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Publication Number: FHWA-RD-01-051
Date: May 2001
Guidelines And Recommendations To Accommodate Older Drivers and Pedestrians
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The increasing number and percentage of older drivers using the Nation's highways in the decades ahead will pose many challenges to transportation engineers, who must ensure system safety while increasing operational efficiency. The 65 and older age group, which numbered 34.7 million in the United States in 2000, will grow to more than 36 million by 2005 and will exceed 50 million by 2020, accounting for roughly one-fifth of the population of driving age in this country. In effect, if design is controlled by even 85th percentile performance requirements, the "design driver" of the early 21st century will be an individual over the age of 65.
In 1998, FHWA published the Older Driver Highway Design Handbook, seeking to provide highway designers and engineers with a practical information source linking the declining functional capabilities of older road users to the need for design, operational, and traffic engineering enhancements keyed to specific roadway features. Early experiences with the recommendations, including extensive feedback from local- and State-level practitioners through workshops conducted for departments of transportation (DOT's) across the country in 1999 and 2000, indicated a need to revise and update this resource. The result is the Highway Design Handbook for Older Drivers and Pedestrians. Recent research has been incorporated, format and content changes have been made to improve its usefulness, guidance on how to implement its recommendations has been added, and the range of applications covered by the Handbook has been expanded.
This document contains the updated recommendations and information on how to apply the Handbook. These are excerpted from the full report (FHWA-RD-01-103), which also includes a detailed discussion of the rationale and supporting evidence for each recommendation. At the end of this document, supplemental technical notes not found in the full Handbook are provided to explain (1) how specific diminished capabilities lead to age-related driving problems; (2) license renewal requirements and distinctions for older drivers in each State in the U.S.; and (3) how and why to conduct visibility measurements to ensure that various pavement marking treatments covered in this Handbookserve the needs of older road users. These materials are included to support practitioners in exercising the engineering judgment often called upon to reach implementation decisions.
The recommendations in the Handbook do not constitute a new standard of required practice, but instead are intended to supplement existing standards and guidelines in the areas of highway geometry, operations, and traffic control devices to proactively respond to the changing demands on the Nation's roadway facilities. The recommendations provide guidance that is firmly grounded in an understanding of older drivers' and pedestrians' needs and capabilities, and can significantly enhance the safety and ease of use of the highway system for older persons, and for the driving population as a whole.
HOW TO USE THIS HANDBOOK
RELATING RECOMMENDATIONS TO STANDARD DESIGN GUIDES
Codes placed outside and to the left of each recommendation in this Handbook indicate its relationship to the design guides most frequently referenced by practitioners, as determined by the Handbook authors. An example is shown below.
Relationship codes 1 through 4, plus a fifth code (IEC), are defined as follows:
The standard design guides referenced by the relationship codes in the example above and throughout the Handbook are listed below. The most current published edition of each guide was consulted in the preparation of the Handbook, with the exceptions as noted.
INTERPRETING HANDBOOK GRAPHICS
The included figures and drawings are for illustrative purposes only, to clarify the meaning of a recommendation or to show what design was employed in a research study referenced in the Rationale and Supporting Evidence section. It is important to note that the fonts and arrow graphics used in this Handbook are not always consistent with the MUTCD-approved fonts and arrows. When employing recommendations included in this Handbook, only MUTCD-approved fonts and arrow graphics should be used.
A number of recommendations 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 recommendations of this nature, a look-up table on the next page provides the advance placement distance needed to achieve a desired preview time at a particular operating speed.
Advance Placement Distances Required to Achieve Desired Preview Times at Designated Operating Speeds
KNOWING WHEN TO IMPLEMENT THESE RECOMMENDATIONS
Implementation of the recommendations in this Handbook is expected to provide remedies for design deficiencies that disproportionately penalize older road users due to changes in functional ability experienced with normal aging. These may be most urgently needed where a crash problem with older 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 (1997) and ITE (1995), and it holds the key for applying the Handbook's recommendations as well.
The engineering enhancements described in this document should benefit all road users, not just older persons. However, if higher construction costs, the need for additional right-of-way, or other factors are present, special justification may be required for implementation of Handbookpractices. 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 separate Implementation Worksheet for meeting the requirements of each step is also provided. It is assumed that DOT's have in place processes that define when a crash pattern or a safety problem is evident; this Handbook does not address this level of analysis. Furthermore, it is recognized that States may already follow processes that make the approach described in this section unnecessary. FHWA has no desire to interfere with any procedures used by States that take the same information into account and accomplish the same ends as the three-step procedure below.
Step 1: Problem Identification [see worksheet on page 8]
During the planning stage for each project involving new construction or reconstruction of an existing facility, practitioners are asked to determine whether a problem with the safe use of the facility by older drivers and pedestrians 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 older drivers or pedestrians?"
Q2. "Has any aspect of design or operations at the project location been associated with complaints to local, municipal, or county-level officials from older road users or are you aware of a potential safety problem at this location, either through personal observation or agency documentation, applying your own 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, older 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:
Step 2: Identification of Candidate Handbook Applications [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 to identify every design element at the to-be-constructed facility for which a recommendation is included in the Handbook. These recommendations should be listed. Then, 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 recommendation(s). One possible example of how such worksheet entries could be made is shown below.
Step 3: Implementation Decision [see worksheet on page 10]
To begin Step 3, each Handbook recommendation identified as a candidate for imple-mentation in Step 2 should be properly referenced [e.g., I.E.4(4a)]. 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.
STEP 1: Problem Identification/Project Review Worksheet for Highway Design Handbook for Older Drivers and Pedestrians
Project Title/ID: _______________________________________________________________
Person Completing Worksheet: _________________________________ Date: ____________
Step 2: Identification of Candidate Handbook Applications
Identify design elements for which a recommendation exists in the Handbook and theapplicable recommendations. Then, (a) describe differences between the recommendation and standard practice, and (b) list benefits expected to result from implementing the Handbook.
Implementation Worksheet for Highway Design Handbook for Older Drivers and Pedestrians
Person Completing Worksheet:__________________________________________________ Date:______________
Step 3: Implementation Decision
List each recommendation identified as being a candidate for implementation. Document whether additional approval is needed, and whether increased costs or other special considerations may impact implementation. Based on these considerations, then decide whether or not implementation can be recommended. Check YES or NO, and add your initials to record your judgment. Add supplemental comments as deemed appropriate.
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Topics: research, safety, design, pedestrian & bicycle safety, visibility and retroreflectivity, older road user
Keywords: research, safety, highway design, highway operations, driver age, driver performance, human factors, vision, attention, perception, cognition, memory, physical ability, risk perception, hazard perception.
TRT Terms: Roads--United States--Design and construction, Roads--Visibility--United States, Roads--United States--Safety measures, Traffic signs and signals--United States, Older automobile drivers--United States--Safety measures, Pedestrians--United States--Safety measures, Pedestrian facilities design--United States, Aged drivers, Highway design, Human factors