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                        Handbook for Designing Roadways for the Aging Population


            
            In This Section
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                Chapter 1. How to Use this Handbook
Organization of the Handbook

The *Handbook* consists of two parts. Part I includes recommended treatments for 33 traffic control or geometric design elements divided among five categories. The five categories of treatment are as follows:

Intersections,
	Interchanges,
	Roadway Segments,
	Construction/Work Zones, and
	Highway-Rail Grade Crossings.These treatments are recommended because they have been shown through research to be a benefit to the aging road user. In addition, 18 "Promising Practice" treatments are included. These are treatments being utilized by transportation agencies that should benefit aging road users as determined by a subjective assessment by staff participating on the development of this *Handbook*. Current trends indicate these practices have a positive impact on aging road user safety. These promising treatments are placed at the end of each category to which they apply.

Part II includes the rationale and supporting evidence for each of the treatments. This part of the *Handbook* is also divided into these same five categories.

The treatments for each design element are presented as shown in Figure 1 and consist of the following components:

Category — At the top of each page is a header showing the category of treatment (i.e., Intersections, Interchanges, Roadway Segments, Construction Work Zones and Highway-Rail Grade Crossings).
	Design Element — Each element has a unique number for quick reference to the Table of Contents.
	Treatments — Each treatment within a design element is clearly identified by a unique letter, followed by a recommendation on how that treatment should be used.
	Figure(s) — Many of the concepts described in the treatments are illustrated in figures—as photographs, figures extracted from the MUTCD or other publications, or as drawings. **The drawings are for illustrative purposes only; they are not to scale and should not be used for design purposes. It is important to note that the lettering styles, arrows and symbols used in this Handbook are not always consistent with those prescribed in the MUTCD.** When employing treatments included in this *Handbook*, only MUTCD-approved lettering styles, arrows and symbols should be used. Additionally, any highway agency wishing to implement a treatment that has not been included in the most recent edition of the MUTCD, and thus denoted by a relationship code of "5"(see Table 1), must request experimentation approval from the FHWA.
	References and Relationship Codes — References placed below each treatment indicate its relationship (by a numeric relationship code) to the design guides most frequently referenced by practitioners, as determined by the *Handbook* authors. A legend is provided at the bottom of each treatment page to remind users (in an abbreviated format) of the meaning of the numerical values. The complete definitions for these relationship codes are provided in Table 1.Figure 1. An image of the Handbook page describing treatments for Street Name Signs, with callout boxes to describe details of specific parts of the page (i.e., category and chapter number, design element number, treatment, and references and relationship codes).

Figure 1. Elements included for each *Handbook* treatment

Table 1. Definitions for the relationship codes between the recommendations and existing design guides or other manuals.
	Code
			Definition1
			*Handbook* treatment selects the most conservative design value among present options in the standard manual/guideline. (Example: Using a larger sign size identified as an "option"in the *MUTCD*).2
			*Handbook* treatment indicates the preferred design value where a discrepancy exists among two or more manuals/guidelines. (Example: Limit skew to 75° as per TEH instead of 60° as per *Green Book*).3
			*Handbook* treatment extends a current practice to a new application or operation. (Example: Use of fluorescent sheeting on wrong-way control signing, for increased conspicuity).4
			*Handbook* treatment advances a specific design value or concept where only general guidance now exists, or provides more detailed or more stringent design criteria than are currently specified. (Example: It is recommended that an advance street-name plaque be used wherever an advance intersection warning sign is installed. The use of this supplemental plaque is an option per engineering judgment in the 2009 *MUTCD*.)5
			*Handbook* treatment is permissible at this time only in accordance with the provisions of *MUTCD* Section 1A.10, *Interpretations, Experimentations, Changes and Interim Approvals*. These treatments represent advances in technology which research indicates will result in improved safety and efficiency of operations. (Example: It is recommended that the Roundabout Circulation Plaque (R6-5P) be placed immediately below the R1-2 Yield sign on both sides of the road at each entrance to a roundabout.)The design guides, manuals, and other resources referenced by the relationship codes in the treatments and throughout the *Handbook* are shown in Table 2. The most current published edition of each guide was consulted in the preparation of the *Handbook*, with the exceptions as noted. The latest version of the MUTCD can be accessed at http://mutcd.fhwa.dot.gov.

