Attachment 9 - Roadway Design Manual.pdf

ROADWAY DESIGN

MANUAL

BDC19MR-02

NJDOT Roadway Design Manual i

Table of Contents

Table of Contents

Section 1 - Introduction

1.1 Introduction

1.2 Policy on Use of AASHTO Standards

1.3 Reference Publications

Section 2 - General Design Criteria

2.1 General

2.2 Highway Classification

2.2.1 General

2.2.2 Principal Arterial Highways

2.2.3 Minor Arterial Highways

2.2.4 Collector Roads

2.2.5 Local Roads

2.3 Design Controls

2.3.1 General

2.3.2 Primary Controls

2.3.3 Secondary Controls

Section 3 - Definitions and Terminology

3.1 General

3.2 Cross-Section Terminology

3.3 Roadway Design Terms

3.4 Pedestrian Design Terms

3.5 Bicycle Design Terms

Section 4 - Basic Geometric Design Elements

4.1 General

4.2 Sight Distances

4.2.1 General

4.2.2 Passing Sight Distance

4.2.3 Stopping Sight Distance

4.2.4 Stopping Sight Distance on Vertical Curves

4.2.5 Stopping Sight Distance on Horizontal Curves

4.3 Horizontal Alignment

4.3.1 General

4.3.2 Superelevation

4.3.3 Curvature

4.4 Vertical Alignment

4.4.1 General

4.4.2 Position with Respect to Cross Section

4.4.3 Separate Grade Lines

4.4.4 Standards for Grade

4.4.5 Vertical Curves

4.4.6 Heavy Grades

4.4.7 Coordination with Horizontal Alignment

4.5 Climbing Lane

4.6 Through Lane Transition

Section 5 - Major Cross Section Elements

5.1 General

5.2 Pavement

5.2.1 Surface Type

5.2.2 Cross Slope

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5.3 Lane Widths

5.4 Shoulders

5.4.1 General

5.4.2 Width of Shoulders

5.4.3 Cross Slope

5.4.4 Intermittent Shoulders or Turnouts

5.5 Roadside or Border

5.5.1 General

5.5.2 Width

5.5.3 Fencing

5.6 Curbing

5.6.1 General

5.6.2 Types of Curb

5.6.3 Placement of Curb

5.6.4 Curb Height

5.7 Sidewalk

5.7.1 General

5.7.2 Pedestrian Needs

5.7.3 Sidewalk Design

5.7.4 Public Sidewalk Curb Ramp

5.8 Driveways

5.8.1 Pedestrian Accommodations at Driveways

5.9 Medians

5.9.1 General

5.9.2 Islands, Medians, and Pedestrian Refuges

5.9.3 Median Fencing on Land Service Highways

5.10 Standard Typical Sections

5.11 Bridges and Structures

5.11.1 General

5.11.2 Lateral Clearances

5.11.3 Vertical Clearance

5.12 Traffic Stripes and Traffic Markings

5.13 Raised Pavement Markers

5.14 Rumble Strips

5.14.1 General

5.14.2 Shoulder Rumble Strips

5.14.3 Centerline Rumble Strips

Section 6 - At Grade Intersections

6.1 General

6.2 General Design Considerations

6.2.1 Capacity Analysis

6.2.2 Spacing

6.2.3 Alignment and Profile

6.2.4 Cross Section

6.3 Sight Distance

6.3.1 General

6.3.2 Sight Distance for Bicycle Facilities

6.3.3 Stop Control on Cross Street

6.3.4 Yield Control

6.3.5 Sight Distance at Signalized Intersections

6.4 Vehicular Turning Movements

6.4.1 General

6.4.2 Design Vehicles

6.4.3 Turning Radii at Unchannelized Intersections

6.5 Channelization

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Table of Contents

6.5.1 General

6.5.2 Islands

6.5.3 Auxiliary Lanes

6.5.4 Median Openings

6.5.5 Median Openings for Emergency Vehicles

6.6 Median Left-Turn Lane

6.6.1 General

6.6.2 Lane Width

6.6.3 Length

6.7 Continuous Two-Way Left-Turn Median Lane

6.7.1 General

6.7.2 Lane Width

6.7.3 Cross Slope

6.8 Jughandles

6.8.1 General

6.8.2 Ramp Width

6.8.3 Access Control

6.8.4 Standard Jughandle Designs

6.8.5 Superelevation and Cross Slope

6.8.6 Crosswalks, Pavement Markings and Bike Lanes

6.9 Other Considerations

6.9.1 Parking Restrictions at Intersections

6.9.2 Lighting at Intersections

6.10 Bus Turnouts

6.10.1 Introduction

6.10.2 Location Criteria

6.10.3 Other Considerations

6.10.4 Bus Turnout Design Criteria

Section 7 - Interchanges

7.1 General

7.2 Warrants for Interchanges

7.2.1 Freeways and Interstate Highways

7.2.2 Other Highways

7.3 Interchange Types

7.3.1 General

7.4 Interchange Design Elements

7.4.1 General

7.4.2 Spacing

7.4.3 Sight Distance

7.4.4 Alignment, Profile and Cross Section

7.5 Ramps

7.5.1 General

7.5.2 Ramp Capacity

7.5.3 Design Speed

7.5.4 Grades (Profile)

7.5.5 Sight Distance

7.5.6 Widths

7.5.7 Location of Ramp Intersection on Cross Road

7.6 Superelevation and Cross Slope for Interchange Ramps

7.7 Freeway Entrances and Exits

7.7.1 Basic Policy

7.7.2 Ramp Terminals

7.7.3 Distance between Successive Exits

7.7.4 Auxiliary Lane Lengths

7.7.5 Curbs

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7.8 Additional Lanes

7.9 Lane Reduction

7.10 Route Continuity

7.11 Weaving Sections

7.12 Access Control

7.13 Bicycle and Pedestrian Accommodations

7.14 Collector – Distributor Roads

Section 8 -Guide Rail and Median Barriers

8.1 Introduction

8.2 Guide Rail Warrants

8.2.1 General

8.2.2 How Warrants are Determined

8.2.3 Clear Zone

8.2.4 Warrants

8.3 Dimensional Characteristics

8.3.1 Guide Rail Offset

8.3.2 End Treatments

