[Federal Register Volume 64, Number 220 (Tuesday, November 16, 1999)]
[Proposed Rules]
[Pages 62161-62162]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-29904]


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DEPARTMENT OF TRANSPORTATION

Research and Special Programs Administration

49 CFR Part 178

[Docket No. RSPA-99-5921(HM-213A)]
RIN 2137-AD34


Hazardous Materials: Cargo Tank Rollover Damage Protection 
Requirements

AGENCY: Research and Special Programs Administration (RSPA), DOT.

ACTION: Advance notice of proposed rulemaking (ANPRM).

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SUMMARY: RSPA is requesting comments on a research study conducted by 
the University of Michigan Transportation Research Institute (UMTRI) 
titled ``The Dynamics of Tank-Vehicle Rollover and the Implications for 
Rollover-Protection Devices.'' The intended effect of this action is to 
obtain information concerning the need, if any, for amending the 
Hazardous Materials Regulations (HMR) concerning cargo tank rollover 
damage protection devices, the costs and benefits associated with such 
amendments, and ways to minimize impacts on small businesses. This 
ANPRM addresses DOT specification cargo tanks used for the 
transportation of liquid hazardous materials.

DATES: Comments must be received by May 15, 2000.

ADDRESSES: Submit written comments to the Dockets Management System, 
U.S. Department of Transportation, Room PL. 401, 400 Seventh Street, 
SW, Washington, DC 20590-0001. Comments should identify the docket 
number, RSPA-99-5921 (HM-213A) and submitted in two copies. If you wish 
to receive confirmation that RSPA has received your comments, include a 
self-addressed stamped postcard. Comments may also be submitted to the 
docket electronically by logging onto the Dockets Management System 
website at http://dms.dot.gov. Click on ``Help & Information'' to 
obtain instructions for filing the document electronically.
    The Docket Management System is located on the Plaza Level of the 
Nassif Building at the Department of Transportation at the above 
address. You may review public dockets between the hours of 10 a.m. and 
5 p.m., Monday through Friday, excluding Federal holidays. Internet 
users may review all comments received by the U.S. Department of 
Transportation by accessing RSPA's Hazmat Safety website at http:/
hazmat.dot.gov.

FOR FURTHER INFORMATION CONTACT: Ms. Jennifer Karim, Office of 
Hazardous Materials Standards, Research and Special Programs 
Administration, telephone (202) 366-8553; Mr. Ronald Kirkpatrick, 
Office of Hazardous Materials Technology, Research and Special Programs 
Administration, telephone (202) 366-4545; or Mr. Danny Shelton, Office 
of Safety and Technology; Federal Highway Administration, telephone 
(202) 366-6121, U.S. Department of Transportation, 400 Seventh Street 
SW, Washington, DC.

SUPPLEMENTARY INFORMATION:

I. Background

    Between January and May 1991, the National Transportation Safety 
Board (NTSB) investigated seven highway accidents involving MC 306, MC 
307, and MC 312 specification cargo tank motor vehicles that had 
overturned and released hazardous materials. As a result of these 
investigations, NTSB published a Hazardous Materials Special 
Investigation Report on February 2, 1992. NTSB found that, in all 
cases, the rollover protection devices failed to protect the cargo tank 
manholes and fittings from damage. NTSB reported that in three of the 
accidents structural failure of the rollover protection devices caused 
impact damage to the fittings. In the other four accidents, the design 
and configuration of the devices were found to be inadequate for 
protecting and shielding the top fittings from external objects or from 
striking into the ground. The damaged closures or fittings on top of 
the cargo tank caused the release of hazardous materials during the 
accidents.
    In each case, the rollover protection devices failed to protect the 
cargo tank manholes and fittings from damage sufficient to result in 
loss of lading. The report found that ``* * * there is inadequate 
information about the forces that can be encountered in a rollover 
accident and the extent to which rollover-protection devices for cargo 
tanks can reasonably be designed to withstand these forces * * *'' In 
safety recommendation H-92-10, NTSB recommended that RSPA and the 
Federal Highway Administration (FHWA) conduct a study to analyze the 
forces and energy involved in cargo tank rollover crashes. In response 
to NTSB recommendations, FHWA contracted with the University of 
Michigan Transportation Research Institute (UMTRI) to conduct a study 
on cargo tank rollover protection.