In addition to the design guides shown in Table 2, there are a number of other resources and supporting tools available to assist in improving the roadway environment for aging (and all) road users. Some key resources include:

Interactive Highway Safety Design Model (IHSDM): A suite of software analysis tools for evaluating safety and operational effects of geometric design decisions on two-lane rural highways (https://www.fhwa.dot.gov/research/tfhrc/projects/safety/comprehensive/ihsdm/).
	Highway Safety Manual (HSM), 1st Edition, Volumes 1, 2 and 3, 2010: This resource provides safety knowledge and tools to facilitate improved decision-making based on safety performance (http://www.highwaysafetymanual.org).
	SafetyAnalyst: Analytical tools for use in the decision-making process to identify and manage a system-wide program of site-specific improvements to enhance highway safety by cost-effective means (http://www.safetyanalyst.org/).
	Human Factors Guidelines for Road Systems, NCHRP Report 600: This report is designed to help non-experts in human factors to consider more effectively the roadway user's capabilities and limitations in the design and operation of highway facilities (http://www.trb.org/Main/Blurbs/167909.aspx).
	NCHRP Report 500: Guidance for Implementation of the AASHTO Strategic Highway Safety Plan: A series of guides to assist transportation agencies in reducing specific types of crashes in targeted emphasis areas outlined in the AASHTO Strategic Highway Safety Plan (http://www.trb.org/main/blurbs/152868.aspx).
	Pedestrian Road Safety Audit Guidelines and Prompt Lists: A guide for conducting formal safety examinations of future roadway projects or in-service facilities with a focus on identifying and addressing pedestrian safety concerns (http://www.walkinginfo.org/data/library/details.cfm?id=3955). Similarly, a guide is available for conducting more general road safety audits (http://safety.fhwa.dot.gov/rsa/).
	AASHTO Guide for the Planning, Design, and Operation of Pedestrian Facilities: Guidelines are included for the construction and design of sidewalks, street crossings, and many aspects of pedestrian trails. The document is available for purchase at https://bookstore.transportation.org/.
	PEDSAFE: Pedestrian Safety Guide and Countermeasure Selection System: This interactive system is intended to help practitioners choose the most appropriate engineering, education, and enforcement countermeasures to address pedestrian safety and mobility issues (www.walkinginfo.org/pedsafe).For additional resources, visit the FHWA Office of Safety web site at http://www.fhwa.dot.gov/safety.

Table 2. Abbreviations used for the references cited in the recommendation chapters.
	Abbreviation Key
			Reference Citation*Green Book*
			*A Policy on Geometric Design of Highways and Streets (Green Book)*. American Association of State Highway and Transportation Officials, 2011.HCM
			*Highway Capacity Manual*. Transportation Research Board, 2010.MUTCD
			*Manual on Uniform Traffic Control Devices for Streets and Highways*. (2009 Edition). Federal Highway Administration, 2009.NCHRP 279
			*Intersection Channelization Design Guide*, (NCHRP Report 279). National Cooperative Highway Research Program, 1985.NCHRP 500-9
			*Guidance for Implementation of the AASHTO Strategic Highway Safety Plan, Volume 9: A Guide for Reducing Collisions Involving Older Drivers*, (NCHRP Report 500, Volume 9). National Cooperative Highway Research Program, 2004.NCHRP 672
			NCHRP Report 672, *Roundabouts: An Informational Guide*(Second edition).NCHRP 674
			*Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities*, (NCHRP Report 674). National Cooperative Highway Research Program, 2010.RLH
			*FHWA Lighting Handbook*, Federal Highway Administration, 2012.RRX
			*Railroad-Highway Grade Crossing Handbook*, Revised 2nd Edition. Federal Highway Administration, 2007.TEH
			*Traffic Engineering Handbook*, 5th Edition. Institute of Transportation Engineers, 2009.Time-Speed-Distance Table

A number of treatments presented in the *Handbook* identify the placement of a device or treatment in terms of the preview time that should be provided to the driver for its application. These values are typically expressed in seconds, such that the recommended placement of the device or treatment depends upon the speed at which traffic is moving. To facilitate application of *Handbook* treatments of this nature, Table 3 provides the advance placement distance needed to achieve a desired preview time at a particular operating speed.

