office is contacted many times a month regarding a parking lot control
arm or barrier gate injury of some sort. These terms are generally
interchangeable; however, some standards do not use the term control
arm, only barrier arm. Usually, the attorney starts by explaining that
the plaintiff was hit by a descending parking lot arm without any
advance warning. Sometimes the injured party is riding a motorcycle,
sometimes walking as a pedestrian under the arm. In other claims the
gate arm does not fully cycle open before returning to the horizontal
position. There are also cases where the gate appears to have been left
in an open position, turned off, and is remaining in the upright
position for extended periods of time and suddenly descends just as a
pedestrian begins to pass under it. There are numerous variations of the
same type of accident, but there are big differences in who the
responsible party is for the cause of injury. Some of the first
questions asked pertain to how the device works, and why the arm did not
detect the person as they walked through the driveway.
FULLY AUTOMATED OR ATTENDED, BOTH SHARE SOME CHARACTERISTICS
of most barrier arm gates build their devices to activate in one of two
different ways. Fully automated by remote stimulus and/or manually
controlled by a parking lot attendant.
Many parking lot control
arms are activated when a driver pulls up to a parking lot gate in a
vehicle. As the vehicle arrives, an electronic signal is sent to the arm
mechanism due to the detection of that vehicles large metallic presence
interacting with an in-ground magnetic field. This
magnetic field is created from buried wires known in the trade as an
induction loop. The signal generated from this “activation or approach
magnetic induction flux loop” often is connected to a ticket printing
device. This piece of equipment is commonly referred to as a “Ticket
Spitter”. The “Spitter” issues a ticket, usually for single vehicle
access prior to activating the barrier arm gate mechanism causing the
arm to raise. An alternative method to get the control arm raised
requires a driver to reach out of the car and push a button to receive a
parking lot access ticket from the “Spitter”. (In that mode of
operation, it is probable that there is no magnetic loop in place.) In
either case, once the ticket is taken by the driver, the “Spitter” sends
a control signal to the gate arm mechanism, and the arm is supposed to
raise, generally for a single vehicle to control access to the parking
As the vehicle transitions from the approach location where
the ticket is issued, once the control arm raises, there is usually a
functioning magnetic flux or induction “Safety Loop” located under the
control arm swing location which provides protection for a vehicle until
it has cleared the “Zone of Danger” underneath the active arm. The
control arm may also be kept in the open position by a timer that holds
the gate arm up for a predetermined time prior to closing. Using a timer
function in place of an in-ground magnetic loop is risky, as vehicles
may not clear the opening, or another vehicle can attempt to gain access
without receiving a usage ticket. Older, non-current standard compliant
installations have been seen without any consistency of design or
There are multiple installation variables
that can alter the basic loop positions and quantities, but most basic
systems operate as described above using at least two control loops. One
underneath the control arm, and one egress or approach loop. In some
installations, all three loops will be present. This triple looped
system offers the most comprehensive safety for a vehicle, NOT A
MANUAL VERSIONS OF PARKING LOT CONTROL ARMS
parking lot attendant, usually positioned inside an adjacent booth, has
a control switch that activates the parking arm. The attendant has a
switch that raises the arm, lowers the arm, and keeps the arm inactive,
either up or down. Some manually controlled arms also have magnetic
induction loops connected to the parking lot control arm when the
parking lot is unmanned after hours, in which case, the arm should
function in the fully automatic mode, as described above.
BARRIER ARMS ARE WEIGHT ACTIVATED, RIGHT?
to popular belief, most are activated due to a change in a magnetic
field which is generated by twisted energized wires positioned below the
adjacent pavement of the control arm. Modern arms are not usually
controlled by pneumatic pressure like an old-fashioned gas station bell
hose. It is unlikely that the weight of a vehicle or a pedestrian
walking underneath the arm will stop an active arm. Modern parking arms
are triggered by a change in the magnetic induction loop return. Modern
induction loops are manufactured from a relatively light gauge of wire,
placed in a rectangular shape that is calibrated and sized to detect a
change in the magnetic field when a metallic object such as a vehicle
enters or covers that field.