8.3.3 Roadside Recovery Area

8.3.4 Approach Length of Need (L.O.N.)

8.3.5 Nonvegetative Surface Under Guide Rail

8.3.6 Sidewalks

8.3.7 Underground Structures

8.3.8 Guide Rail Details

8.3.9 General Comments

8.4 Median Barrier

8.4.1 Warrants for Median Barriers

8.4.2 Median Barrier Type

8.4.3 Median Barrier Location

8.4.4 Emergency and Maintenance U-Turns

8.4.5 Median Barrier End Treatments

8.5 Diversionary Roads (Road Closure with Diversion)

Section 9 - Crash Cushions

9.1 Introduction

9.2 Selection Guidelines

9.2.1 General

9.2.2 Dimensions of the Obstruction

9.2.3 Space Requirement

9.2.4 Geometrics of the Site

9.2.5 Physical Conditions of the Site

9.2.6 Redirection Characteristics

9.2.7 Design Speed

9.2.8 Foundations

9.2.9 Backup Structure Requirements

9.2.10 Anchorage Requirements

9.2.11 Flying Debris Characteristics

9.2.12 Initial Cost

9.2.13 Maintenance

9.3 Design Procedure

9.3.1 Inertial Barriers

9.3.2 Compressive Barriers

9.4 Product Information

Section 10 - Drainage

10.1 General Information

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10.1.1 Introduction

10.1.2 Definitions and Abbreviations

10.1.3 Design Procedure Overview

10.2 Drainage Policy

10.2.1 Introduction

10.2.2 Stormwater Management and Non-Point Source Pollution Control

10.2.3 Allowable Water Surface Elevation

10.2.4 Recurrence Interval

10.2.5 Increasing Fill Height Over Existing Structures

10.2.6 Regulatory Compliance

10.2.7 Flood Hazard Area (Stream Encroachment)

10.2.8 Soil Erosion and Sediment Control

10.3 Hydrology

10.3.1 Introduction

10.3.2 Selection of Hydrologic Methods

10.3.3 Rational Formula

10.3.4 US Natural Resources Conservation Service (NRCS) Methodology

10.3.5 Time of Concentration (Tc)

10.3.6 Flood Routing

10.4 Channel Design

10.4.1 Introduction

10.4.2 Channel Type

10.4.3 Site Application

10.4.4 Channel Design Procedure

10.5 Drainage of Highway and Pavements

10.5.1 Introduction

10.5.2 Runoff Collection and Conveyance System Type

10.5.3 Types of Inlets Used by NJDOT

10.5.4 Flow in Gutters (Spread)

10.5.5 Limits of Spread

10.5.6 Inlets

10.5.7 Capacity of Gutter Inlets on Grade

10.5.8 Capacity of Grate Inlets at Low Points

10.5.9 Location of Inlets

10.5.10 Spacing of Inlets

10.5.11 Depressed Gutter Inlet

10.5.12 Snow Melt Control

10.5.13 Alternative Runoff Collection Systems

10.6 Storm Drains

10.6.1 Introduction

10.6.2 Criteria for Storm Drains

10.6.3 Storm Sewer Design

10.6.4 Preliminary Pipe Size

10.6.5 Hydraulic Grade Line computations

10.7 Median Drainage

10.7.1 Introduction

10.7.2 Median Inlet Type

10.7.3 Median Design Criteria - Continuous Grade

10.7.4 Procedure for Spacing Median Drains

10.8 Culvert Design

10.8.1 Introduction

10.8.2 Culvert Types

10.8.3 Culvert Location

10.8.4 Culvert Selection

10.8.5 Culvert Hydraulics

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10.8.6 Culvert End Structures

10.8.7 Flood Routing at Culverts

10.8.8 Aquatic Species (Including Fish) Passage

10.9 Conduit Outlet Protection

10.9.1 Riprap Size and Apron Dimensions

10.9.2 Energy Dissipators

10.10 Reset Castings - Manholes and Inlets

10.10.1 Reset Castings and Construction Practices

10.10.2 Extension Rings and Frames

10.10.3 Extension Rings - Manholes

10.10.4 Extension Frames - Inlets

10.10.5 Ramping

10.11 Stormwater Management

10.11.1 Introduction

10.11.2 Methodology

10.11.3 Stormwater Management Facility Locations

10.11.4 Stormwater Management Facility Design Features

10.11.5 Stormwater Management Facility Maintenance

10.12 Water Quality

10.12.1 Introduction

10.12.2 Methodology

10.12.3 Water Quality Treatment Facilities and Design

10.12.4 Scour Considerations

10.13 Sample Hydrologic and Hydraulic Calculations

10.13.1 Sample Hydraulic Calculations

10.13.2 Sample Hydrologic Calculations

Section 11 - Highway Lighting Systems

11.1 General

11.2 Reference Publications

11.3 General Design Criteria

11.3.1 Warrants for Highway Lighting

11.3.2 Selection of Types of Highway Lighting

11.3.3 Level of Illuminance

11.3.4 Uniformity of Illuminance

11.3.5 Basis for Lighting Calculation

11.3.6 Lighting Calculations

11.3.7 Underdeck Lighting

11.3.8 Conduit

11.3.9 Cables and Wire

11.3.10 Junction Boxes and Foundations

11.3.11 Incoming Service

11.3.12 Load Center Designations

11.3.13 Circuitry and Other Considerations

11.4 Sign Lighting

11.5 Existing Highway Lighting System

11.6 Temporary Lighting

11.6.1 Designing the Temporary Lighting

11.7 Highway Lighting Plans

11.8 Lighting at Intersections

11.9 Non-Functional Historic Replica Lighting

11.10 Functional Historic Lighting

11.11 Mid-Block Pedestrian Crossing

11.12 Roundabout Lighting

11.13 Pedestrian Crosswalks

11.14 Light Trespass from Off-Site Development

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11.15 Voltage Drop Calculation Method

