Designing Sidewalks and Trails for Access

Part II of II: Best Practices Design Guide

Detectable Warnings

Detectable warnings are an Americans with Disabilities Act (ADA) requirement in the current Americans with Disabilities Act Accessibility Guidelines (ADAAG) for the use of detecting the boundary between the sidewalk and the street. The original requirement in ADAAG was suspended for a time to conduct further research. Research was conducted and the suspension of the requirement was lifted on July 26, 2001. At the time Designing Sidewalks and Trails for Access went to print, the suspension had not been lifted, so the text in Chapter 6 did not mention that detectable warnings are required.

Detectable warnings are now required when constructing and altering curb ramps. Truncated domes are the only detectable warnings allowed by ADAAG. The Access Board has detectable warning design information at www.access-board.gov/pubs.htm; scroll to Public Rights of Way, Guidance Material. The Building a True Community report has information on the new recommended detectable warning/truncated dome design based on the current research. FHWA concurs with this design. Chapter 6 has dome patterns that were acceptable at the time Designing Sidewalks and Trails for Access went to print, but are no longer considered acceptable. For information on the detectable warning requirement, see the US Department of Justice website, www.ada.gov/archive/detwarn.htm. FHWA policy on detectable warnings, released May 6, 2002, is posted at www.fhwa.dot.gov/environment/bicycle_pedestrian/resources/dwm.cfm.

Corrections

• Throughout: use 6.4 mm for the conversion of 1/4 inch. Background: ADAAG did not convert 1/4 inch consistently, it used 6.5 mm in figures, but it used 6 mm in text. The proposed new ADAAG uses 6.4 mm. (Pages 4-26, 4-27, 4-29, 14-7, 14-8, 15-15, 15-17, 17-4)
• Page 4-7, Table 4-2:
  • Each case of (60 m) on this page needs to be (60 in).
  • 1 d.u./acre equals 2.471 d.u./hectare; 4 d.u./acre equals 9.884 d.u./hectare.
  • Insert a footnote explaining d.u. is for dwelling unit.
• Page 4-26, bottom right column, last full sentence, should be: "Thus, the surface texture should be vibration free with a limit of 6.4 mm (1/4 inch) or less rise not more than every 760 mm (30 in)."
• Page 4-27, top of right column, should be: "surface texture should be vibration free with a limit of 6.4 mm (1/4 in) or less rise not more than every 760 mm (30 in)."
• Page 4-27, figure 4-34, replace the caption with: "Concrete with brick trim edging is easier for people with mobility impairments to negotiate.". In the diagram, delete the bricks across the sidewalk.
• Page 4-29: use 6.4 mm for the conversion of 1/4 inch.
• Page 4-32, revise Solution 4 to be: "Trim tree branches regularly to avoid having protruding branches lower than 2.03 m (80 in); or".
• Page 4-35, second column, near the middle: replace "9.30 m (30 ft)" with "760 mm (30 in)".
• Pages 6-6 through 6-9: This section is being rewritten to account for continuing work by the Access Board's Public Rights-of-Way Access Advisory Committee.
• Page 6-7, figure 6-5: eliminate diagonal alignment and triangular pattern. Correct the square pattern, parallel alignment (see below). Keep the dome profile view. NOTE: this change results from a change in recommended practice since the time this section was written.
  
  
  
