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Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations

This report is an archived publication and may contain dated technical, contact, and link information
Publication Number: FHWA-HRT-04-103
Date: October 2004

Characteristics of Emerging Road and Trail Users and Their Safety

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The effectiveness and value of this research is largely dependent on its use by practitioners and policymakers making decisions about roadway and shared use path design and safety programs, respectively. Thus the goal of the marketing plan is to outline how to disseminate the information to transportation professionals, trail designers/coordinators, landscape architects, engineers, public works officials, and other professionals and policymakers. Data from the summary charts and formulas can be incorporated into the existing formats of national guidelines such as the AASHTO Green Book, ADAAG, and the AASHTO Guide for the Development of Bicycle Facilities, and other appropriate documents.

Since shared use paths, in particular, are designed by professionals from a variety of backgrounds, the marketing plan outlines methods of reaching various types of professionals through publications, journal articles, conference presentations, and other means. With that primary goal established, the first and foremost objective is to get the word out.

Getting the word out on this study is important for several reasons:

  • First, the data contain important information with myriad uses. The study provides immediately usable data by engineers who employ the various calculations to establish intersection sight triangles, vertical and horizontal curves, and numerous other features of the transportation environment.

  • Second, as stated in the previous section, this FHWA study has revealed that although currently the bicycle is used as the design vehicle for shared use path design, in many cases, the bicycle is probably not the appropriate design vehicle for many elements of a shared use path facility, nor is it for signalized intersections of streets. The design of signalized intersections and midblock (pedestrian and/or trail) crossings (both signalized and unsignalized) will be affected by the new information and findings of this study.

  • Consequently, and third, discussions of the results of this study with transportation professionals at the various recommended interactive marketing venues for this study (presentations, NHI courses, etc.) will create even more insight into what is the best way for planners, designers, engineers, and operators of shared use paths, streets, bicycle and sidewalk facilities, and midblock crossings to more safely accommodate the myriad existing and emerging users. Either a consensus on the design user or a methodology for that determination needs to be established quickly.

  • Finally, these important discussions and deliberations with practitioners will help clarify what is the most prudent way to modify the existing design guidebooks and/or create a separate one for shared use paths and related transportation facilities to help speed the process of ensuring that all designs will be safe and efficient for all users of transportation facilities.

Accordingly, this section of the Final Report outlines both the recommended marketing plan (table 24) as well as the needed elements for either revisions to NHI's bicycle and pedestrian facility design courses and the existing AASHTO design guidelines, or the creation of a totally new NHI course and a new AASHTO design guideline (for shared use paths).

Table 24. Marketing plan.

Aug 2003 TRB Paper Technical paper Yes Yes
ASAP NHI Course New NHI course development (or modification to both the bicycle and pedestrian facility design courses) (also incorporate results from the FHWA study "Operation of Shared Use Paths") Yes / No In progress
Jan 2004 TRB Committee on Pedestrians A3B04 Comm. Mtg. Slide presentation Yes Yes
Jan 2004 TRB Committee on Bicycling A3B07 Comm. Mtg. Slide presentation Yes Yes
Jan 2004 TRB paper Poster session Yes Yes
Jan 2004 National Committee on Uniform Traffic Control Devices Manual on Uniform Traffic Control Devices Presentation to subcommittee No Yes
Mar 2004 Midwest Regional Bike/Ped Conference Slide presentation Yes Yes
Jun 2004 AASHTO Subcommittee on Design Slide presentation No No
Aug 2004 Institute for Traffic Engineers (ITE) Annual Meeting Slide presentation No No
Sept 2004 Nationwide State B/P Coordinators' Meeting Slide presentation No No
Sept 2004 Conference ProWalk / ProBike Slide presentation No No
Sept 2004 Association of Pedestrian and Bicycle Professionals (APBP) Seminar Series Short course No No

The slide presentation, a Microsoft® PowerPoint® file, outlines how the study developed; how the data collection plan was designed; how well the events ran; the variety of users, abilities, and ages in attendance; and the results and implications. A paper describing the study and findings was submitted to TRB and was presented at the 2004 Annual Meeting. Finally, outlined below are the recommended elements for either revisions to NHI's bicycle and pedestrian facility design courses and the existing AASHTO design guidelines, or the creation of a totally new NHI course and an AASHTO design guideline (for shared use paths). Examples of other venues through which this study can be publicized include:

  • Publications-ITE Journal, ITE Ped/Bike Council Newsletter

  • Web sites-www.walkinginfo.org, http://safety.fhwa.dot.gov/ped_bike/pedforum/index.cfm (FHWA Office of Safety's Pedestrian Forum Newsletter), http://www.fhwa.dot.gov/hep/index.htm (FHWA Office of Planning, Environment, and Realty).

  • E-mails to listservs-State Ped/Bike Coordinators, TRB Pedestrian Research Committee, ITE Ped/Bike Council, Pedestrian Rights of Way and Accessibility Committee, APBP, FHWA Field Safety Specialists, etc.