Section 12 - Traffic Signal Design

12.1 General

12.2 Reference Publications

12.3 General Design Criteria

12.3.1 Warrants for Traffic Signals

12.3.2 Traffic Signal Design –“TS” Plan - General

12.3.3 Traffic Signal Timing and Operation - General

12.3.4 Pedestrian Timing Considerations - General

12.3.5 Pre-Emption

12.3.6 Temporary Traffic Signals

12.3.7 Traffic Signal Controller

12.3.8 Traffic Signal Standards

12.3.9 Traffic Signal Indications

12.3.10 Intersection Lighting

12.3.11 Conduits

12.3.12 Cables and Wires

12.3.13 Vehicular Detection

12.3.14 Junction Boxes

12.3.15 Incoming Service

Section 13 - Ground Mounted Sign Supports

13.1 Introduction

13.2 Small Highway Signs

13.3 Large Highway Signs

13.3.1 Breakaway Sign Supports

13.3.2 Non - Vegetative Surface under Overhead Signs and Large Ground

Mounted Signs

Section 14 - Traffic Control Plans and Details

14.1 Introduction

14.2 General

14.3 Traffic Control and Staging Plans

14.4 Traffic Impact Report

14.5 Development of Traffic Control Plan Design Parameters

14.6 Latex Traffic Stripes and Traffic Markings

14.7 Lane and Roadway Closures

14.7.1 Lane Closures

14.7.2 Total Roadway Closures

14.7.3 Center/Interior Lane Closures

14.7.4 Alternate Traffic Routes

14.7.5 Temporary Emergency Pull-Off

14.8 Construction Barrier Curb

14.8.1 Introduction

14.8.2 Warrants

14.8.3 Applications

14.9 Construction Barrier Curb, Moveable System

14.9.1 Warrants

14.9.2 Applications

14.9.3 Safety and Cost Considerations

14.10 Nighttime Construction

14.11 Construction Details

14.11.1 Crash Cushions

14.11.2 Signs

14.11.3 Guide Rail

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14.12 Utilities

14.13 Quantities

14.14 Installation and Removal Sequence for Work Zone Traffic Control

14.15 Traffic Control Plan Submission Requirements

14.15.1 Initial Submission: Investigate project site specific conditions and Prepare Preliminary Staging Plans:

14.15.2 Final Submission: Prepare Final Traffic Control Plans and Staging Plans:

14.16 Quality Control Checklist for Designers

Section 15 - Traffic Calming

15.1 Introduction

15.1.1 General

15.1.2 Objective

15.1.3 Definition

15.1.4 References

15.1.5 Principles

15.2 General Traffic Calming Design Controls

15.2.1 Design Speed

15.2.2 Clear Zone and Streetscape

15.2.3 Signs and Markings

15.3 Traffic Calming Design Standards

15.3.1 Volume Control Devices

15.3.2 Speed Control Devices – Vertical Speed Table

15.3.3 Speed Control Devices - Horizontal

15.3.4 Other Devices

15.3.5 Combination Treatments

BDC19MR-01

NJDOT Roadway Design Manual 1-1

Introduction

Section 1 - Introduction

1.1 Introduction

This manual presents the current Department guidelines pertaining to roadway design on the State Highway system (www.state.nj.us/transportation/refdata/sldiag/). It provides a means of developing uniformity and safety in the design of a highway system consistent with the needs of the motoring and non-motoring users.

Regarding controlling design elements (CDE’s), it is recognized that situations occur where good engineering judgment will dictate deviation from the current Department design guidelines. Any such deviations from the design guidelines relative to the(CDE’s) will require an approved design exception.

See the NJDOT Design Exception Manual for specific CDE’s relative to the appropriate

Type of Design Exception:

• Design Exception Type 1 (Design Speeds ≥ 50 mph)

• Design Exception Type 2 (Design Speeds < 50 mph)

• Design Exception Type 3 Major Access/Developer Projects (All Designs Speeds)

(Also refer to the Design Exception Manual for exemptions to the Design Exception

Process.)

The guidelines contained in this manual, other than CDE’s, are primarily informational or guidance in character and serve to assist the engineer in attaining good design.

Deviations from this information or guidance do not require a design exception.

It is not the intent of this manual to reproduce all the information that is adequately covered by textbooks and other publications which are readily available to designers and technicians.

This manual, when used in conjunction with engineering knowledge of highway design and good judgment, should enable the designer to perform their job more efficiently.

The geometric design of streets and highways not on the State Highway system should conform to the standards as indicated in the current AASHTO – A Policy on

Geometric Design of Highways and Streets. The design of traffic barriers and drainage systems shall conform to the NJDOT Roadway Design Manual.

1.2 Policy on Use of AASHTO Standards

The American Association of State Highway and Transportation Officials (AASHTO) has published policies on highway design practice. These are approved references to be used in conjunction with this manual. AASHTO policies represent nationwide standards that do not always satisfy New Jersey conditions. When standards differ, the instructions in this manual shall govern except on Interstate highways. The geometric design of the Interstate System, as a minimum, shall comply with the standards presented in the AASHTO publications; but the design of traffic barriers shall conform to the NJDOT Roadway Design Manual.

http://www.state.nj.us/transportation/refdata/sldiag/

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Introduction

1.3 Reference Publications

• Note: If there is a date given for the publication and a revised edition exists, use the current FHWA approved edition.