II. UMTRI Study

    The results of UMTRI's study are found in a November 1998 report 
titled ``The Dynamics of Tank-Vehicle Rollover and the Implications for 
Rollover-Protection Devices.'' The study investigated the dynamics of 
mild, moderate and severe rollover crash events involving cargo tank 
motor vehicles. The crash situations and vehicle characteristics were 
influenced by the rollover accidents investigated in the NTSB report. 
These were all DOT specification cargo tank motor vehicles and, in each 
incident, the top damage protection structures were impacted. In the 
UMTRI study, not all simulations resulted in ``rollover'' to this 
degree. Vehicle rotations in which the top damage protection is not 
affected may be more accurately termed ``overturn.'' UMTRI drew 
conclusions from the simulated rollover crashes based on the position 
and speed of each modeled tank at the point when it struck the ground. 
You may obtain copies of the study by calling the Records Center at 
(202) 366-5046, by mailing a request to the Records Center, RSPA, Room 
8421, 400 Seventh Street, SW, Washington, DC 20590, or by downloading 
the study from the DMS electronic docket at http://dms.dot.gov.

III. Request for Comments

    RSPA requests comments responding to the questions listed below to 
facilitate decisions on the potential need for additional changes to 
the HMR with regard to cargo tank rollover damage protection standards. 
Commenters are requested to include information pertaining to their 
experience with damages incurred in other rollover accidents. RSPA also 
invites comments on any aspect of the UMTRI study not specifically 
addressed by questions in this ANPRM. Information, including 
photographs, sketches and accident investigation reports, on rollover 
accidents in which cargo tank manholes and fittings were, or were not, 
damaged would be helpful to RSPA in determining whether to revise the 
current requirements. Similarly, information on release of lading 
through damaged heads or shell is solicited.

A. Impact Scenarios

    Under the heading ``Implications of the Results for Minimum 
Performance Requirements for Rollover-Protection

[[Page 62162]]

Devices,'' the UMTRI report lays out three impact scenarios for 
rollover crashes based on different levels of severity. To restate and 
simplify the rollover events described in B. Rollover Crashes below, 
three scenarios affecting impact were formulated: (1) Mild overturn or 
rollover, (2) moderate rollover, and (3) more severe rollover. In each 
rollover event, it is important to characterize the surface impacted. 
For example, type of surface--was it asphalt, concrete highway paving, 
wet earth, sand, or rocky shoulder materials; angle of surface--was it 
horizontally oriented or did it have an up or down slope; or did the 
vehicle strike a vertical object such as a guardrail, curbing or a tree 
or pole?
    A1. What description of actual accidents can you provide for better 
understanding about the nature of the rollover event?
    A2. What is your judgement of the severity and application of the 
rollover? How can ``severity'' best be characterized?
    A3. How did other accidents that you provided information on differ 
from the simulations performed in the UMTRI study?

B. Rollover Crashes

    The UMTRI study examined the dynamic behavior of cargo tank motor 
vehicles by simulating two straight trucks and five tractor semitrailer 
combinations in rollover events. The study characterized the simulation 
program as follows: ``Each (vehicle) was subjected to 126 simulated 
maneuvers intended to result in rollover. Test maneuvers included mild, 
low-speed turns that just barely produced rollover, more dynamic 
maneuvers on smooth surfaces, and high-speed impacts with curbs and 
guardrails that result in rapid rollover with substantial pitch and 
yaw.'' In mild overturns, the vehicle may fall onto its side and rotate 
no more than 135 degrees, or it may continue to roll on a flat ground 
surface to engage the rollover protection devices. In more severe 
events, the vehicle may land on its side and slide sideways into any of 
the many objects with vertical surfaces that are oriented along the 
roadway; such objects include guardrails, retaining walls and 
embankments. In somewhat more dynamic rollovers, the vehicle may become 
airborne and rotate rapidly enough to bring the rollover protection 
devices into direct contact with the ground. For example, this could 
happen when the vehicle rolls onto a sloping or depressed roadside 
surface or becomes airborne due to striking a curb. On actual rollover 
accidents that you are aware of:
    B1. What was the approximate rollover rate, impact angle, impact 
object, and damage condition of the protection devices?
    B2. Were the accident protection devices impacted during the 
rollover crash? What was the magnitude of the damage to the tank shell, 
fittings, manholes, etc.? What was the damage condition of the 
protective devices?
    B3. Did the rollover protection devices function as designed? If 
not, did they fail because of a design flaw?