Design of Shared Use Paths, Street Intersections, and Midblock Crossings

This federally sponsored research reveals that in many cases, neither the bicycle nor the pedestrian is the design "vehicle" or user for shared use paths, their intersections with roadways, or for a host of other features throughout the transportation system of the United States. This is an important discovery, confirming what some professionals have suspected: that a number of our design guidelines need to be changed or expanded, and/or new ones added. This is an urgently needed action. Hundreds, if not thousands, of transportation facilities and signals are being designed and built today that do not, or will not, in the very near future, safely accommodate a growing number of nonmotorized users. While the above outlined presentations may help bring about a general awareness within the professional community of bicycle and pedestrian mode planners, they represent a small portion of the design professionals preparing designs and construction documents of signalized roadway and street intersections, midblock pedestrian signals, shared use paths, roads and streets, etc. These tens of thousands of design professionals need to be aware of the possible implications of this study on transportation system designs.

Figure 53: Photo. Many users of various ages and abilities participated in each "Ride for Science." Many participants have just registered and are now lined up across the parking lot, waiting to start. Several appear to be youth.
Figure 53. Many users of various ages and abilities participated in each "Ride for Science."

Furthermore, they need training on the proper design to safely accommodate the growing array of users of transportation facilities (figures 53 and 54), and the operational characteristics of persons using the expanding array of assistive devices.

Figure 54: Photo. Two "Ride for Science" participants. Two older participants on bicycles are standing in the parking lot.
Figure 54. two "Ride for Science" participants.

Accordingly, either revisions are needed to NHI's bicycle and pedestrian facility design courses, the existing AASHTO design guidelines (A Policy on Geometric Design of Highways and Streets, Guide to the Development of Bicycle Facilities and the upcoming Pedestrian Facilities Design Guide) and FHWA's Manual on Uniform Traffic Control Devices (MUTCD), and/or the creation of a totally new NHI course and a new AASHTO design guideline (for shared use paths) should be created. The information could also be put into the revised Ped/Bike University Course. Regardless of the approach taken, certain recommended minimum elements are needed for courses/design guidelines to ensure the safe design and operation of transportation facilities serving nonmotorized users. The major sections that need to be included or referenced are:

  1. Design Controls and Criteria.
  2. Elements of Design.
  3. Cross-sectional Elements.
  4. At-grade Intersection Design.
  5. Design of Grade-separated Crossings.
  6. Sidewalks and "Sidepath" Design Guidance.

These sections are further detailed below.

Section 1-Design Controls and Criteria

  1. Function and Purpose of Shared Use Paths, Street Intersections, and Midblock Crossings
    1. History of the Facility Types
    2. Expectations of the Users
  2. Design Users and Operational Characteristics
    1. Population of Current and Emerging Users
    2. Bicyclists
    3. Pedestrians
    4. Inline Skaters
    5. Recumbents
    6. Hand Cycles
    7. Wheelchair Users
    8. Canes, Walkers, and Related Ambulatory Devices
    9. The Segway
    10. Etc.
  3. Facility Operation and Level of Service Concepts
    1. Homogenous User Operation
    2. Bicycle and Pedestrian Users
    3. Mixed Flow
    4. Street Intersections
    5. Midblock Crossings
  4. ADA Geometric Criteria
  5. Speed
    1. Operating Speed
    2. Running Speed
    3. Design Speed

2. Section 2-Elements of Design

  1. Sight Distance
    1. Stopping Sight Distance
      1. Reaction Time
      2. Braking Distance
      3. Design Values
    2. Criteria for Measuring Sight Distance
      1. User Eye Heights
      2. Object Height
  2. Horizontal Alignment
    1. General Considerations
      1. Superelevation
      2. Friction Factors
    2. Design Considerations
    3. Sight Distance on Horizontal Curves
      1. Stopping Sight Distance
      2. Passing Sight Distance
  3. Vertical Alignment
    1. Grades
    2. Vertical Curves
      1. General Considerations
        1. Population of Users
        2. Critical Design User
    3. Crest Vertical Curves
    4. Sag Vertical Curves
    5. Sight Distance at Undercrossings (Grade Separated Intersections)

3. Section 3-Cross Section Elements

  1. Pavement
  2. Width
  3. Shoulders and Sideslopes
    1. Width and Slope of Shoulders
    2. Horizontal Clearance to Obstructions
    3. Sideslopes
  4. (Traffic) Barriers and Railings
  5. Cross Sections through Grade Separated Intersections

4. Section 4-At-Grade Intersections

  1. General Design Considerations and Objectives
  2. Operational Capabilities of Users
    1. Acceleration
    2. Gap Acceptance
    3. Future Trends in Capabilities
  3. Types and Examples of Intersections
    1. Signalized Street Intersections
    2. Midblock Crossings
  4. Assignment of Priority
    1. Yield
    2. Stop
    3. Signalized Control
  5. Intersection Sight Distance
    1. Path / Path intersections
      1. Sight Triangles
        1. Approach Sight Triangles
        2. Departure Sight Triangles
      2. Intersection Control
    2. Roadway / Path (Midblock) Intersections
      1. Sight Triangles
        1. Approach Sight Triangles
        2. Departure Sight Triangles
      2. Median Refuges
      3. Alternative Routing of Shared Use Path
  6. Ramps and Vertical Design Considerations
  7. Treatments through Interchange Areas
  8. Crossing Safety Intervention Measures

5. Section 5-Grade Separated Intersections

  1. Warrant Guidelines for Grade Separation
  2. Overpass versus Underpass Structures
  3. Lateral and Vertical Clearances
  4. Approaches (e.g., Ramps and Elevators)

6. Section 6-Sidewalks and Sidepaths

  1. Introduction and History
  2. Crash Statistics
  3. The Conflicts and Confusion
  4. The Limited Applications and Design Guidelines

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