A. American Association of State Highway and Transportation Officials (AASHTO), American Association of State Highway Officials (AASHO)

• AASHTO – A Policy on Geometric Design of Highways and Streets, 2011

• AASHTO – A Policy on Design Standards - Interstate System, 2005

• AASHTO – Roadside Design Guide, 2011

• AASHTO – A Guide for the Development of Rest Areas on Major

Arterials and Freeways, 2001

• AASHTO – Guide for the Development of Bicycle Facilities,2012

• AASHTO – An Informational Guide for Roadway Lighting, (1984)

• AASHTO – Guide for the Planning, Design and Operation of Pedestrian Facilities, 2004

• AASHO – Highway Definitions, 1968

• AASHO – A Policy on U-Turn Median Openings on Freeways, 1960

B. Transportation Research Board (TRB)

• TRB – Highway Capacity Manual, (2010)

C. Federal Highway Administration (FHWA)

• FHWA – National Transportation Communications for ITS Protocol http://www.ntcip.org/info/

• FHWA – Federal-Aid Policy Guide (FAPG), (1991 with Updates)

• FHWA – Roundabouts: An Informational Guide, (2000), Publication No. FHWA-RD-

00-067

• FHWA – Roadway Lighting Handbook, (1978 and Addendums)

• FHWA – Pedestrian Facilities Users Guide: Providing Safety and Mobility Publication

No. FHWA-RD-01-102 (1999)

• System Engineering Guidebook for ITS, (2007), http://www.fhwa.dot.gov/cadiv/segb/

• FHWA – Manual on Uniform Traffic Control Devices, (2009)

D. Institute of Transportation Engineers (ITE)

• ITE – Alternative Treatments for At-Grade Pedestrian Crossings, (2001)

E. Illuminating Engineering Society North America (IESNA)

• IESNA – Lighting Handbook, 9th (2000)

F. National Fire Protection Association

• National Electrical Code (NEC), (2008)

• National Electrical Code (NEC) Handbook, (2008)

G. New Jersey Department of Transportation (NJDOT)

• NJDOT – Bicycle Compatible Roadways and Bikeways: Planning and Design

Guidelines, (1996)

• NJDOT – Pedestrian Compatible Planning and Design Guidelines, (1996)

• NJ Statewide ITS Architecture, (2005)

• 2017 State of New Jersey: Complete Streets Design Guide

H. National Committee on Uniform Traffic Laws and Ordinances (NCUTLO) http://www.ntcip.org/info/ http://www.fhwa.dot.gov/cadiv/segb/

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Introduction

• NCUTLO – Uniform Vehicle Code, (2000)

I. United States Access Board

• ADA Access Board – Recommendations for Accessibility Guidelines: Recreational

Facilities and Outdoor Developed Areas, (Published in the Federal Register July 23, 2004 and as amended through May 7, 2014)

J. Department of Justice

• 2010 Standards for Titles II and III Facilities: 2004 ADAAG.

K. Public Rights-of-way Access Advisory Committee

• Special Report: Accessible Public Rights-of-Way Planning and Design for Alterations

(2007)

L. Miscellaneous

• Chicagoland Bicycle Federation BLOS/BCI Form – http://rideillinois.org/advocacy/bikeped-level-of-service-measures-and-calculators/

- Calculator for Bicycle Level of Service and Bicycle Compatibility Index http://rideillinois.org/advocacy/bikeped-level-of-service-measures-and-calculators/

BDC16MR-02

NJDOT Roadway Design Manual 2-1

General Design Criteria

Section 2 - General Design Criteria

2.1 General

Geometric design is the design of the visible dimensions of a highway with the objective of forming or shaping the facility to the characteristics and behavior of drivers, vehicles, and traffic. Therefore, geometric design deals with features of location, alignment, profile, cross section, intersection, and highway types.

2.2 Highway Classification

2.2.1 General

Highway classification refers to a process by which roadways are classified into a set of sub-systems, described below, based on the way each roadway is used. Central to this process is an understanding that travel rarely involves movement along a single roadway. Rather each trip or sub-trip initiates at a land use, proceeds through a sequence of streets, roads and highways, and terminates at a second land use.

The highway classification process is required by federal law. Each state must assign roadways into different classes in accordance with standards and procedures established by the Federal Highway Administration. Separate standards and procedures have been established for rural and urban areas. For a further description of the classification process, see USDOT, FHWA, Highway Functional Classification:

Concepts, Criteria and Procedures.

2.2.2 Principal Arterial Highways

Principal arterial highways form an inter-connected network of continuous routes serving corridor movements having the highest traffic volumes and the longest trip lengths. In rural areas, travel patterns should be indicative of substantial statewide or interstate travel. In urban areas, principal arterials should carry a high proportion of total urban area travel on a minimum of mileage.

The principal arterial highway system is stratified into the following two sub-systems:

• Interstate system - all presently designated routes of the Interstate System.

• Other principal arterials - all non-Interstate principal arterials.

"Other principal arterial" highways may be freeways, expressways or land service highways. However, because of the function of principal arterial highways, the concept of service to abutting land should be subordinate to the provision of travel service to major traffic movements. For facilities within the subclass of other principal arterials in urban areas, mobility is often balanced against the need to provide direct access as well as the need to accommodate pedestrians, bicyclists, and transit users. Where permitted, direct access to abutting property should be carefully regulated by license.

No absolute right exists for access to a principal highway, and the rights of the traveling public to a safe and efficient roadway must be guaranteed. However, abutting property owners do have a right of reasonable access to the system of highways, unless such right has been acquired by the State.

Except for toll roads, most "other principal arterials" are included in the Federal consolidated primary (FAP) highway system.

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General Design Criteria

2.2.3 Minor Arterial Highways

Minor arterial highways interconnect with and augment the principal highway system.

In urban areas, minor arterial highways are usually included in the Federal-aid urban system (FAUS), and serve trips of moderate length at a somewhat lower level of travel mobility. Access to abutting property should be minimized to facilitate traffic flow and safety. In rural areas, minor arterial highways will usually be included in the Federal consolidated primary (FAP) system, and serve trip lengths and travel densities greater than those served by collector roads. Rural minor arterials should provide relatively high overall travel speeds, with minimum interference to through movements consistent with the context of the project area and considering the range or variety of users. Because of the high speeds, access to abutting property should be either controlled or carefully regulated.

2.2.4 Collector Roads

Collector roads primarily serve trips of intracounty rather than statewide importance.

