Appendix A to Part 222 - Approved Supplementary Safety Measures
49:4.1.1.1.17.5.15.1.25 : Appendix A
Appendix A to Part 222 - Approved Supplementary Safety Measures A.
Requirements and Effectiveness Rates for Supplementary Safety
Measures
This section provides a list of approved supplementary safety
measures (SSMs) that may be installed at highway-rail grade
crossings within quiet zones for risk reduction credit. Each SSM
has been assigned an effectiveness rate, which may be subject to
adjustment as research and demonstration projects are completed and
data is gathered and refined. Sections B and C govern the process
through which risk reduction credit for pre-existing SSMs can be
determined.
1. Temporary Closure of a Public Highway-Rail Grade
Crossing: Close the crossing to highway traffic during
designated quiet periods. (This SSM can only be implemented within
Partial Quiet Zones.)
Effectiveness: 1.0.
Because an effective closure system prevents vehicle entrance
onto the crossing, the probability of a collision with a train at
the crossing is zero during the period the crossing is closed.
Effectiveness would therefore equal 1. However, analysis should
take into consideration that traffic would need to be redistributed
among adjacent crossings or grade separations for the purpose of
estimating risk following the silencing of train horns, unless the
particular “closure” was accomplished by a grade separation.
Required:
a. The closure system must completely block highway traffic on
all approach lanes to the crossing.
b. The closure system must completely block adjacent pedestrian
crossings.
c. Public highway-rail grade crossings located within New
Partial Quiet Zones shall be closed from 10 p.m. until 7 a.m. every
day. Public highway-rail grade crossings located within Pre-Rule
Partial Quiet Zones may only be closed during one period each 24
hours.
d. Barricdes and signs used for closure of the roadway shall
conform to the standards contained in the MUTCD.
e. Daily activation and deactivation of the system is the
responsibility of the public authority responsible for maintenance
of the street or highway crossing the railroad tracks. The public
authority may provide for third party activation and deactivation;
however, the public authority shall remain fully responsible for
compliance with the requirements of this part.
f. The system must be tamper and vandal resistant to the same
extent as other traffic control devices.
g. The closure system shall be equipped with a monitoring device
that contains an indicator which is visible to the train crew prior
to entering the crossing. The indicator shall illuminate whenever
the closure device is deployed.
Recommended:
Signs for alternate highway traffic routes should be erected in
accordance with MUTCD and State and local standards and should
inform pedestrians and motorists that the streets are closed, the
period for which they are closed, and that alternate routes must be
used.
2. Four-Quadrant Gate System: Install gates at a crossing
sufficient to fully block highway traffic from entering the
crossing when the gates are lowered, including at least one gate
for each direction of traffic on each approach.
Effectiveness:
Four-quadrant gates only, no presence detection: .82.
Four-quadrant gates only, with presence detection: .77.
Four-quadrant gates with traffic of at least 60 feet (with or
without presence detection): .92.
Note:
The higher effectiveness rate for four-quadrant gates without
presence detection does not mean that they are inherently safer
than four-quadrant gates with presence detection. Four-quadrant
gates with presence detection have been assigned a lower
effectiveness rate because motorists may learn to delay the
lowering of the exit gates by driving onto the opposing lane of
traffic immediately after an opposing car has driven over the grade
crossing. Since the presence detection will keep the exit gate
raised, other motorists at the crossing who observe this scenario
may also be tempted to take advantage of the raised exit gate by
driving around the lowered entrance gates, thus increasing the
potential for a crossing collision.
It should, however, be noted that there are site-specific
circumstances (such as nearby highway intersections that could
cause traffic to back up and stop on the grade crossing), under
which the use of presence detection would be advisable. For this
reason, the various effectiveness rates assigned to four-quadrant
gate systems should not be the sole determining factor as to
whether presence detection would be advisable. A site-specific
study should be performed to determine the best application for
each proposed installation. Please refer to paragraphs (f) and (g)
for more information.
Required:
Four-quadrant gate systems shall conform to the standards for
four-quadrant gates contained in the MUTCD and shall, in addition,
comply with the following:
a. When a train is approaching, all highway approach and exit
lanes on both sides of the highway-rail crossing must be spanned by
gates, thus denying to the highway user the option of circumventing
the conventional approach lane gates by switching into the opposing
(oncoming) traffic lane in order to enter the crossing and cross
the tracks.
b. Crossing warning systems must be activated by use of constant
warning time devices unless existing conditions at the crossing
would prevent the proper operation of the constant warning time
devices.
c. Crossing warning systems must be equipped with power-out
indicators.
