Number range CHAPTER**["Train Horn Rule" Glossary]{.underline}**

**Quiet Zone:** A quiet zone is a section of a rail line that contains
one or more consecutive public crossings at which locomotive horns are
not routinely sounded.

**Alternative Safety Mea**s**ure (ASM):**

**Public Highway-Rail (Grade) Crossing:** A location where a public
highway, road, or street crosses railroad tracks at grade. For this
rule, This includes crossings where a public authority maintains the
roadway on at least one side of the crossing.

**Private Highway-Rail (Grade) Crossing:** A location where a private
roadway crosses railroad tracks at grade.

**Diagnostic Team:** A group of qualified or specially-trained
individuals assembled to make objective expert judgements about physical
and or operating conditions at highway-rail crossings. In the context of
this rule, a diagnostic team assesses grade crossing safety requirements
according to safety management principles.

**E.O. 15 (Emergency Order 15):** Emergency Order 15, issued in 1991,
requires the Florida East Coast Railroad (FEC) to sound locomotive horns
at all public highway-rail grade crossings. The Emergency Order
preempted state and local laws that permitted nighttime prohibitions on
the use of locomotive horns.

**Environmental Impact Statement (EIS):** Environmental Impact
Statements are required of federal agencies for major projects or
legislative proposals that may significantly affect the environment.
These statements describe the positive and negative effects of the
proposed undertaking and cite possible alternative actions. Impact
Statements are required by the National Environmental Policy Act. The
EPA reviews and responds to filed impact statements and makes available
a national EIS filing system as well as publishing a weekly notice of
EIS documents available for review.

**MUTCD:** *The Manual on Uniform Traffic Control Devices*; a guidance
document published by the Federal Highway Administration (FHWA)
establishing specifications for highway signs, signals, and pavement
markings.

The Manual on Uniform Traffic Control Devices, a guidance document
published by the Federal Highway Administration establishing
specifications for highway signs, signals, and pavement markings.

**FAA Reauthorization Act of 1996:** This legislation added two
paragraphs to 49 U.S.C. 20153 (the section of the United States Code
requiring this rulemaking). One paragraph required that FRA take into
account the interests of communities that had whistle bans in effect
during a specified time period. The second required that any rule issued
under section 20153 can not be effective until at least 365 days after
its publication in the Federal Register.

**Final Environmental Impact Statement (FEIS):**

**Supplementary Safety Measure (SSM):** SSMs are engineering
improvements, which when installed at crossings within a quiet zone,
would reduce the risk of a collision at the crossing. SSMs are installed
to reduce the risk level either to the level that would have existed if
the train horn were sounded (compensating for the lack of the train
horn) or to a level below the Nationwide Significant Risk Threshold.

> Approved SSMs include:

1.  Four quadrant gates.

2.  Medians or channelization devices at gated crossings.

3.  One-way streets equipped with gates that fully block the street.

4.  Temporary closure (i.e., nighttime closure).

**Four-Quadrant Gate:** Train-activated warning gates that, when
lowered, fully block highway traffic from entering the crossing. Gates
lower across both approach and departure lanes on both sides of the
crossing.

**Interim Final Rule:**

**Alternative Safety Measure (ASM):** A safety system or procedure
provided by the appropriate traffic control authority which, after
individual review and analysis, is determined by the FRA to be an
effective substitute for the locomotive horn at specific crossings.

> ASMs include:

5.  Modified SSMs (see definition)

6.  Programmatic law enforcement

7.  Programmatic education

8.  Photo enforcement

**Modified SSM:** An SSM that has in some way been adjusted to
accommodate unique circumstances existing at a specific crossing and no
longer conforms to the SSM requirements. Modified SSMs are considered
ASMs. An example would be traffic channelization devices that due to a
nearby intersection are only 45 feet in length instead of the required
60 feet.

**MUTCD:**

**Non-engineering ASM:** A consistent and systematic program of traffic
law enforcement, public education programs, or a combination thereof,
that produces a measurable reduction of risk at quiet zone grade
crossings.

**NSRT:**

**Public Highway-Rail (Grade) Crossing:**

Private Highway-Rail (Grade) Crossing:

Quiet Zone: A quiet zone is a section of a rail line that contains one
or more consecutive public crossings at which locomotive horns are not
routinely sounded. This rule provides the requirements that must be met
in order to qualify for a quiet zone. For example, New Quiet Zones must
be at least one-half mile in length. (Section 222.9 - definition of a
quiet zone)

**Risk Index:** The predicted cost to society of casualties that are
expected to result from collisions at an individual crossing.

**Quiet Zone Risk Index:** The average risk index for all public
crossings in a proposed quiet zone taking into consideration the
increased risk caused by the absence of train horns and any decrease in
risk attributable to the use of SSMs or ASMs..

**NSRT:** The Nationwide Significant Risk Threshold, an is the average
Risk Index of all public, gated crossings in the nation at which train
horns are sounded.

**Supplementary Safety Measure (SSM):** SSMs are engineering
improvements, which when installed at crossings within a quiet zone,
would reduce the risk of a collision at the crossing. SSMs are installed
to reduce the risk level either to the level that would have existed if
the train horn were sounded (compensating for the lack of the train
horn) or to a level below the Nationwide Significant Risk Threshold.

> Approved SSMs include:

Four quadrant gates. Medians or channelization devices at gated
crossings.

One-way streets. Temporary closure (i.e., nighttime closure).

**Wayside Horn or Directional Horn or Automated Horn System:** A
stationary horn located at a highway-rail grade crossing that is
designed to provide audible warning to oncoming motorists when a train
is approaching. The horn is controlled by the same track circuits that
operate the automatic warning devices at the crossing.

***Whistle ban* or Pre-Rule Quiet Zone:** A *whistle* *ban* is a local
prohibition of the sounding of locomotive horns at specific highway-rail
grade crossings. Historically*, Whistle* *bans* were established by
local ordinance or through agreements with specific railroads in
accordance with existing state law. At whistle ban crossings, no
specific safety improvements have been made to compensate for the
absence of the audible warning. Pre-Rule Quiet Zones established under
this rule may only consist of Whistle Ban crossings that were in effect
on October 9, 1996 and on December 18, 2003.

**Relevant collision:** A highway-rail crossing collision that FRA
believes could be prevented by sounding the train horn. Specifically,
the term excludes collisions with motor vehicles resulting from an
activation failure of an active grade crossing warning system;
collisions in which there is no driver in the motor vehicle; and
collisions where the highway vehicle struck the side of the train beyond
the fourth locomotive unit or rail car. means a collision at a
highway-rail grade crossing between a train and a motor vehicle,
excluding the following: a collision resulting from an activation
failure of an active grade crossing warning system; a collision in which
there is no driver in the motor vehicle; or a collision where the
highway vehicle struck the side of the train beyond the fourth
locomotive unit or rail car.