Table 3. Advance placement distances required to achieve desired preview times at designated operating speeds.
	Preview Time (seconds)
			Operating Speed (mph)30
			35
			40
			45
			50
			55
			60
			65
			70
			75
			802.5
			110
			128
			147
			165
			183
			202
			220
			238
			257
			275
			2933.0
			132
			154
			176
			198
			220
			242
			264
			286
			308
			330
			3523.5
			154
			180
			205
			231
			257
			282
			308
			334
			359
			385
			4114.0
			176
			205
			235
			264
			293
			323
			352
			381
			411
			440
			4694.5
			198
			231
			264
			297
			330
			363
			396
			429
			462
			495
			5285.0
			220
			257
			293
			330
			367
			403
			440
			477
			513
			550
			5875.5
			242
			282
			323
			363
			403
			444
			484
			524
			565
			605
			6456.0
			264
			308
			352
			396
			440
			484
			528
			572
			616
			660
			7046.5
			286
			334
			381
			429
			477
			524
			572
			620
			667
			715
			7637.0
			308
			359
			411
			462
			513
			565
			616
			667
			719
			770
			8227.5
			330
			385
			440
			495
			550
			605
			660
			715
			770
			825
			8808.0
			352
			411
			469
			528
			587
			645
			704
			763
			822
			880
			939Knowing When to Implement these Recommendations

Implementation of the treatments in this Handbook provide benefits for design challenges that disproportionately affect aging road users due to changes in functional ability experienced with normal aging. These may be most urgently needed where a crash problem with aging drivers or pedestrians has already been demonstrated; however, the greater benefit arguably lies in designing safer new roads and identifying and modifying problems with existing roads before statistics reveal a crash problem. Not only does this practice minimize the risk and severity of crashes, it minimizes the need for remedial works after construction, thus reducing the whole-life cost of projects. This is the central premise of the road safety audit process supported by FHWA and it holds the key for applying the *Handbook* treatments as well.

The engineering enhancements described in this document should benefit all road users. Special justification may be required for implementation of *Handbook* practices. This section was developed to support engineering judgment in this regard. It suggests a three-step procedure using checklist responses plus brief written comments, as explained below. A set of optional worksheets for documenting each step is also provided.

Step 1: Problem Identification [*see Project Review Worksheet on page 7*]

During the planning stage for each project, practitioners are asked to determine whether a problem with the safe use of the facility by aging road users currently exists or may reasonably be expected based on current and projected use patterns. Using the first worksheet that follows this discussion, problem identification can be accomplished by checking YES or NO to the following four questions:

Q1. "Is there a demonstrated crash problem with aging road users?"
	Q2. "Has any aspect of design or operations at the project location been associated with complaints to local, municipal, or county-level officials from aging road users or are you aware of a potential safety concern for aging road users at this location, either through observation, agency documentation, or engineering judgment?"
	Q3. "Is this project located on a direct link to a travel origin or destination for which, in the judgment of local planning/zoning authorities or other local officials, aging persons constitute a significant proportion of current users?"
	Q4. "Is the project located in a census tract or zip code designation that has experienced an increase in the proportion of (non-institutionalized) residents age 65 and older, for the most recent period in which the population was sampled?"To answer these questions, practitioners will need to obtain reliable crash data from the appropriate division or bureau of their departments of transportation. At least the three most recent years for which data are available should be examined, and the data should be sorted by age, at a minimum. Sources of information outside of the State DOT also may be required to answer the problem identification questions. Potential sources include, but are not limited to:

Local government officials/Board of Supervisors/city council representatives.
	Local and State police.
	The (State) Department of Aging and/or county Area Agency on Aging.
	The (State) Department of Health and Human Services and Department of Public Welfare.
	The regional planning commission.Step 2: Identification of Design Elements and Treatments [*see worksheet on page 9*]

For each project where a practitioner has answered YES to one or more of the problem identification questions in Step 1, the next step is consider all categories (i.e., intersection, interchanges, roadway segments, construction/work zones, and highway-rail grade crossings) on the facility. Then, for each category, consider each design element and treatment that could be applied. For each one, the engineer should indicate whether the recommended practice differs from standard State or local practices, and if yes, what additional benefits are expected to result from implementing the applicable *Handbook* treatment(s). One possible example of how such worksheet entries could be made is shown in Table 4.

Project Review Worksheet

Project Title/ID: _______________________________________________________________

Person Completing Worksheet: __________________________________________________ Date: ________________________

Q1.
			"Is there a demonstrated crash problem with aging road users?"
			YES checkbox
			NO checkboxSource(s)
			Date of ContactQ2.
			"Has any aspect of design or operations at the project location been associated with complaints to local, municipal, or county-level officials from aging road users or are you aware of a potential safety concern for aging road users at this location, either through observation, agency documentation, or engineering judgment?"
			YES checkbox
			NO checkboxSource(s)
			Date of ContactQ3.
			"Is this project located on a direct link to a travel origin or destination for which, in the judgment of local planning/zoning authorities or other local officials, aging persons constitute a significant proportion of current users?"
			YES checkbox
			NO checkboxSource(s)
			Date of ContactQ4.
			"Is the project located in a census tract or zip code designation that has experienced an increase in the proportion of (non-institutionalized) residents age 65 and older, for the most recent period in which the population was sampled?"
			YES checkbox
			NO checkboxSource(s)
			Date of ContactREPRODUCE THIS PAGE AS NEEDED