Many attorneys insist to me during
their initial call that a pedestrian walked next one and activated the
arm due to their client’s weight, and the arm failed to remain open as
they walked under the arm. This scenario is generally incorrect. Weight
of a vehicle, or weight of a pedestrian cannot activate most modern
parking control arms. A trigger of an arm or activation of a street
traffic light due to weight has not been in practice for many years. It
is highly unlikely that a pressure pad sensitive to weight is ever
controlling a parking lot arm today.
UL 325/ASTM F2200
are several standards that are used to design and install parking
control/barrier arm devices. In the most basic sense, UL 325
(Underwriters Laboratories) in conjunction with ASTM F2200 (American
Society of Testing Materials) as well as other trade organizations have
compiled standards that are designed to make a control/barrier arm
installation safe and user friendly. Most of the regulations that are
referenced in these standards have been adopted and in common trade
practice and usage since the year 2000. There are numerous revisions of
these standards, and industry best practices for service providers and
installers should be to bring any of these past installed products up to
date with the latest revision of the standards for entrapment and
A UL 325 COMPLIANT INSTALLATION
UL 325 compliant barrier arm or parking control arm installation
requires several conditions to be met. The mechanism is generally
installed atop a concrete island (not a UL requirement). All conduits
and control circuits are routed into the base of the barrier arm
mechanism through this elevated platform. This is not always the
observed situation; however, it seems to be the most encountered
condition as the elevated platform provides protection from vehicle
impact for the arm housing. When this island is placed by a concrete
contractor, it is the perfect time for the facility to install a
dedicated pedestrian walkway.
This dedicated pedestrian walkway
must be away from the “danger zone” of the active control arm. This
dedicated pathway is one of the most important factors to having a UL
325 compliant installation. Another significant safety device required
for a UL 325 compliant installation is blatant painted warnings on the
pavement located adjacent to both sides (ingress and egress) of the
control arm. For instance: “Not a Pedestrian Walkway” or “Motor Vehicles
Only” along with bright stripes and designs to draw the attention of a
pedestrian to indicate danger prior to coming into the “danger zone”.
Signage is also required, on the arm itself, the cabinet that houses the
activation equipment, and on a placard in front of the control arm
PEDESTRIAN SIGNAGE, NOT ALWAYS EFFECTIVE
have observed for many years that pedestrians are often walking while
distracted by their cell phones, other people they are engaged in
conversation with, or low lighting conditions. Although a UL requirement
for a compliant installation is having a warning sign placed in several
areas adjacent to and attached to the control arm, that warning is
often unseen for many reasons. Pedestrians often look to the location
that they are planning to reach without seeing their immediate
surroundings. When this occurs, any warning signage has no value to
them. A sign that is attached to a vertically elevated arm is out of the
field of view for a pedestrian in most cases so that warning label is
ineffective. A distracted pedestrian is as likely to walk off a curb in
front of oncoming traffic or walk under a raised parking control arm
without realizing that the danger exists. Blatant pavement signage has
also been ignored by distracted pedestrians focused on getting to where
they want to go.
WHO IS AT FAULT?
a variety of cases where a parking lot barrier arm has malfunctioned
due to a complete lack of maintenance awareness. Most manufacturers
suggest they should be inspected and evaluated for function by a
professional service provider at least once a year. This interval
inspection routine is questionable in a parking area with high usage of
the control arm. In a case of continual usage, a professional service
provider should be in place to inspect the device every quarter.