  
• Page 6-7, column 2, full paragraph: replace the first three sentences with: "Detectable warnings must be aligned on a square grid in the predominant direction of travel to permit wheels to roll between the domes."
• Page 6-14 through 6-21, Section 6.5: Based on updated information on Accessible Pedestrian Signals, Section 6.5 will be replaced with new Sections 6.5 and 6.6, courtesy of Janet Barlow, Accessible Design for the Blind (www.accessforblind.org).
  • Page 6-14, column 1, line 9: replace "1999" with "1998".
  • Page 6-16, column 1, line 9: replace "LaRoache" with "Laroche".
  • Page 6-16, column 1, end of paragraph (before 6.5.3): add: "Note: See updated information at www.access-board.gov and http://www.apsguide.org."
• Page 6-20, first bullet, line 4: "least 915 mm x 1.22 m (36 in x 48 in), or 1.525 m x 1.525 m (60 in x 60 in)".
• Page 6-20, fourth bullet, line 2: "by 3 m (10 ft) is preferred.".
• Page 7-3, first column, lines 13 and 20: replace "12.3 mm" with "13 mm".
• Page 7-19, Table 7-2: switch the bottom middle picture and the top right picture (but keep the descriptions where they are).
• Page 7-21, Table 7-2, left column and right column: replace "Ramp slope" with "Parallel ramp slope".
• Page 7-26, Table 7-3, Insert "cross" before "slope" in the table caption. At the end, add "See also Figure 7-16."
• Page 7-29, figure 7-19: replace "24"" with "610 mm (24")".
• Page 7-31, first column: replace "2.75 m" with "230 mm", and replace "5.5 m" with "460 mm".
• Page 7-32, figure 7-25 caption: replace "0.75 mm" with "19 mm (0.75 in)".
• Page 7-38, switch the text for Figures 7-30 and 7-31, keep the drawings in place. Both drawings should show the ramp width as "1.22 m (48 in) min". For the current top drawing (current bottom text): replace "appex" with "apex"; delete the last sentence. For the current bottom drawing (current top text): In line 2, replace "curb ramp" with "landing".
• Page 8-7, Table 8-1, top: replace "2 (78 in)" with "2 m (78 in)".
• Page 8-7, Table 8-1, bottom left, English equivalent for 15 m: replace "(32.8 ft = 392 in)" with "(49.2 ft = 591 in)".
• Page 8-17, first column, 8^th line up from the bottom: replace "1.065 m" with "1.065 m/s".
• Page 8-17, second column, 5^th line: replace "3.5 ft/s" with "1.065 m/s (3.5 ft/s)".
• Page 8-18, Figure 8-14, Ramped median. In the drawing, for the passage width, add "1.525 m (60 in) preferred". The arrows for the median width should only extend for the level landing length. For the level landing length, add "1.525 m (60 in) preferred". In the caption, add "A minimum 1.525 m (60 in) x 1.525 m (60 in) level landing is preferred.".
• Page 8-18, Figure 8-15, Cut-through median. In the drawing, for the passage width, add "1.525 m (60 in) preferred". For the median width, add "1.83 m (72 in) preferred". In the caption, replace "and" with the following: "(1.525 m (60 in) preferred). A minimum 1.83 m (72 in) median width is preferred for pedestrian safety. It".
• Page 8-19, bottom of first column. Replace this sentence with: "If space permits, the cut-through passage width should be 1.525 m (60 in). The median width should be at least 1.83 m (72 in) for pedestrian safety.".
• Page 8-19, column 2, line 2: replace "asphalt" with "surface".
• Page 8-20, Figure 8-19, Cut through corner island. In the drawing, add "1.525 m (60 in) preferred". In the caption, after "wide", insert "(1.525 m (60 in) preferred)".
• Page 8-20, Figure 8-20, Ramped island. In the drawing, after "(48 in)", add "min; 1.525 m (60 in) preferred". In the caption, insert "landing" before the period.
• Page 8-21, text, column 2: replace lines 6 through 10 with: "(36 in) wide (1.525 m (60 in) preferred). If ramps are provided, the passage should be at least 915 mm (36 in) wide (1.525 m (60 in) preferred), with a center landing at least 1.22 m (48 in) (1.525 m (60 in) preferred). The ramp slope must not exceed 8.3 percent. Both".
• Pages 14-7, 14-8: use 6.4 mm for the conversion of 1/4 inch.
• Page 15-10, replace "3/4"" with "19 mm (3/4")"; replace "1-1/2"" with "38 mm (1-1/2")".
• Pages 15-15, 15-17: use 6.4 mm for the conversion of 1/4 inch.
• Page 16-9, 1^st bullet, line 3: replace "5 feet" with "1.525 m (5 feet)".
• Page 17-4: use 6.4 mm for the conversion of 1/4 inch.
• Page 17-9, figure 17-11: replace caption with: "A tactile wayfinding strip can indicate the presence of an interpretive display."

