Federal Register / Vol. 61, No. 106 / Friday, May 31, 1996 / Proposed Rules 27325

a Class IIb, Class IIc or Class U (as

identified in Pettyjohn et al., 1991; EPA

Document: EPA/600/2–91/043, August

1991; see Attachment A), the public

water systems that rely on these aquifers

shall not be designated as USAs.

Filter Criteria #5: For CWS and

NTNCWS that obtain their water supply

primarily from ground water sources,

where the source aquifer is identified as

a Class I or Class IIa (as identified in

Pettyjohn et al., 1991; EPA Document:

EPA/600/2–91/043, August 1991; see

Attachment A), and the aquifer is

designated as a sole source aquifer, an

area twice the WHPA shall be

designated as an USA.

Issued in Washington, DC, on May 23,

1966.

Richard B. Felder,

Associate Administrator for Pipeline Safety.

Attachment A

Recommended Data Source: EPA Report

600/2–91/043. Regional Assessment of

Aquifer Vulnerability and Sensitivity in the

Conterminous United States. Office of

Research and Development, Washington, DC.

319pp.

The following information was obtained

from pages 6–8 of the above report:

CLASS I AQUIFERS (Surficial or shallow,

permeable units; highly vulnerable to

contamination).

Unconsolidated Aquifers (Class Ia): Class la

aquifers consist of surficial, unconsolidated,

and permeable alluvial, terrace, outwash,

beach, dune and other similar deposits.

These units generally contain layers of sand

and gravel that, commonly, are interbedded

to some degree with silt and clay. Not all

deposits mapped as Class la are important

water-bearing units, but they are likely to be

both permeable and vulnerable. The only

natural protection of aquifers of this class is

the thickness of the unsaturated zone and the

presence of fine-grained material.

Soluble and Fractured Bedrock Aquifers

(Class Ib): Lithologies in this class include

limestone, dolomite, and locally, evaporitic

units that contain documented karst features

or solution channels, regardless of size.

Generally these systems have a wide range in

permeability * * * Also included in this

class are sedimentary strata, and

metamorphic and igneous (intrusive and

extrusive) rocks that are significantly faulted,

fractured, or jointed. In all cases groundwater

movement is largely controlled by secondary

openings. Well yields range widely, but the

important feature is the potential for rapid

vertical and lateral ground water movement

along preferred pathways, which result in a

high degree of vulnerability.

Semiconsolidated Aquifers (Class Ic):

Semiconsolidated systems generally contain

poorly to moderately indurated sand and

gravel that is interbedded with clay and silt.

This group is intermediate to the

unconsolidated and consolidated end

members. These systems are common in the

Tertiary age rocks that are exposed

throughout the Gulf and Atlantic coastal

states. Semiconsolidated conditions also

arise from the presence of intercalated clay

and caliche within primarily unconsolidated

to poorly consolidated units, such as occurs

in parts of the High Plains Aquifer.

Covered Aquifers (Class Id): This class

consists of any Class I aquifer that is overlain

by less than 50 feet of low permeability,

unconsolidated material, such as glacial till,

lacustrian, and loess deposits.

CLASS II AQUIFERS (Consolidated

bedrock aquifers; moderately vulnerable).

Higher Yield Bedrock Aquifers (Class IIa):

These aquifers generally consist of fairly

permeable sandstone or conglomerate that

contain lesser amounts of interbedded fine

grained clastics (shale, siltstone, mudstone)

and occasionally carbonate units. In general,

well yields must exceed 50 gpm to be

included in this class. Locally fracturing may

contribute to the dominant primary porosity

and permeability of these systems.

Lower Yield Bedrock Aquifers (Class IIb):

In most cases, these aquifers consist of

sedimentary or crystalline rocks. Most

commonly, lower yield systems consist of the

same classic rock types present in the higher

yield systems, but in the former case grain

size is generally smaller and the degree of

cementation or induration is greater, both of

which lead to a lower permeability. In many

existing and ancient mountain regions, such

as the Appalachians (Blue Ridge and

Piedmont), the core consists of crystalline

rocks that are fractured to some degree. Well

yields are commonly less than 50 gpm,

although they may be larger in valleys than

on interstream divides.

Covered Bedrock Aquifers (Class IIc): This

group consists of Class IIa and IIb aquifers

that are overlain by less than 50 feet of

unconsolidated material of loq permeability,

such as glacial till, lacustrian, or loess

deposits. It is assumed that most Class V

wells are relatively shallow and, therefore, 50

feet or less of fine grained cover could reduce

but not necessarily eliminate the

vulnerability of underlying Class II systems.

CLASS III (Consolidated or unconsolidated

aquifers that are overlain by more than 50

feet of low permeability material; low

vulnerability).

Aquifers of this type are the least

vulnerable of all the classes because they are

naturally protected by a thick layer of fine

grained material, such as glacial till or shale.