Travel speeds and volumes are less than on arterial roadways, but are still high relative to local roads. These roads provide for both land access and traffic circulation.

In urban areas, these roads connect neighborhoods or other districts with the arterial system, and will usually be part of the Federal-aid urban system (FAUS). In rural areas, these roads may be subclassified into two groups:

• Major collectors - Serve important intracounty traffic corridors and provide service to major county traffic generators. These roads will usually be included in the Federal-aid secondary (FAS) system.

• Minor collectors - Serve smaller places and towns and connect locally important traffic generators. These roads usually will not be on a Federal-aid system.

2.2.5 Local Roads

The local street and road system constitutes all roads not included in the higher classifications. These streets and roads provide direct access to abutting land and permit access to the roads of higher classification. They offer the lowest level of mobility. Service to through traffic movement usually is deliberately discouraged, especially in urban areas. The local road system contains the large majority of all roadway mileage in a state, but only a small percentage of total traffic. For example, in New Jersey local roads include 72 percent of total road mileage, but only 16 percent of total vehicular miles traveled.

2.3 Design Controls

2.3.1 General

The location and geometric design of highways are affected by numerous factors and controlling features. These may be considered in two broad categories as follows:

A. Primary Controls

• Highway Classification

• Topography and Physical Features

• Traffic

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General Design Criteria

B. Secondary Controls

• Design Speed

• Design Vehicle

• Capacity

2.3.2 Primary Controls

A. Highway Classification

Separate design standards are appropriate for different classes of roads, since the classes serve different types of trips and operate under different conditions of both speed and traffic volume. The design of streets and highways on the State highway system should conform to the guidelines as indicated in this manual. In special cases of restrictive or unusual conditions, it may not be practical to meet these guide values. For detailed descriptions of the various guide values, please refer to the appropriate Sections of this Manual.

B. Topography and Physical Features

The location and the geometric features of a highway are influenced to a large degree by the topography, physical features, and land use of the area traversed. The character of the terrain has a pronounced effect upon the longitudinal features of the highway, and frequently upon the cross sectional features as well. Geological conditions may also affect the location and the geometrics of the highway. Climatic, soil and drainage conditions may affect the profile of a road relative to existing ground.

Man-made features and land use may also have considerable effect upon the location and the design of the highway. Industrial, commercial, and residential areas will each dictate different geometric requirements.

C. Traffic

The traffic characteristics, volume, composition and speed, indicate the service for which the highway improvement is being made and directly affects the geometric features of design.

The traffic volume affects the capacity, and thus the number of lanes required. For planning and design purposes, the demand of traffic is generally expressed in terms of the design-hourly volume (DHV), predicated on the design year. The design year for new construction and reconstruction is to be 20 years beyond the anticipated date of

Plans, Specifications and Estimate (PS&E), and 10 years beyond the anticipated date of PS&E for resurfacing, restoration and rehabilitation projects.

The composition of traffic, i.e., proportion of trucks and buses, is another characteristic which affects the location and geometrics of highways. Types, sizes and load-power characteristics are some of the aspects taken into account.

The following definitions apply to traffic data elements pertinent to design.

ADT Average Daily Traffic - The total volume during a given time period greater than one day but less than one year divided by the number of days actually counted.

AADT Average Annual Daily Traffic - The total yearly volume in both directions of travel divided by 365 days.

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General Design Criteria

DHV Design-Hourly Volume - Normally estimated as the 30th highest hour two-way traffic volume for the design year selected.

K Ratio of DHV to ADT, expressed as a percent.

D The directional distribution of traffic during the design hour. It is the one-way volume in the predominant direction of travel expressed as a percentage of DHV.

T The proportion of trucks, exclusive of light delivery trucks, expressed as a percentage of DHV.

V Design Speed – Expressed in mph.

2.3.3 Secondary Controls

A. Design Speed

"Design Speed" is a selected speed used to determine the various design features of the roadway.

The assumed design speed should be a logical one with respect to topography, anticipated operating speed, the adjacent land use, the presence of bicycle and pedestrian accommodations, and the functional classification of the highway. Except for local streets where speed controls are frequently included intentionally, every effort should be made to use as high a design speed as practicable to attain a desired degree of safety, mobility and efficiency within the constraints of environmental quality, economics, aesthetics and social or political impacts. Once the design speed is selected, all of the pertinent features of the highway should be related to it to obtain a balanced design. Above minimum design values should be used, where practical. On lower speed facilities, use of above-minimum design criteria may encourage travel at speeds higher than the design speed. Some design features, such as curvature, superelevation, and sight distance are directly related to and vary appreciably with design speed. Other features, such as widths of lanes and shoulders, and clearances to walls and rails, are not directly related to design speed, but they affect vehicle speeds. Therefore, wider lanes, shoulders, and clearances should be considered for higher design speeds. Thus, when a change is made in design speed, many elements of the highway design will change accordingly.

Since design speed is predicated on the favorable conditions of climate and little or no traffic on the highway, it is influenced principally by:

• Character of the terrain;

• Extent of man-made features;

• Economic considerations (as related to construction and right-of-way costs).

These three factors apply only to the selection of a specific design speed within a logical range pertinent to a particular system or classification of which the facility is a part.

The design speed (mph) as it relates to the posted speed (mph) is shown below:

NJDOT Roadway Design Manual 2-5

General Design Criteria

Table 2-1

Design Speed vs. Posted Speed

Posted

Speed

Design Speed *

Existing

Highways

New Highways or Alignment

20 mph

25 mph

30 mph

35 mph

40 mph

45 mph

50 mph

55 mph

25 mph

30 mph

35 mph

40 mph

45 mph

50 mph

55 mph

60 mph

30 mph

35 mph

40 mph

45 mph

50 mph

55 mph

60 mph

65 mph

* Generally, for freeways and the Interstate system, the design speed shall be 70 mph for either column shown in Table 2-1. But in certain urban areas, the

Interstate highway or freeway was designed at 60 mph. Therefore the design speed shall be 60 mph in either column for these areas. Refer to the Traffic

Calming Section of this manual for speeds used in traffic calming areas.

