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Nighttime Visibility of Traffic Signs: Appendix B - Retroreflectivity Advance Notice

APPENDIX B - RETROREFLECTIVITY ADVANCE NOTICE

[GH24] 

This appendix contains the text of the April 26, 1985 Federal Registeradvance notice of proposed amendments to the MUTCD regarding adding standards to the MUTCD for minimum in-service retroreflective performance of traffic control devices.

[Federal Register: April 26, 1985 (Volume 50, Number 81)]
[Proposed Rules]
[Page 16515-16517]

DEPARTMENT OF TRANSPORTATION

Federal Highway Administration
23 CFR Parts 625 and 655

[FHWA Docket No. 85-18]

National Standards for Traffic Control Devices, Manual on Uniform Traffic Control Devices; Standards for Performance of Retroreflective Traffic Control Devices; Request for Comments

AGENCY: Federal Highway Administration (FHWA), DOT.

ACTION: Advance notice of proposed amendments to the manual on uniform traffic control devices: request for comments.

SUMMARY: The FHWA is inviting comments on a petition from the Center for Auto Safety (CAS) to initiate rulemaking consideration on the issue of standards for retroreflective illumination of traffic control devices. If adopted, these standards could be incorporated into the Manual on Uniform Traffic Control Devices (MUTCD). The MUTCD is incorporated by reference in the design standards for Federal-aid highways found in Part 825 of Title 23, Code of Federal Regulations (CFR). It is also recognized in 23 CFR Part 655 as the national standard for traffic control devices on all public roads.

DATE: Comments must be received on or before February 15,1986.

ADDRESS: Submit written comments, preferably in triplicate, to FHWA Docket No. RS-18, Federal Highway Administration, Room 4205, HHC-10, 400 Seventh Street SW., Washington, D.C. 20590. All comments received will be available for examination at the above address between 7:45 a.m. and 4:15 p.m. e.t. Monday through Friday. Those desiring notification of receipt of comments must include a self-addressed, stamped postcard. The MUTCD is available for inspection and copying as prescribed in 49 CFR Part 7, Appendix D. It may be purchased for $30.00 from the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402, Stock No. 050-001-81001-8.

FOR FURTHER INFORMATION CONTACT: Mr. Philip 0. Russell, Office of Traffic Operations, (202) 426-0411, or Mr. Michael J. Laska, Office of the Chief Counsel, 426-0762, 400 Seventh Street SW., Washington, D.C. 20590. Office hours are from 7:45 a.m. to 4:15 p.m. e.t. Monday through Friday.

SUPPLEMENTARY INFORMATION: The FHWA both receives and initiates requests for amendments to the MUTCD. The MUTCD presents traffic control device (TCD) standards for all streets and highways open to public travel regardless of type or class or the governmental agency, having jurisdiction.

The MUTCD fulfills a statutory responsibility imposed on the Secretary of Transportation in sections 109(b), 109(d), and 402(a) of Title 23 of the U.S.C. and delegated to the Federal Highway Administrator in 49 CFR 1.48 (b), (c), and (n). Generally, 23 U.S.C. 109 authorizes the Secretary to develop, approve, and apply standards for the construction of highways in which Federal funds participate. Section 109(b) calls for standards for the Interstate System to be applied "uniformly throughout the States." Section 109(d) directs the secretary to approve only such standards for "the location, form, and character" of signs, signals, and markings on Federal-aid highways "as will promote the safe and efficient utilization of the highways." Section 402(a) authorizes the Secretary to promulgate uniform national standards relating to "highway design and maintenance (including lighting, markings, and surface treatment), traffic control, vehicle codes and laws, surveillance of traffic," etc., for use on all public roads.

This advance notice is being issued so that interested persons and/or organizations may have the opportunity to participate in the consideration of this request for amendments to the MUTCD. Based upon comments received in response to this advance notice and upon its own experience, the FHWA may prepare a notice of proposed amendments. Any final amendments which result from that action will be published in the Federal Register and incorporated by reference in the Code of Federal Regulation.

The basic requirements for highway signs and pavement markings are that they be legible and understood in time to permit a proper response. This means high visibility lettering or symbols of adequate size, and a short, accurate legend for driver comprehension at highway speed. Standard colors and shapes are specified so that special classes of traffic signs can be promptly recognized. Simplicity and uniformity in color, shape, position, and application are stressed throughout the MUTCD. The MUTCD presently provides that: (a) Regulatory and warning signs, unless excepted in the standards covering a particular sign or group of signs, shall be retroreflectorized or illuminated to show the same shape and color both by day and night, (b) pavement markings, which must be visible at night, shall be retroreflectorized unless ambient illumination assures adequate visibility, and (c) all pavement markings on Interstate highways shall be retroreflectorized.