Examples include parts of the Northern Great

Plains where the Pierre Shale of Cretaceous

age crops out over thousands of square miles

and is hundreds of feet thick. In many of the

glaciated states, till forms an effective cover

over bedrock or buried outwash aquifers, and

elsewhere alternating layers of shale,

siltstone, and fine grained sandstone insulate

and protect the deeper major water bearing

zones * * *

CLASS U (Undifferentiated aquifers): This

classification is used where several lithologic

and hydrologic conditions are present within

a mappable area. Units are assigned to this

class because of constraints of mapping scale,

the presenece of undelineated members

within a formation or group, or the presence

of nonuniformly occurring features, such as

fracturing. This class is intended to convey

a wider range of vulnerability than is usually

contained within any other single class.

SUBCLASS V (Variable covered aquifers):

The modifier ‘‘v’’, such as Class IIa–v, is used

to describe areas where an undetermined or

highly variable thickness of low permeability

sediments overlie the major water bearing

zone. To provide the largest amount of

information, the underlying aquifer was

mapped as if the cover were absent, and the

‘‘v’’ designation was added to the

classification. The ‘‘v’’ indicates that a

variable thickness of low permeability

material covers the aquifer and, since the

thickness of the cover, to a large degree,

controls vulnerability, this aspect is

undefined.

[FR Doc. 96–13530 Filed 5–30–96; 8:45 am]

BILLING CODE 4910–60–M

National Highway Traffic Safety

Administration

49 CFR Part 571

[Docket No. 96–51, Notice 01]

RIN 2127–AG16

Federal Motor Vehicle Safety

Standards Door Locks and Door

Retention Components

AGENCY: National Highway Traffic

Safety Administration (NHTSA),

Department of Transportation (DOT).

ACTION: Grant of petition for rulemaking.

SUMMARY: This notice grants a petition

for rulemaking submitted by

Independent Mobility Systems, Inc.

(IMS), to exclude wheelchair ramps

from the Federal motor vehicle safety

standard that establishes performance

requirements for door locks and door

retention components. Since side doors

equipped with wheelchair lifts are

excluded from the standard, the

petitioner requests that the standard be

amended to also exclude side doors

equipped with wheelchair ramps.

NHTSA believes that the amendment

suggested by IMS merits further

research and study. To that extent,

therefore, the agency grants IMS’

petition. The granting of this petition,

however, does not necessarily mean that

a rule will be issued.

The determination of whether to issue

a rule will be made in the course of the

rulemaking proceeding in accordance

with statutory criteria.

FOR FURTHER INFORMATION CONTACT: For

technical issues: Mr. Maurice Hicks,

Light Duty Vehicle Division, Office of

Crashworthiness Standards, National

Highway Traffic Safety Administration,

400 Seventh Street, SW., Washington,

DC 20590; telephone (202) 366–6345;

facsimile (202) 366–4329.

For legal issues: Walter Myers, Office

of the Chief Counsel, National Highway
27326 Federal Register / Vol. 61, No. 106 / Friday, May 31, 1996 / Proposed Rules

Traffic Safety Administration,

Washington, DC 20590; telephone (202)

366–2992; facsimile (202) 366–3820.

SUPPLEMENTARY INFORMATION: Federal

motor vehicle safety standard (Standard)

No. 206, Door locks and door retention

components, specifies strength

requirements for door locks and door

retention components, including

latches, hinges, locks, and other door

supporting means. The purpose of the

standard is to minimize the likelihood

of inadvertent door opening and

consequent occupant ejection from the

vehicle in the event of a crash or other

unintended release of the door latch.

Excluded from the requirements of the

standard are, among others:

[S]ide doors which are equipped with

wheelchair lifts and which are linked to an

alarm system consisting of either a flashing

visible signal located in the driver’s

compartment or an alarm audible to the

driver which is activated when the door is

open.

This exclusion was added to

paragraph S4 of the standard by final

rule dated March 27, 1985 (50 FR

12029), in response to a petition for

rulemaking submitted by Thomas Built

Buses, Inc. The agency’s rationale for

excluding doors equipped with

wheelchair lifts was that when lifts of

the Thomas Built design were retracted,

they were secured in position by either

hydraulic pressure in the extension/

retraction cylinders and mechanical

latches, or by electrically-operated drive

mechanisms. The metal grate floors of

the lifts were stowed in a vertical

position parallel to and in close

proximity with the interior surface of

the vehicle door. Thus, in its retracted

position, the wheelchair lift could

provide an adequate barrier to occupant

ejection from the vehicle if the door

were to open while the vehicle was

moving or if involved in a collision. The

final rule also required a visual or

audible alarm system designed to be

activated if the door opened while the

ignition was on. Such alarm would

ensure that the lift is kept in its

retracted position and the door is kept

closed while the vehicle is in operation.

On May 18, 1995, IMS wrote a letter

to NHTSA stating that the company

converts minivans into wheelchair

accessible vehicles by lowering the

vehicle floor and adding a wheelchair

ramp to the right rear sliding door area.

The ramp retracts into a vertical

position parallel to and in close

proximity to the vehicle door when not

in use. IMS also equips the doors with

an audible and/or visual alarm system.