B. Design Vehicle

The physical characteristics of vehicles and the proportions of the various size vehicles using the highways are positive controls in geometric design. A design vehicle is a selected motor vehicle, the weight, dimensions and operating characteristics of which are used to establish highway design controls to accommodate vehicles of a designated type. The symbols and dimensions of design vehicles are shown in Table

2-2.

Table 2-2

Design Vehicles (Dimensions in feet*)

Design Vehicle Wheel

Base

Overhang Overall

Type Symbol Front Rear Length Width

Passenger Car P 11.0 3.0 5.0 19.0 7.0

Single Unit Truck SU-30 20.0 4.0 6.0 30.0 8.0

Single Unit Truck

(three-axle)

SU-40 25.0 4.0 10.5 39.5 8.0

Single Unit Bus BUS-40 25.3 6.3 9.0 40.5 8.5

Articulated Bus A-BUS 22+ 19.4 = 41.4 8.6 10.0 60.0 8.5

Semitrailer

Intermediate

WB-40 12.5+25.5 = 38 3.0 4.5 45.5 8.0

Semitrailer Large WB-50 14.6+35.4 = 50 3.0 2.0 55 8.5

Semitrailer

Interstate

WB-62 19.5+41.0 = 60.5 4.0 4.5 69.0 8.5

NJDOT Roadway Design Manual 2-6

General Design Criteria

“Double Bottom”

Semitrailer

WB-67D

11+23+10+22.5 =

66.5

2.3 3.0 72.3 8.5

Delivery Truck DL 16 3 5 24 7.5

Source: A Policy on Geometric Design of Highways and Streets, AASHTO

* Design vehicle dimensions are intended for use in the design of roadways and do not define the legal vehicle dimensions in the State.

* The delivery truck is based on a typical USPS, UPS or FedEx truck.

C. Capacity

1. General

The term "capacity" is used to express the maximum number of vehicles which have a reasonable expectation of passing over a section of a lane or a roadway during a given time period under prevailing roadway and traffic conditions.

However, in a broad sense, capacity encompasses the relationship between highway characteristics and conditions, traffic composition and flow patterns, and the relative degree of congestion at various traffic volumes throughout the range from light volumes to those equaling the capacity of the facility as defined above.

Highway capacity information serves three general purposes:

a. For transportation planning studies to assess the adequacy or sufficiency of existing highway networks to current traffic demand, and to estimate when, in time, projected traffic demand, may exceed the capacity of the existing highway network or may cause undesirable congestion on the highway system.

b. For identifying and analyzing bottleneck locations (both existing and potential), and for the evaluation of traffic operational improvement projects on the highway network.

c. For highway design purposes.

2. Level of Service (LOS)

The level of service concept places various traffic flow conditions into 6 levels of service. These levels of service, designated A through F, from best to worst, cover the entire range of traffic operations that may occur.

The factors that may be considered in evaluating level of service include the following.

• Speed and travel time

• Traffic interruptions or restrictions

• Freedom to maneuver

• Safety

• Driving comfort and convenience

• Economy

However, in a practical approach to identifying the level of service, travel time and the ratio of demand volume to capacity are commonly used.

NJDOT Roadway Design Manual 2-7

General Design Criteria

In general, the various levels of service would have the following characteristics:

Level of Service A is free flow, with low volumes and high speeds. Traffic density is low, with speeds controlled by driver desires, speed limits, and physical roadway conditions. There is little or no restriction in maneuverability due to presence of other vehicles. Drivers can maintain their desired speed with little or no delay.

Level of Service B is in the zone of stable flow, with operating speeds beginning to be restricted somewhat by traffic conditions. Drivers still have reasonable freedom to select their speed and lane of operation. Reductions in speed are not unreasonable, with a low probability of traffic flow being restricted. The lower limit (lowest speed, highest volume) of this level of service has been associated with service volumes used in the design of rural highways.

Level of Service C is still in the zone of stable flow, but speeds and maneuverability are more closely controlled by the higher volumes. Most of the drivers are restricted in their freedom to select their own speed, change lanes, or pass. A relatively satisfactory operating speed is still obtained, with service volumes perhaps suitable for urban design practice.

Level of Service D approaches unstable flow, with tolerable operating speeds being maintained though considerably affected by changes in operating conditions. Fluctuations in volume and temporary restrictions to flow may cause substantial drops in operating speeds. Drivers have little freedom to maneuver, and comfort and convenience are low, but conditions can be tolerated for short periods of time.

Level of Service E cannot be described by speed alone, but represents operations at even lower operating speeds than in Level D, with volumes at or near the capacity of the highway. At capacity, speeds are typically, but not always, in the neighborhood of 25 mph; flow is unstable, and there may be stoppages of momentary duration.

Level of Service F describes forced flow operation at low speeds, where volumes are below capacity. These conditions usually result from queues of vehicles backing up from a restriction downstream. The section under study will be serving as a storage area during parts or all of the peak hour. Speeds are reduced substantially and stoppages may occur for short or long periods of time because of the downstream congestion. In the extreme, both speed and volume can drop to zero.

Reference is made to the Transportation Research Board, “Highway Capacity

Manual,” for a thorough discussion on the level of service concept.

3. Service Volume

For highway design purposes, the service volume is related to the "Level of

Service" selected for the proposed facility. (No service volumes are defined for

Level of Service F). Service volume is defined as the maximum rate of flow which may be accommodated under prevailing traffic and roadway conditions while still maintaining a quality of service appropriate to the indicated Level of

Service.

NJDOT Roadway Design Manual 2-8

General Design Criteria

The service volume varies with a number of factors, including:

• Level of service selected;

• Width of lanes;

• Number of lanes;

• Presence or absence of shoulders;

• Grades;

• Horizontal alignment;

• Operating speed;

• Lateral clearance;

• Side friction generated by parking, driveways, intersections, and interchanges;

• Volumes of trucks, buses, and recreational vehicles;

• Spacing and timing of traffic signals.