Note:
Requirements b and c apply only to New Quiet Zones or New
Partial Quiet Zones. Constant warning time devices and power-out
indicators are not required to be added to existing warning systems
in Pre-Rule Quiet Zones and Pre-Rule Partial Quiet Zones. However,
if existing automatic warning device systems in Pre-Rule Quiet
Zones and Pre-Rule Partial Quiet Zones are renewed, or new
automatic warning device systems are installed, power-out
indicators and constant warning time devices are required, unless
existing conditions at the crossing would prevent the proper
operation of the constant warning devices.
d. The gap between the ends of the entrance and exit gates (on
the same side of the railroad tracks) when both are in the fully
lowered, or down, position must be less than two feet if no median
is present. If the highway approach is equipped with a median or a
channelization device between the approach and exit lanes, the
lowered gates must reach to within one foot of the median or
channelization device, measured horizontally across the road from
the end of the lowered gate to the median or channelization device
or to a point over the edge of the median or channelization device.
The gate and the median top or channelization device do not have to
be at the same elevation.
e. “Break-away” channelization devices must be frequently
monitored to replace broken elements.
Recommendations for new installations only:
f. Gate timing should be established by a qualified traffic
engineer based on site specific determinations. Such determination
should consider the need for and timing of a delay in the descent
of the exit gates (following descent of the conventional entrance
gates). Factors to be considered may include available storage
space between the gates that is outside the fouling limits of the
track(s) and the possibility that traffic flows may be interrupted
as a result of nearby intersections.
g. A determination should be made as to whether it is necessary
to provide vehicle presence detectors (VPDs) to open or keep open
the exit gates until all vehicles are clear of the crossing. VPD
should be installed on one or both sides of the crossing and/or in
the surface between the rails closest to the field. Among the
factors that should be considered are the presence of intersecting
roadways near the crossing, the priority that the traffic crossing
the railroad is given at such intersections, the types of traffic
control devices at those intersections, and the presence and timing
of traffic signal preemption.
h. Highway approaches on one or both sides of the highway-rail
crossing may be provided with medians or channelization devices
between the opposing lanes. Medians should be defined by a
non-traversable curb or traversable curb, or by reflectorized
channelization devices, or by both.
i. Remote monitoring (in addition to power-out indicators, which
are required) of the status of these crossing systems is
preferable. This is especially important in those areas in which
qualified railroad signal department personnel are not readily
available.
3. Gates With Medians or Channelization Devices: Install
medians or channelization devices on both highway approaches to a
public highway-rail grade crossing denying to the highway user the
option of circumventing the approach lane gates by switching into
the opposing (oncoming) traffic lane and driving around the lowered
gates to cross the tracks.
Effectiveness:
Channelization devices - .75.
Non-traversable curbs with or without channelization devices -
.80.
Required:
a. Opposing traffic lanes on both highway approaches to the
crossing must be separated by either: (1) medians bounded by
non-traversable curbs or (2) channelization devices.
b. Medians or channelization devices must extend at least 100
feet from the gate arm, or if there is an intersection within 100
feet of the gate, the median or channelization device must extend
at least 60 feet from the gate arm.
c. Intersections of two or more streets, or a street and an
alley, that are within 60 feet of the gate arm must be closed or
relocated. Driveways for private, residential properties (up to
four units) within 60 feet of the gate arm are not considered to be
intersections under this part and need not be closed. However,
consideration should be given to taking steps to ensure that
motorists exiting the driveways are not able to move against the
flow of traffic to circumvent the purpose of the median and drive
around lowered gates. This may be accomplished by the posting of
“no left turn” signs or other means of notification. For the
purpose of this part, driveways accessing commercial properties are
considered to be intersections and are not allowed. It should be
noted that if a public authority can not comply with the 60 feet or
100 feet requirement, it may apply to FRA for a quiet zone under §
222.39(b), “Public authority application to FRA.” Such arrangement
may qualify for a risk reduction credit in calculation of the Quiet
Zone Risk Index. Similarly, if a public authority finds that it is
feasible to only provide channelization on one approach to the
crossing, it may also apply to FRA for approval under § 222.39(b).
Such an arrangement may also qualify for a risk reduction credit in
calculation of the Quiet Zone Risk Index.
d. Crossing warning systems must be activated by use of constant
warning time devices unless existing conditions at the crossing
would prevent the proper operation of the constant warning time
devices.
e. Crossing warning systems must be equipped with power-out
indicators. Note: Requirements d and e apply only to New Quiet
Zones and New Partial Quiet Zones. Constant warning time devices
and power-out indicators are not required to be added to existing
warning systems in Pre-Rule Quiet Zones or Pre-Rule Partial Quiet
Zones. However, if existing automatic warning device systems in
Pre-Rule Quiet Zones and Pre-Rule Partial Quiet Zones are renewed,
or new automatic warning device systems are installed, power-out
indicators and constant warning time devices are required, unless
existing conditions at the crossing would prevent the proper
operation of the constant warning devices.
f. The gap between the lowered gate and the curb or
channelization device must be one foot or less, measured
horizontally across the road from the end of the lowered gate to
the curb or channelization device or to a point over the curb edge
or channelization device. The gate and the curb top or
channelization device do not have to be at the same elevation.
g. “Break-away” channelization devices must be frequently
monitored to replace broken elements.