C. Rollover Protection Device Performance Goals

    The UMTRI report recommends that performance goals for rollover 
protection devices should be expressed in terms of impact events rather 
than in terms of the strength of the devices. This must include mass, 
velocity and surface parameters. The forces acting on the protection 
devices are the result of an impact. The protection device should be 
designed in such a way as to effectively manage the energy encountered 
by the device during a rollover impact.
    UMTRI suggests that the design of rollover protection devices 
should be able to provide protection when an impact onto a flat surface 
normal to the surface of the cargo tank occurs at velocities of at 
least 12 ft/sec, and further that this occurs at angular orientations 
of the tank with respect to the impact surface which are representative 
of actual incidents. They suggest that impact velocities of up to 24 
ft/sec would be desirable.
    C1. What approach should be used in defining the performance goals 
for rollover protection devices? Should a performance goal be based on 
impact energy absorption and distribution? Should performance testing 
be used to validate calculations?
    C2. What minimum design goals should be required for rollover 
damage protection devices? Should design goals establish a finite space 
into which the protection device could be displaced without contacting 
the protected fittings? Conceptually, should this be done along the 
lines of rear-end protection devices as set forth in Sec. 178.345-
8(d)(1)?
    C3. Should the design goals be based on impact velocity as 
suggested by UMTRI?
    C4. If impact velocity is used, what is an advisable value that 
will cover the majority of accidents?

D. Feasibility of UMTRI Recommendations

    If implemented, the UMTRI recommendations for designing rollover 
protection devices would require more sophisticated analyses on the 
part of cargo tank designers and manufacturers to assure that rollover 
protection devices meet specified performance goals.
    D1. What degree of economic burden, if any, would performance goals 
impose on small businesses such as manufacturers and engineering 
consultants? Would requirements for computerized analysis impose an 
economic burden on small businesses which may be more apt to rely on 
hand calculations?
    D2. Would a standard design, validated to satisfy a given 
performance standard, be an acceptable alternative to a performance 
standard? Would this approach minimize economic impact on small 
business?
    D3. What additional economic burdens might cargo tank designers and 
manufacturers incur if the UMTRI recommendations are adopted?

E. Application to Existing Cargo Tank Motor Vehicles

    If we adopt new rollover protection device design requirements, we 
will need to decide whether and to what extent to apply the new 
requirements to cargo tank motor vehicles that are already in service.
    E1. Should any new performance criteria for rollover damage 
protection devices be applied to cargo tank motor vehicles currently in 
hazardous materials transportation service?
    E2. Should there be a provision proposing new standards for 
rollover damage protection devices which limits the amount of time a 
cargo tank motor vehicle currently in service may be used if it does 
not meet the new requirements?
    E3. Should a retrofit or phase out provision be applicable to all 
cargo tank motor vehicles currently in service or just to cargo tanks 
manufactured under superseded specifications, such as MC 306, MC 307 
and MC 312?
    E4. What economic burden would cargo tank owners incur if they are 
required to retrofit or replace cargo tank motor vehicles that do not 
meet the new performance criteria?

    Issued in Washington, DC on November 10, 1999, under authority 
delegated in 49 CFR part 106.
Alan I. Roberts,
Associate Administrator for Hazardous Materials Safety, Research and 
Special Programs Administration.
[FR Doc. 99-29904 Filed 11-15-99; 8:45 am]
BILLING CODE 4910-60-P