The objective in highway design is to create a highway of appropriate type with dimensional values and alignment characteristics such that the resulting service volume will be at least as great as the design volume, but not much greater as to represent extravagance or waste. More detailed data on service volume are available in the Transportation Research Board, “Highway Capacity Manual,” and AASHTO, “A Policy on Geometric Design of Highways and Streets”.

BDC15MR-01

NJDOT Roadway Design Manual 3-1

Definitions and Terminology

Section 3 - Definitions and Terminology

3.1 General

This section includes general terminology associated with the road cross-section and terms commonly used in highway design. Reference is made to “Highway Definitions,”

AASHTO, 1968.

3.2 Cross-Section Terminology

The elements of the road cross-section are illustrated in Figure 3-A and Figure 3-B and defined as follows:

1. Highway - A general term denoting a public way for purposes of vehicular travel, including the entire area within the right-of-way lines. Recommended usage in urban areas, highway, or street; in rural areas, highway or road.

2. Highway Section - The portion of the highway included between top of slopes in cut and the toe of slopes in fill.

3. Roadway - The portion of the highway, including shoulders, for vehicular use.

4. Traveled Way - The portion of the roadway provided for the movement of vehicles, exclusive of shoulders, auxiliary lanes, and bicycle lanes.

5. Median - The portion of a divided highway separating the traveled ways for traffic in opposite directions.

6. Shoulder - The portion of the roadway contiguous with the traveled way for accommodation of stopped vehicles for emergency use, and for lateral support of the base and surface courses. The shoulder may be used for bicycle travel where allowed. It may also be used by pedestrians in the absence of a sidewalk.

7. Surfaced Right Shoulder - That portion of the outside paved shoulder to provide all weather load support.

8. Surfaced Left Shoulder - The portion of the median shoulder paved to provide all weather load support.

9. Profile Line - The point for control of the vertical alignment. Also, normally the point of rotation for superelevated sections.

10. Pavement Cross Slope – Lateral slope across the pavement. See Section

5.2.2.

11. Shoulder Cross Slope – Lateral slope across the shoulder. See Section

5.4.3.

12. Base Course - The layer or layers of specified or selected material of designed thickness placed on a subbase or subgrade to support a surface course.

13. Subbase - The layer or layers of specified or selected material placed on a subgrade to support a base course.

NJDOT Roadway Design Manual 3-2

Definitions and Terminology

14. Surface Course - One or more layers of a pavement structure designed to accommodate the traffic load, the top layer of which resists skidding, traffic abrasion, and the disintegrating effects of climate.

15. Pavement Structure - The combination of subbase, base course and surface course placed on a subgrade to support the traffic load and distribute it to the roadbed.

16. Shoulder Surface Course

17. Shoulder Base Course

18. Subgrade - The top surface of the roadbed upon which the pavement structure and shoulders are constructed.

19. Original (Existing) Ground

20. Embankment (Fill)

21. Fill Slope

22. Cut Section

23. Cut Slope - Also called cut face.

24. Hinge Point (P.V.I.) - The intersection of shoulder slope planes with fill or cut slope planes.

25. Rounding - At the intersection of existing ground and cut slope.

26. Median Barrier - A longitudinal barrier used to prevent an errant vehicle from crossing the portion of a divided highway separating the traveled ways for traffic in opposite directions.

27. Guide Rail - A barrier whose primary function is to prevent penetration and safely redirect an errant vehicle away from a roadside or median hazard.

28. Top of Slope - The intersection of the cut slope and the original ground.

29. Toe of Slope - The intersection of the fill slope and the original ground.

30. Outer Separation - The portion of an arterial highway, between the traveled ways of a roadway, for through traffic and a frontage road.

31. Frontage Road - Also called marginal road or street. A local road, or street auxiliary, to and located on the side of an arterial highway for service to abutting property and adjacent areas and for control of access.

32. Roadside - The area adjoining the outer edge of the roadway (normally applies to freeways). The term "border" or "sidewalk area" is usually referred to street type facilities.

33. Outer Separation Island - The space in the outer edge of roadway shoulder and frontage roadway shoulder and frontage road or street which may be landscaped or paved depending on width.

34. Buffer Strip - The space in the border area provided to separate the sidewalk from the vehicular travel facilities.

35. Sidewalk - An exterior pathway with a prepared surface (concrete, bituminous, brick, stone, etc.) intended for pedestrian use.

NJDOT Roadway Design Manual 3-3

Definitions and Terminology

36. Curb or Curb and Gutter

37. Drainage Swale

38. Right-of-Way – A general term denoting land, property, or interest therein, usually in a strip acquired for or devoted to transportation purposes.

NJDOT Roadway Design Manual 3-4

Definitions and Terminology

NJDOT Roadway Design Manual 3-5

Definitions and Terminology

NJDOT Roadway Design Manual 3-6

Definitions and Terminology

3.3 Roadway Design Terms

Following are terms utilized by Roadway Designers.

3R Project – 3R stands for resurfacing, restoration, and rehabilitation.

Arterial Highway – This is a general term, denoting a highway used primarily for through traffic, usually a continuous route.

Auxiliary Lane - The portion of the roadway adjoining the traveled way intended for speed change, storage, weaving, climbing lane, and for other purposes supplementary to through traffic movement.

• Acceleration Lane - An auxiliary lane including tapered areas, primarily for the acceleration of vehicles entering the through traffic lanes.

• Collector-Distributor Lane - An auxiliary lane approximately 1/4 to 1/5 mile in length, designated to accommodate right turn access to and from the State highway at more than one location, and normally terminating at an intersection or an interchange ramp. It is not intended for through traffic, and is not physically separated from the through lanes. (Reference: N.J.A.C 16:47-1.1)

• Deceleration Lane - An auxiliary lane including tapered areas, primarily for the deceleration of vehicles leaving the through traffic lanes.