4. One Way Street with Gate(s): Gate(s) must be installed
such that all approaching highway lanes to the public highway-rail
grade crossing are completely blocked.
Effectiveness: .82.
Required:
a. Gate arms on the approach side of the crossing should extend
across the road to within one foot of the far edge of the pavement.
If a gate is used on each side of the road, the gap between the
ends of the gates when both are in the lowered, or down, position
must be no more than two feet.
b. If only one gate is used, the edge of the road opposite the
gate mechanism must be configured with a non-traversable curb
extending at least 100 feet.
c. Crossing warning systems must be activated by use of constant
warning time devices unless existing conditions at the crossing
would prevent the proper operation of the constant warning time
devices.
d. Crossing warning systems must be equipped with power-out
indicators.
Note:
Requirements c and d apply only to New Quiet Zones and New
Partial Quiet Zones. Constant warning time devices and power-out
indicators are not required to be added to existing warning systems
in Pre-Rule Quiet Zones or Pre-Rule Partial Quiet Zones. If
automatic warning systems are, however, installed or renewed in a
Pre-Rule Quiet or Pre-Rule Partial Quiet Zone, power-out indicators
and constant warning time devices shall be installed, unless
existing conditions at the crossing would prevent the proper
operation of the constant warning time devices.
5. Permanent Closure of a Public Highway-Rail Grade
Crossing: Permanently close the crossing to highway
traffic.
Effectiveness: 1.0.
Required:
a. The closure system must completely block highway traffic from
entering the grade crossing.
b. Barricades and signs used for closure of the roadway shall
conform to the standards contained in the MUTCD.
c. The closure system must be tamper and vandal resistant to the
same extent as other traffic control devices.
d. Since traffic will be redistributed among adjacent crossings,
the traffic counts for adjacent crossings shall be increased to
reflect the diversion of traffic from the closed crossing.
B. Credit for Pre-Existing SSMs in New Quiet Zones and New Partial
Quiet Zones
A community that has implemented a pre-existing SSM at a public
grade crossing can receive risk reduction credit by inflating the
Risk Index With Horns as follows:
1. Calculate the current risk index for the grade crossing that
is equipped with a qualifying, pre-existing SSM. (See appendix D.
FRA's web-based Quiet Zone Calculator may be used to complete this
calculation.)
2. Adjust the risk index by accounting for the increased risk
that was avoided by implementing the pre-existing SSM at the public
grade crossing. This adjustment can be made by dividing the risk
index by one minus the SSM effectiveness rate. (For example, the
risk index for a crossing equipped with pre-existing channelization
devices would be divided by .25.)
3. Add the current risk indices for the other public grade
crossings located within the proposed quiet zone and divide by the
number of crossings. The resulting risk index will be the new Risk
Index With Horns for the proposed quiet zone.
C. Credit for Pre-Existing SSMs in Pre-Rule Quiet Zones and
Pre-Rule Partial Quiet Zones
A community that has implemented a pre-existing SSM at a public
grade crossing can receive risk reduction credit by inflating the
Risk Index With Horns as follows:
1. Calculate the current risk index for the grade crossing that
is equipped with a qualifying, pre-existing SSM. (See appendix D.
FRA's web-based Quiet Zone Calculator may be used to complete this
calculation.)
2. Reduce the current risk index for the grade crossing to
reflect the risk reduction that would have been achieved if the
locomotive horn was routinely sounded at the crossing. The
following list sets forth the estimated risk reduction for certain
types of crossings:
a. Risk indices for passive crossings shall be reduced by
43%;
b. Risk indices for grade crossings equipped with automatic
flashing lights shall be reduced by 27%; and
c. Risk indices for gated crossings shall be reduced by 40%.
3. Adjust the risk index by accounting for the increased risk
that was avoided by implementing the pre-existing SSM at the public
grade crossing. This adjustment can be made by dividing the risk
index by one minus the SSM effectiveness rate. (For example, the
risk index for a crossing equipped with pre-existing channelization
devices would be divided by .25.)
4. Adjust the risk indices for the other crossings that are
included in the Pre-Rule Quiet Zone or Pre-Rule Partial Quiet Zone
by reducing the current risk index to reflect the risk reduction
that would have been achieved if the locomotive horn was routinely
sounded at each crossing. Please refer to step two for the list of
approved risk reduction percentages by crossing type.
5. Add the new risk indices for each crossing located within the
proposed quiet zone and divide by the number of crossings. The
resulting risk index will be the new Risk Index With Horns for the
quiet zone.