Usually, some malfunction occurs that requires professional visits more
frequently than every 3 or 4 months in a high usage installation.
property management or an owner employs a maintenance person to make
repairs. This can be problematic, as that maintenance person may not
have adequate skills or training as to how to properly inspect the
functions of the control arm mechanism and related systems correctly. In
other low usage areas, where the arm is either occasionally used,
unused and left in an open condition, or there is minimal parking lot
activity, property owners never get them serviced. They are unaware of
the need for service, feel that the arm is operating correctly when it
is used, or just do not want to expense the services of a professional
due to budgetary constraints or an ignorance of how the device
Most owners of parking control lot arms do not
understand or have the skills to properly check all functions of the arm
control mechanism. They may be capable of replacing a broken arm
component when damaged by a vehicle, but rarely understand the actual
electronic requirements. When a competent, qualified professional
service provider is used to make proactive inspections of a parking
control arm, there are numerous tests and electronic evaluations that
are made with dedicated service equipment that the average equipment
owner would not possess.
One of the most basic critical
evaluations to ensure that a parking control arm is properly functioning
involves checking the resistance capacity of the in-ground magnetic
flux loops. These loops are one of the primary controls for avoiding
vehicular/arm impact collisions. There is an electronic meter known as a
“megohm meter” or “meggar” that checks the condition of the in-ground
loop insulation material of all system loops. It measures millions of
ohms of resistance by placing a signal onto the flux loop when tested.
The unbroken condition of the insulation that is the outside coating of
these in ground wires is essential to have a properly functioning flux
Electrical leakage to the surrounding ground due to partial
loss of the protective insulation creates false imaging to the controls
of the parking arm equipment. The insulation of these flux wire loops
has an expected life. This is due to corrosive aspects of the material
that the wires are encased in. Concrete, asphalt, various cement, sands
and gravel all have corrosive components to their chemical composition.
These acids can affect the lifetime of the flux wire insulation.
Depending upon how much water leaches through the pavement, these flux
wires will eventually be exposed to chemicals that will break down the
insulation protection that is required. When that insulation breakdown
finally happens, the operation of the magnetic flux loop is inconsistent
and often becomes a danger to vehicles of all kinds (cars, trucks,
motorcycles, bicycles, trailers, etc.) using the control arm.
operation of parking lot control systems has been frequently observed
following flooding due to driven rains or adjacent sprinkler systems. In
several past cases, service providers and owners that failed to take
critical tests to determine insulation quality of magnetic loops have
been responsible for damage caused as a result of those unknown wire
conditions. In some claims, the service provider was aware that the
loops were not functioning up to specifications of the loop manufacturer
yet failed to take any proactive action to have them replaced, or
minimally alert the owner of the arm that the condition existed. To save
money, some service providers fabricate their own loops for these
installations. When that is the case, the service provider needs to
regularly verify the condition of the loops to make certain that the
performance is as required.
ADDING ADDITIONAL SAFETY FEATURES
is usually a goal to make a product that is as safe as is possible for
all users. The UL 325 standards attempt to keep current with
technological advances but are not always up to date. Basic requirements
as described above do make control arms reasonably safe, but there are
additional safety devices that can be added to most parking control
Cross threshold optical sensor beams. These beams
function in the same way that a common residential automatic garage door
bottom beam sensor works. They provide an additional protection to both
vehicles and pedestrians as they stop the control arm from descending
when the beam is obstructed. To be effective, they need to be properly
positioned and in enough quantity.
Audible alarms are being installed to alert pedestrians and drivers in proximity to the control arm that it is about to descend.
Visible alarms that provide strobe or flashing light action alert pedestrians and drivers that the barrier arm is about to descend.
Contact safety switches attached to the bottom edge of a
parking control arm cause the descending arm to reverse when 10 pounds
of force from an obstruction occurs.
These added safety devices are not part of any standard requirement but
are relatively inexpensive to add to a control arm system and tend to be
more effective in warning pedestrians that something is about to
happen. Both alarms begin working a few seconds before any activation
movement of the arm starts. A properly positioned beam or beams can be
effective in stopping the descent of a control arm when a pedestrian is
obstructing the beam but is not fully reliable due to user interactions.