• This report needs a Technical Report Documentation page.
• Acknowledgments, page 2: Stuart MacDonald is "Macdonald", small "d".
• Acknowledgments, page 2, insert: Michael M. Moule
• Pages 6-6 through 6-9: this section needs a significant rewrite.
• Page 6-13, bottom right: correct line spacing error.
• Page 6-14 through 6-19: this section needs a significant rewrite.
• Page 7-19, first column, Gutter slope: for consistency, "5%" should be "5 percent".
• Page 7-19, middle column, top design recommendation: delete hyphen in "plant-ing".
• Page 7-29, figure 7-19: replace "24"" with "610 mm (24")". Enhance the upper drawing to show the wheelchair impact on the surface (similar to figure 7-20).
• Pages 7-33 through 7-38. The figures on page 7-38 belong with text on pages 7-33 and 7-35. Text and figures need to be closer together.
• Pages 8-19 through 8-21. For graphics purposes, some text on page 8-20 may need to come back to page 8-19, to allow shifting on page 8-20, to allow additional text on page 8-21.
• Page 15-8, bottom right column: insert comma after "wheelchairs".
• Page 15-12, Table 15-2, replace and realign text:
  

  Firm	8 mm (0.3 in) or less
  Moderately firm	8 mm to 13 mm (0.3 in to 0.5 in)
  Not firm	greater than 13 mm (0.5 in)

• Page 15-12, Table 15-3, replace and realign text:
  

  Stable	13 mm (0.5 in) or less
  Moderately stable	13 mm to 25 mm (0.5 in to 1.0 in)
  Not stable	greater than 25 mm (1.0 in)

• Page 15-15, 5^th bullet: correct spacing error.
• Page 18-2, bottom right column: replace "Portland, Oregon,(1996) and" with "Portland, Oregon (1996), and".
• Appendix C-2: Reference for Beneficial Designs needs the new address (see below).
• Appendix C-3: correct reference for National Center on Accessibility.
  

  National Center on Accessibility
  Indiana University
  2805 East 10th St, Suite 190
  Bloomington, IN 47408-2698
  Telephone: (812) 856-4422 (Voice)
  TTY: (812) 856-4421
  Fax: (812) 856-4480
  E-mail: nca@indiana.edu
  Website: www.ncaonline.org

• Appendix H: Pages H-3, H-4, H-5, H-11, References for Beneficial Designs. Use:
  

  Beneficial Designs, Inc.
  PO Box 69
  Minden, NV 89423-0069
  Telephone (775) 783-8822
  Fax (775) 783-8823
  Email: paxpress@beneficialdesigns.com
  Web: www.beneficialdesigns.com

• Appendix H-16, first column, near bottom, delete line "Washington DC: Author".
• Appendix H-19, correct reference using Appendix C-3 address (above).
• Appendix H-21 and H-22, correct references to:
  

  Institute of Transportation Engineers
  1099 14th St NW, Suite 300 West
  Washington, DC 20005-3438
  Telephone (202) 289-0222
  Fax (202) 289-7722
  Email: ite_staff@ite.org
  Website: www.ite.org

• Appendix H-25, first column, delete "Bill Feldman", and change email to: "sheree.davis@dot.state.nj.us".
• Appendix H-32, change entry for American Trails to:
  

  American Trails
  PO Box 491797
  Redding CA 96049-1797
  Telephone: (530) 547-2060
  Fax: (530) 547-2035
  Email: info@americantrails.org
  Website: <http://www.americantrails.org>