IMS asked, therefore, whether the

exclusion of wheelchair lifts from the

provisions of Standard No. 206 would

also apply to the wheelchair ramps with

which IMS equips its vehicle

conversions. NHTSA responded that the

term ‘‘wheelchair lifts’’ did not include

wheelchair ramps. The agency noted

that the two components shared many

similar characteristics, however, and

that IMS was free to petition the agency

for rulemaking to amend the standard

by adding wheelchair ramps to the

current exclusions from the standard.

The Petition

IMS petitioned the agency to amend

Standard No. 206 to exclude from the

standard those multipurpose passenger

vehicles (MPV) that are equipped with

wheelchair ramps for the transportation

of wheelchair users. IMS argued that

because wheelchair lifts and ramps

serve the same purpose and are

similarly configured when in the stowed

position, the rationale for excluding

wheelchair lifts from the standard

should also apply to wheelchair ramps.

Accordingly, IMS urged that paragraph

S4 of the standard be amended to

exclude wheelchair ramps from the

standard in addition to the existing

exclusions.

Agency Analysis and Decision

The IMS petition requesting exclusion

of ramps from the standard is based on

the similarity of performance

characteristics of wheelchair lifts and

ramps. NHTSA evaluation, however,

has revealed several structural

differences between the IMS ramp and

the Thomas Built lift on which the

current exclusion was based. In fact,

most ramps and lifts currently produced

are structurally different from the

Thomas Built lift.

A schematic of the IMS ramp is

shown in Figure 1. The IMS ramp

operates much like a lift, in that it

retracts into the vehicle in a vertical

position that is parallel to and in close

proximity of the vehicle door. However,

in its retracted position, the ramp can

detach and swing open like a gate to

permit ingress and egress of ambulatory

people, with a latch at the lower part of

the gate to hold it in place. Finally, the

IMS ramp in question, when in the

retracted position, does not completely

cover the doorway opening. The ramp

folds into the vehicle to a position that

covers from one-half to three- fourths of

the doorway, the intent being to avoid

obstructing the driver’s vision to the

side.

NHTSA’s evaluation of the lift and

ramp designs revealed a wide variety of

lift and ramp designs produced by other

manufacturers, including those that

retract under the vehicle, those that

suspend within the door sill (which lifts

the wheelchair user by means of a

pulley), those that retract within the

vehicle parallel to the floor, and some

that are, like the IMS ramp, detachable

from at least one side. Also like the IMS

ramp, many lifts and ramps produced

by other manufacturers do not cover the

entire door.

In order to install the IMS ramp in a

vehicle, the vehicle is altered by

lowering the floor between the firewall

and the rear axle. This alteration is

commonly performed on most lift/rampequipped vans and MPVs. The original

floor is replaced with an interior panel

of 16-gauge steel and an exterior panel

of 18-gauge steel. Both are hollow zmember panels which together have an

equivalent thickness of one inch. The

lower edge of the side sliding door is

extended to meet the lowered floor and

the lower track of the sliding door is

refitted to accommodate the larger door.

Structurally, the sliding track guide is

similar to the vehicle’s original track

guide for non-electric doors. For electric

doors, however, the design is

significantly different. Specifically, the

installation of the electric IMS ramp

requires that the latch be disabled to

accommodate the electric track closing

and opening the door.

Because of the many different designs

of wheelchair lifts and ramps currently

being produced, the agency is

concerned that its exclusion of

wheelchair lifts from the requirements

of the standard, based on the thencurrent Thomas Built design, may be

overly broad. At the same time, the

agency believes that wheelchair ramps

and lifts are essential to the safe and

efficient transportation of persons with

disabilities. Accordingly, the change

requested by IMS warrants further

investigation and research into the

installation and manner of operation of

the various wheelchair lift and ramp

designs currently in production, with a

view toward adoption of uniform

criteria for both. To that extent,

therefore, the agency grants the IMS

petition.

The granting of the IMS petition,

however, does not necessarily mean that

a rule will be issued. The determination

of whether to issue a rule is made after

study of the requested action and the

various alternatives thereto in the

course of the rulemaking proceeding, in

accordance with statutory criteria.

List of Subjects in 49 CFR Part 571

Imports, Motor vehicle safety, Motor

vehicles, Rubber and rubber products,

Tires.
Federal Register / Vol. 61, No. 106 / Friday, May 31, 1996 / Proposed Rules 27327

Authority: 49 U.S.C. §§ 322, 30111, 30115,

30117, and 30166; delegation of authority at

49 CFR 1.50.

BILLING CODE 4910–59–P
27328 Federal Register / Vol. 61, No. 106 / Friday, May 31, 1996 / Proposed Rules
Federal Register / Vol. 61, No. 106 / Friday, May 31, 1996 / Proposed Rules 27329

Issued on May 27, 1996.

Barry Felrice,

Associate Administrator for Safety

Performance Standards.

[FR Doc. 96–13711 Filed 5–30–96; 8:45 am]

BILLING CODE 4910–59–C