The MUTCD contains no minimum initial or maintained retroreflective requirements for retroreflective signs, pavement markings, or traffic control devices. Minimum initial retroreflective requirements for new sheeting materials do exist. They are contained in General Services Administration's (GSA) Federal Specifications L-S-300C[2] and in "Standard Specifications for Construction of Roads and Bridges on Federal Highway Projects FP-79"[3] (FP- 79) U.S. DOT FHWA. The FP-79 is issued primarily for use in the construction of roads and bridges on Federal highway projects under the direct supervision of the FHWA. The State and local highway agencies have direct supervision of their respective systems including the Federal-aid highway systems and, therefore, are not bound by the FP-79. Many State and local highway agencies have elected to use either the GSA or the FP-79 specification for procurement of sign sheeting material. The FP-79 also contains minimum maintained retroreflective intensity specifications for sheeting materials in construction and maintenance zones. The FHWA is not aware of any State or highway agency that has adopted these standards.

The CAS petition acknowledges that the MUTCD sets forth standards for size, shape, and color as well as legend size and spacing for traffic control devices. However, the petition contends that the range of legally licensable drivers is not accommodated by the traffic control devices allowed in the MUTCD with respect to nighttime conspicuity dependent upon retroreflective illumination.

Copies of the CAS petition will be distributed to everyone currently appearing on the FHWA mailing list for MUTCD matters. Those wishing to be added to the mailing list or receive a copy of the petition should write to FHWA, Office of Traffic Operations, HTO-21, 400 Seventh Street SW., Washington, D.C. 20590.

Discussion of Problem

In the mid-1970's, approximately 55 percent of all vehicle deaths were reported to have occurred during the hours of darkness. By the early 1980's, the proportion of fatalities occurring at night bad increased steadily to about 60 percent. Given the facts that hours of darkness constitute only about 40 percent of a 24-hour day and only about 25 percent of all travel occurs during this same period, nighttime accidents are over-represented in accident statistics. The night fatality rate is more than three times that of the daytime rate. The rural driver has a significantly greater nighttime risk than the driver in urban areas when compared on the basis of relative exposure (per vehicle miles of travel). Approximately two-thirds of nighttime fatalities occur on unlighted roadways mainly in rural areas. The proportion of single vehicle fatalities occurring at night has increased from 62 to 68 percent between 1975 and 1982.

It is generally recognized that a single causal factor cannot be assigned to night accidents. A driver's night vision characteristics and a lack of adequate visual guidance information are significant factors in the greater accident and fatality rates at night. Fatigue, intoxication, inclement weather, higher speeds of travel on some roadways, and other factors all contribute to the hazards of night driving. For example, accident risks are considerably greater on wet pavements at night than on dry pavements. The problem is even more extreme for operation on wet roads with control of access. The risk of an accident under night, wet conditions on a freeway appears to be about 10 to 15 times greater than that during dry, daytime conditions.

All of the above mentioned factors are made worse by poor visibility. The great majority of information that the road user requires to effectively carry out driving in an efficient manner is obtained through the visual senses. The driver at night is presented with an extremely difficult task in a moving vehicle where the luminance level of the background scene and on the roadway itself often shifts very rapidly. The driver's light/dark adaptation must change quickly and continually as the light level is changed. The ability to detect and recognize objects falls off rapidly as the light level decreases to the level typical of night driving. Glare from oncoming vehicles and adjacent roadside developments present problems. Visual acuity, contrast sensitivity, distance judgment, speed of seeing, and color discrimination are all impaired by the relative darkness of the night driving environment. Therefore, anything done to enhance night visibility is likely to improve driver performance.

In addition to lighting, the primary techniques used to ameliorate the night visibility problem has been through the retroreflective treatment of signs, pavement markings, and delineators, and improved vehicular headlamp systems. Prior to 1980, there had been considerable research involving those techniques in simple, uniform backgrounds, aimed at improving legibility of signs and the detection distance at which objects are seen along the highway. For many roadway situations, particularly on low volume, rural roads, these studies showed vehicular headlamp illumination with limited pavement markings (i.e., center lines) and signing was sufficient to provide the driver with the needed guidance information. However, as the roadway environment becomes more complex, vehicular headlamps and deteriorating traffic control devices cannot provide the information needed for efficiently carrying out the driving task.