Table 4. Example of Completed Design Elements and Treatments Worksheet.
	Category
			Design Element
			Applicable *Handbook* Treatment
			Differs From Existing State or Local Practice?
			If YES...NO
			YES
			Explain Difference
			Identify Expected BenefitsIntersections
			1. Intersecting Angle (Skew)
			(1C) Skewed Signalized Intersection
			
			✓
			According to MUTCD warrants, there is "adequat" sight distance and fewer than 3 RTOR crashes annually on approach.
			Should reduce the difficulty for aging drivers to check for approaching traffic, and also reduce aggressive behavior of following drivers who don't accept an aging driver's decision not to turn on red.Intersections
			10. Street-Name Signs
			(10A) Letter Heights and Sign Border
			✓Intersections
			16. Roundabouts
			(16C) Splitter Islands
			✓Intersections
			24. Flashing Yellow Arrow
			(Promising Practice for permissive left turns)
			
			✓
			Current practice uses a green ball for permissive left turns.
			Should improve the ability of aging drivers to correctly recognize when permissive left turns are allowed.Construction/ Work Zones
			43. Signing and Advance Warning
			(43C) Sign Sheeting
			✓Step 3: Implementation Decision [*see worksheet on page 10*]

To begin Step 3, each *Handbook* treatment identified as a candidate for implementation in Step 2 should be properly referenced [e.g., 5D(1)]. Next, any factors relating to increased costs (for an enhanced treatment), added approvals that may be needed, or any other special considerations that impact implementation may be noted in separate columns on the worksheet. The final step is then to proceed to an implementation decision. This is recorded as a judgment by the engineer as to whether implementation of the candidate countermeasure is recommended. The engineer's judgment is indicated by a check in the space next to YES or NO in the last column on the worksheet, accompanied by his/her initials for verification. Additional comments should be entered as deemed appropriate.

Identification of Design Elements and Treatments Worksheet

Project Title/ID: _______________________________________________________________

Person Completing Worksheet: __________________________________________________ Date: ________________________

Identify design elements for which a treatment exists in the *Handbook* and the applicable treatments. Then, (a) describe differences between the treatment and standard practice, and (b) list benefits expected to result from implementing the *Handbook*.

Category
			Design Element
			Applicable *Handbook* Treatment
			Differs From Existing State or Local Practice?
			If YES...NO
			YES
			Explain Difference
			Identify Expected BenefitsREPRODUCE THIS PAGE AS NEEDED

Implementation Worksheet

Project Title/ID: _______________________________________________________________

Person Completing Worksheet: __________________________________________________ Date: ________________________

List each treatment identified as a candidate for implementation. Document whether additional approval is needed (i.e., Environmental, Regulatory, etc.), and whether increased costs or other special considerations may affect implementation. Based on these considerations, decide whether implementation can be recommended, add your initials, and add supplemental comments as appropriate.

Treatment
			Implementation Considerations
			Implementation Recommended?Added Costs?
			Added Approvals?
			OtherInitials________
			NO________
			YES________
			Comments:Initials________
			NO________
			YES________
			Comments:Initials________
			NO________
			YES________
			Comments:REPRODUCE THIS PAGE AS NEEDED
      
  Book traversal links for Chapter 1. How to Use this Handbook
      ‹ Abbreviations and Acronyms
                    Up
                    Part I. Treatments ›
                
                Book:Handbook for Designing Roadways for the Aging Population
              Preface
                Acknowledgements
                Abbreviations and Acronyms
                Chapter 1. How to Use this Handbook
                Part I. Treatments
                Chapter 2. Intersections
                Chapter 3. Interchanges
                Chapter 4. Roadway Segments
                Chapter 5. Construction/Work Zones
                Chapter 6. Highway-Rail Grade Crossing
                Part II. Rationale and Supporting Evidence
                Chapter 7. Intersections
                Chapter 8. Interchanges
                Chapter 9. Roadway Segments
                Chapter 10. Construction/Work Zones
                Chapter 11. Highway-Rail Grade Crossings
                APPENDIX A
                APPENDIX B
                APPENDIX C
                APPENDIX D U.S. DEPARTMENT OF TRANSPORTATION

**Federal Highway Administration**

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WASHINGTON, DC 20590

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