Buffer space - The space that separates traffic flow from the work activity and provides recovery space for an errant vehicle. Neither work activity nor storage of equipment, vehicles, or material should occur in this space. Buffer spaces may be positioned longitudinally and laterally, with respect to the direction of traffic flow.

Capacity - The maximum number of vehicles which has a reasonable expectation of passing over a given section of a lane or a roadway in one direction or in both directions for a two-lane or a three-lane highway during a given time period under prevailing roadway and traffic conditions.

Climbing Lane - An auxiliary lane introduced at the beginning of a sustained positive grade in the direction of traffic flow, to be used by slow moving vehicles such as trucks and buses.

Collector-Distributor Road, (C-D) - An auxiliary roadway separated laterally from, but generally parallel to, an expressway which serves to collect and distribute traffic from several access connections between selected points of ingress to and egress from the through traffic lanes. Control of access is exercised outside a C-D Road.

Control of Access - The condition where the rights of owners, occupants or other persons of land abutting a highway to access, light, air or view in connection with the highway are fully or partially controlled by a public agency.

• Full Control - The condition under which the authority to control access is exercised to give preference to through traffic to a degree, but in addition to interchange connections with selected public roads there may be some intersections at grade.

• Partial Control - The condition under which the authority to control access is exercised to give preference to through traffic to a degree that, in addition to access connections with selected public roads, there may be some crossings at grade and some private driveway connections.

NJDOT Roadway Design Manual 3-7

Definitions and Terminology

Corridor - A strip of land between two termini within which traffic, topography, environment, and other characteristics, are evaluated for transportation purposes.

Cul-de-Sac - A local street or road open at only one end with special provisions for turning around.

Dead-End Road - A local street or road open only at one end without special provisions for turning around.

Density - The number of vehicles per mile on the traveled way at a given instant.

Design Year - The design year for new construction and reconstruction is to be twenty years beyond the anticipated date of Plans, Specifications and Estimate

(PS&E), and ten years beyond the anticipated date of PS&E for resurfacing, restoration and rehabilitation projects. The estimated design year traffic volumes are used as a basis for design.

Direct Connection - A one-way turning roadway that does not deviate greatly from the intended direction of travel.

Directional Design Hourly Volume (DDHV) - An hourly volume determined for use in design, representing traffic expected to use one direction of travel on a highway

(Unless otherwise stated it is the directional hourly volume during the 30th highest hour).

Diverging - The dividing of a single stream of traffic into separate streams.

Divided Highway - A highway, street or road with opposing directions of travel separated by a median.

Expressway - A divided multi-lane arterial highway for through traffic, with full or partial control of access, and generally with grade separations at major intersections.

On rare occasions, expressways may also include two lane roadways.

Freeway - An expressway with full control of access and grade separations at all intersections.

Frontage Road or Frontage Street - A local street or road auxiliary to and located on the side of an arterial highway, for service to abutting property and adjacent areas, and for control of access.

Gore - The area immediately beyond the divergence of two roadways, bounded by the edges of those roadways.

Grade Separation - A crossing of two highways, or a highway and a railroad at different levels.

Highway Overpass - A grade separation, where the subject highway passes over an intersecting highway or railroad.

Highway Underpass - A grade separation, where the subject highway passes under an intersecting highway or railroad.

Inside Lane - On a multi-lane highway the extreme left hand traffic lane, in the direction of traffic flow, of those lanes available for traffic moving in one direction. This is also referred to as the left lane.

Interchange - A system of interconnecting roadways providing for the movement of traffic between intersection legs.

NJDOT Roadway Design Manual 3-8

Definitions and Terminology

Land Service Highway - An arterial or collector highway on which access to abutting property is permitted. On arterial highways and major collector roads, such access is usually regulated in order to protect the public safety and maintain the efficiency of the highway.

Left Turn Lane - A speed-change lane, within the median, to accommodate left turning vehicles.

Loads - Traffic data required for the establishment of geometric controls for highway design.

Local Authorities - County, municipal, and other local boards or bodies, having authority to enact laws relating to traffic.

Major Street or Major Road - An arterial highway with intersections at grade and direct access to abutting property, and on which geometric design and traffic control measures are used to expedite the safe movement of through traffic.

Separated Roadways - A highway with opposing directions of travel having independent alignment and gradient.

Shadow Vehicle - A traffic control truck with mounted crash cushions and arrow board showing arrow pattern positioned at an appropriate distance in advance of workers or a work vehicle during a multi-lane road moving operation. The shadow vehicle provides advance information to approaching drivers and shielding of the workers or work vehicle. The work vehicle may be a paint striping truck, cone retrieval truck or other operating vehicle.

Sight Distance - The length of roadway visible to the driver of a vehicle at a given point on the roadway when the view is unobstructed.

Slip Ramp - An angular connection between an expressway and a parallel frontage road.

Stopping Sight Distance - The distance required by a driver of a vehicle, traveling at a given speed, to bring a vehicle to a stop before reaching an object on the roadway after the object has become visible. The distances used in design are calculated on the basis of the driver's ability to see a 2 foot high object in the road ahead when driver’s eye level is 3.5 feet above the roadway surface.

TCP - Traffic Control Plan - A plan for maintaining traffic in or around a work zone.

Thirtieth Highest Hourly Volume (30HV) - The hourly volume in both directions of travel that is exceeded by 29 hourly volumes during a designated year.

Through Lane - The lane or lanes signed for through traffic continuing through an interchange area.

Through Street, Road or Highway - Any roadway, or portion thereof, on which vehicular traffic is given preferential right-of-way, and at the entrances to which vehicles from intersecting highways are required by law to either stop or yield.

Traffic Control Devices - Signs, Signals, markings, and devices placed or erected for the purpose of regulating, warning, or guiding traffic by authority of a public body or official having jurisdiction over the roadway.

Traffic Barrier - A device used to prevent a vehicle from striking a more severe obstacle or feature located on the roadside or in the median. They are also used to

NJDOT Roadway Design Manual 3-9

Definitions and Terminology prevent crossover median accidents. Traffic barriers include roadside barriers, median barriers, bridge…