Laboratory studies suggest that only a modest level of illumination, far lower than daylight, is required to provide the necessary conditions for effective performance in almost any night driving environment. The difficulty of the driver's task and, therefore, the quality of visual information needed, is largely dependent upon the complexity of inputs presented to the visual senses. Visual complexity is determined by road geometry, maneuvering of other traffic, adjacent land uses, advertising signs, pedestrian activity, weather, traffic control devices, lighting, and maintenance of road features, and many other factors. Also important is the degree of driver impairment by such factors as alcohol and drugs, age, vision problems, and fatigue.

At the present time, the FHWA's research plans which address these subjects are based on the recognition that the most pressing research need is to develop an understanding of how operational complexity of the driving environment affects the various techniques being used to provide visual guidance information to the driver and how these techniques interact. This research builds on past knowledge to determine what techniques and equipment should be used in which specific situations and how often and by what methods traffic control devices should be refurbished or replaced.

Even upon the completion of the above research, the FHWA recognizes that a significant gap will exist between the new information (research results) and the successful adoption of acceptable minimum maintained retroreflection standards for traffic control devices. Therefore, the FHWA has decided to open a public docket to receive information concerning the practicality of developing retroreflection standards for traffic control devices as well as research and measuring methods/devices which would be needed to determine and to objectively measure retroreflection standards.

The FHWA has formulated the following questions and invites responses concerning the retroreflective performance of traffic control devices during periods of reduced visibility:

  1. Are standards needed for minimum maintained retroreflective performance requirements for traffic control devices (traffic signs, barricades, pavement markings, delineators, hazard markers, etc.) including those devices used in work zones?  Are maximum initial and maintained retroreflective performance requirements needed for any specific colors or applications?
  2. Should standards be based on retroreflectivity measurements or on minimum distances at which traffic control devices need to be visible and comprehensible to a motorist under a wide range of driving environments and conditions?
  3. Have any highway agencies established retroreflective performance standards for their traffic control devices?  If so, what are the basis of the performance standards?  How long have they been in use and are they adequate?  What problems have developed through their use?  How cost-effective are they?  Are these existing practices or procedures being used by highway agencies to determine when traffic control devices need to be replaced or refurbished?
  4. In establishing minimum maintained retroreflective requirements for traffic control devices, are there special needs to be considered such as the "design driver", driver information processing, aging motorists, glare sensitivity, vehicle characteristics (i.e., head lights, windshields, eye height), complex visual backgrounds, high information load, and weather?  Should a table be developed similar to Table II-1 "A Guide for Advance Warning Sign Placement Distance" as shown on page 2c-2a of the MUTCD?
  5. Should there be retroreflection uniformity within a single sign or of signs within a single display or should certain signs have higher retroreflection than other signs for example, Stop signs as compared to Do Not Litter signs)?  Are there available data or research results for classifying (in order of sign of importance) traffic sign retroreflection needs?
  6. Should traffic control devices retroreflective requirements be indicated in Specific Intensity per unit Area (SIA)[4], Coefficient of Luminous Intensity (CIL) per unit area[5], luminance[6], or other units?
  7. What instruments and procedures for measuring retroreflection of traffic control devices should be specified, are being used, or are available for use?  If instruments or procedures have been used, were they practical and satisfactory?
  8. What research studies are needed to develop reasonable performance standards?
  9. What research studies are needed to develop performance measuring instruments?
  10. Would comprehensive standards be cost-effective? Why or why not?

This advance notice of proposed rulemaking to the MUTCD is issued under the authority of 23 U.S.C. 109(d), 315, and 402(a), and the delegation of authority in 49 CFR 1.48(b).

It is anticipated that any proposed changes to the MUTCD resulting from the comments received would be included in a subsequent Notice of Proposed Rulemaking.

The FHWA had determined, at this time, that this document contains neither a major rule under Executive Order 12291 nor a significant proposal under the regulatory policies and procedures of the Department of Transportation. This determination will be reevaluated and a draft regulatory evaluation will be prepared, if necessary based upon the data received in response to this advance notice. Based upon the information available to the FHWA at this time, the action proposed in this advance notice will not have a significant economic impact on a substantial number of small entities.

List of Subjects in 23 CFR Parts 625 and 655

Design standards, Grant programs-transportation, Highways and Roads, Signs, Traffic regulations, Incorporation by reference.

(Catalog of Federal Domestic Assistance Program Number 20.205, Highway Research, Planning and Construction. The regulations implementing Executive Order 12372 regarding intergovernmental consultation on federal programs and activities apply to this program)

Issued on: April 22,1985.

R.A. Barnhart,
Federal Highway Administrator, Federal Highway Administration.

[FR Doc. 85-10178 Filed 4-25-85, 8:45 am]
BILLING CODE 4910-22-M

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