate directional and informational route markers (with or without a specific bicycle
route number). Established bicycle routes should provide for continuous routing between
logical termini. The surface treatments and lane or shoulder widths required are e specially
important to assure the usability of designated bicycle routes. Refer to Chapter 17 of this
manual for further guidance.
2.5.3.4 National Highway System (NHS)
This system was established after passage of the Intermodal Surface Transportation
Efficiency Act (ISTEA) of 1991 and was approved by Congress in 1995. The NHS is
separate and distinct from the functional classification system. The NHS consists of
interconnected urban and rural highways and arterials (including toll facilities) which serve
major population centers, international border crossings, ports, airports, public transportation
facilities, other intermodal transportation facilities, and other major travel destinations; meet
national defense requirements; or serve interstate and interregional travel. Although limite d
in number, there are segments of local highways and rural minor collectors that are
classified as part of the NHS. All routes on the Interstate System are a part of the National
Highway System. A maps of the NHS routes in New York State be viewed on FHWA’s
website at
https://www.fhwa.dot.gov/planning/national_highway_system/nhs_maps/new_york/index.cf
m. This information can also be found on the Highway Data Services Bureau’s Roadway
Inventory System Viewer at https://www.dot.ny.gov/risviewer.
Design criteria for segments on the NHS follow the AASHTO’s A Policy on Geometric
Design of Highways and Streets, 2018. In general, these standards do not use construction
cost or other constraints as a major influence in the criteria.
Title 23 USC 109 allows states to establish design criteria for highways and streets that are
not part of the NHS. This allows states to establish criteria that reduce project costs and/or
the need for numerous nonstandard features on lower classification highways so that the
overall system can be improved using practical criteria. This chapter establishes non-NHS
design criteria for collectors, arterials, local roads, and local urban streets based on the
2R/3R design criteria values, which have been shown to cost-effectively improve safety.
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Refer to Chapter 7 of this manual for more information on the basis for the 2R/3R design
criteria values.
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2.6 CRITICAL DESIGN ELEMENTS
The eleven (11) items discussed in this section are defined as the critical design elements.
Usually, minimum or maximum values are specified for these elements.
2.6.1 Design Speed
Design speed is a speed established to determine the various geometric design features of the
roadway. The design speed should be a logical one with respect to the functional classification
of highway, anticipated off-peak 85th percentile speed, topography, the adjacent land use, modal
mix, and any planned improvements for the facility, including future projects on adjacent
segments. Once established, many of the critical elements of the highway are related to the
design speed.
There are important differences between the design criteria applicable to low- and high-speed
designs. AASHTO’s A Policy on Geometric Design of Highways and Streets, defines the upper
limit for low-speed at 45 mph and the lower limit for high-speed at 50 mph (i.e., low-speed < 45
mph & high speed > 50 mph). Project design speeds are to be rounded to the near est 5 mph
value and should, therefore, fall within one of these two categories.
2.6.1.1 Establishing a Design Speed
The design speed is either: maximum functional class speed or a speed based on the
anticipated (post-construction) off-peak 85th percentile speed within the range of speeds
shown under Section 2.7.X.Y. Refer to Chapter 5, Section 5.2 to determine of the off-peak
85th percentile speed.
The Regional Traffic Engineer should be consulted while determining the design speed that
will be used for selection of the other critical design elements. For freeways, the design
speed shall equal or exceed the regulatory speed limit in every case. The Deputy Chief
Engineer (Design) must approve urban design speeds more than 10 MPH over the
proposed regulatory speed in Urban Core areas. (Refer to Section 2.7.1.1 for a definition of
Urban Core areas). Scoping documents, design approval documents, etc., should contain
the basis for the design speed. The anticipated off-peak 85th percentile speed is to be based
on:
• Existing off-peak 85th Percentile Speed - Refer to Section 2.5.1.4 of this chapter and
Chapter 5, Section 5.2.4 of this manual for definitions and acceptable methods. For new
facilities, the anticipated off-peak 85th percentile speed may be based on the speeds of
facilities with similar classifications, geometry, and traffic characteristics.
• Improvements - Since speeds often increase when there is a new pavement surface,
and when geometric improvements are made, engineering judgment should be
exercised in determining the reasonableness and applicability of using an existing off-
peak 85th percentile speed that is below the maximum functional class speed. Where the
85th percentile speed is above the maximum functional class speed, the maximum
functional class speed shall be used as the design speed.
• Traffic Calming - Refer to Chapter 25 of this manual for requirements and guidance.
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