Memorandum - NHTSA

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v-11 During the development of an NPRM for vehicles with wheelchair lifts (previously called FMVSS No. 401), the agency proposed a procedure for measuring platform resistance in whkh a loaded power wheelchair would be placed on a wet, 30 degree inclined lift surface until sliding occurred. This was believed to occur at about a 0.60 coefficient of friction (COF). Unfortunately, testing at VRTC (Docket No. NHTSA-98-45 11) revealed that this was not an effective method because, in many cases, the wheelchair tipped over before sliding could occiir. Subsequently, VRTC staff conducted a literature search to determine other test procedures, wl iich might be useful in determining slip resistance and selected ANSVRESNA WC13 - 1991 Determination of Coefficient of Friction of Test Surfaces for further investigation. NHTSA proposed the ANSYRESNA WC13-1991 coefficient of hction (COF) test procedure with the following modifications: Procedural Changes to ANSYRESNA WC/13: 1. The test surface area 450 X 100 mm (17.5" X 3.94") is horizontal and clean from dust, dirt ind debris. 2. Pull the test block by a mechanical means to achieve a pull rate of 20 +/- 2 mm/s. 3. Pull the test block for a minimum of 13 seconds and use only the last 10 seconds of force d;i.ta to calculate the average force, which is to have 2% accuracy in the 25N - 100 N range. 4. Collect force data at a frequency of >= 10 Hz. 5. The link between the test block and pulling mechanism shall have a stiffness>= 1 X lo5N/ItI. 6. Evenly spray 3 ml(O.10 02.) of distilled water per 100 cm2(15.5 in2) of test surface area. Begin the test within 30 seconds of the water spray.
v-12 7. Prepare test block fnction surface by lightly abrading with waterproof silicon carbide paper. grade P120, weight D (120 wet and dry). 8. Pull the block in only one direction with pull force parallel to test sample surface. 9. Determine the average pull force from a minimum of five trials over any area. 10. Performance Criterion: Any area of a lift platform surface must have a coefficient of frictil )n >= 0.65 as measured by the test procedure. 11. The lift surface can be tested in any direction using the test block and different surfaces on the same lift platform must meet the same minimum requirements. For further details on the lift platform COF test procedure, a report prepared by the agency ha: been placed in the docket (Docket No. NHTSA-98-45 11) entitled “Evaluation of ANSI/RESPdA WC/13 To Determine the Coefficient of Friction of Wheelchair Lift Platforms, June 6, 1996.” The Final Rule requires that a modified ANSI/RESNA WC/13 test procedure to determine the slip resistance or the coefficient of friction (pp)of WC lift platforms. The agency believes thal this procedure is objective, repeatable, practicable and meets the need for safety. In addition, t is believed that the majority of lifts currently marketed in the U.S. can meet or exceed the requirl :d 0.65 value for pp,when the platform is wet. Platform Markings (S6.4.10) must be slip resistant as well. There could be multiple friction surfaces on a lift platform, therefore, the coefficient I )f friction must be>=0.65 anywhere on the lift platform surface including the platform markings. All lifts come equipped with neoprene rubber mats or other slip resistant surfaces and it is expected that industry would comply, as a whole, without changes or modifications.
Page 1 and 2: Subject: From: To: U.S.Department o
Page 3 and 4: TABLE OF CONTENTS Summary..........
Page 5 and 6: s-2 The annual number of persons in
Page 7 and 8: 11. BACKGROUND 11- 1 Guidelines per
Page 9 and 10: 11-3 and strength; control panel le
Page 11 and 12: 111-2 Generally, there is very litt
Page 13 and 14: 111-4 Table 111-1 Preliminary Natio
Page 15 and 16: 111-6 The NEISS database lacks the
Page 17 and 18: 111-8 Public Transit & Paratransit
Page 19 and 20: w-2 identifying the relevant lift c
Page 21 and 22: IV-4 MEASURE RED FLASHING BEACON OR
Page 23 and 24: IV-6 Acceleration is to be measured
Page 25 and 26: IV-8 FIGURE IV-2 :i a la Y t Permir
Page 27: IV-10 and vehicle size. This requir
Page 31 and 32: IV-14 Gaps, Transitions and Opening
Page 33 and 34: Figure m-3 Allowable transition dim
Page 35 and 36: IV-18 sliding or being driven over
Page 37 and 38: v-20 traveling too fast, in the for
Page 39 and 40: WC Retention Overload Test 67.13) I
Page 41 and 42: IV-24 The lift is raised to the flo
Page 43 and 44: N-26 (2 square inches) applicator a
Page 45 and 46: N-28 sufficient to adequately illum
Page 47 and 48: IV-30 lack of follow-up training. N
Page 49 and 50: IV-32 16. Backup Operation (S6.9) -
Page 51 and 52: IV-34 This “looked but did not se
Page 53 and 54: W-36 e Clearance test block (S7.1.3
Page 55 and 56: IV-38 Structural Integrity, to iden
Page 57 and 58: IV-40 NHTSA assumes that the large,
Page 59 and 60: V. BENEFITS v-1 Serious injuries an
Page 61 and 62: v-3 retention strength test, CG and
Page 63 and 64: v-5 objective terms which should le
Page 65 and 66: VI-2 subject to the ADA requirement
Page 67 and 68: VI-4 averaged 35,000 units per year
Page 69 and 70: VI-6 In order to make an estimate o
Page 71 and 72: Cost Estimates VI-8 New Lift Hardwa
Page 73 and 74: VI- 10 close a circuit and send a s
Page 75 and 76: VI-12 FMVSS No. 141 Lift Certificat
Page 77 and 78: VI- 14 Total Cost for Public-Use Li
Page 79 and 80:
VII. LEADTIME VII-1 Since the lift-
Page 81 and 82:
VIII-2 Table VIII-1 SUMMARY OF SBA
Page 83 and 84:
VIII-4 many private transit bus ope
Page 85 and 86:
VIII-6 Many hundreds of small busin
Page 87 and 88:
VIII-8 adaptive driving equipment f
Page 89 and 90:
VIII-10 Facts Book, 7.2 percent of
Page 91 and 92:
A- 1 REFERENCES 1. Americans with D
Page 93 and 94:
A-3 25. A Directory of UMTA-Funded
Page 95 and 96:
Figure 1 Dirgm Showing the Part8 of
Page 97 and 98:
5 Figure 2. Isometric View of Platf
Page 99 and 100:
PLATFORM DEFLECTION ANGLE DEFLECTIO
Page 101 and 102:
.. Lln UP, OUTER BARRIER UP LIFT MI
Page 103 and 104:
i I i I I I I i 1 i I ! j I I ~ __
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Memorandum - NHTSA

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