It is best practice to avoid having any pedestrian walk under the
pathway of a control arm.
THE IMPORTANCE OF KNOWING THE ACTIVE CONDITION OF ALL MAGNETIC LOOPS
motorcycle injuries from parking arms have occurred as a direct result
of magnetic loop degeneration. Properly operating control loops should
have enough sensitivity to “notice” most metallic objects. I have been
able to test magnetic fields for gates and control arms using a one-foot
square piece of sheet steel with positive results that have activated
the devices. Cars and trucks obviously have larger footprints than a
motorcycle, scooter or bicycle, but if the loops are sensitive enough
and the module that controls those loops is properly adjusted, it is not
unreasonable to get a big enough change in the magnetic field to
trigger the operator mechanism. Unless there are specific access and
egress points for motorcycles and other two wheeled conveyances, most
riders will expect that a control arm will react to their rides. It is
critically important to have competent professional service providers
evaluate control arm systems on a regular basis. Changes to sensitivity
of the magnetic fields that can occur suddenly create problems resulting
in cosmetic damage to cars but can cause catastrophic dangerous
conditions for two wheeled vehicles. Motorcycle accidents with barrier
arms are particularly dangerous when the safety loops that are
positioned under the control arm fail or work intermittently. A rider
will gain access, the arm will lift, and without warning it will descend
into the face or on top of the head of the rider leading to potentially
severe injuries. It is a reasonable expectation on the part of a
motorcycle operator that the arm will remain open and the in-ground
loops will detect the presence of a motorcycle. Dangerous conditions
that exist as a result of deferred or non-existent maintenance of
parking control arms have created many motorcycle rider impact injury
VARIETY OF OBLIGATIONS ON ALL PARTIES
THE OWNERS OBLIGATIONS
there is no proactive maintenance of any device or piece of equipment
in a facility the owner is negligent for failing to make the effort to
ensure that the property will be safe for all invitees. Failing to
employ competent professional service providers due to cost, ignorance,
laziness or stupidity is negligent. Having properly maintained and
properly operating equipment is responsible and meets the standard of
care expected of an owner that invites the public on to the property.
Having a proactive plan to provide inspections and maintenance of all
equipment is responsible and diligent. If the professional service
provider has not met the standard of care, the owner may ultimately have
the responsibility for the defective condition of the control arm.
Whether or not there is an indemnification policy between the service
provider and owner can determine who is financially responsible for the
injury claim. If the owner has been informed of operational or
functional deficiencies by others and has refused to upgrade or make the
control arm standard compliant, it is more probable than not that the
owner will become a responsible party.
A SERVICE PROVIDERS OBLIGATIONS
a professional service provider does not make the property owner aware
of changes in standards or advise the owner of possible safety upgrades,
that professional is not acting up to industry expectations. The
service provider is also not taking the opportunity for increased sales
revenues derived from making those suggestions. If a service provider
has offered limited services to an owner (such as an on-call / as-needed
basis), it is hard to place the blame on the service provider that was
just providing specific work. It is still recommended that all
deficiencies in an operating barrier arm system be identified,
specified, and described so that the service provider can transfer the
liability onto the owner of the now non-compliant control arm.
a professional service provider installs a parking control arm in a
non-compliant installation (for example there is no dedicated walkway or
signage), the obligations for that deficiency depend upon the
communication and working relationship with the owner of the property.
There are several different scenarios that determine the responsible
parties for the non-compliant conditions.
Was the service provider only called upon to install a specific product?
Was the service provider limited by the owner of the property to only do a specified job?
Did the service provider make the owner aware of the deficiencies of the
installation prior to, during or after the work was performed?
Did the service provider attempt to make the installation current standard compliant, but was told not to?
What portion of the installation was the service provider involved with?
For example, the service provider was contracted by a general
contractor and told to specifically provide a portion of the products
required to make the installation compliant. The representations made by
the general contractor was that the general would place all signs when
the project was turned over to the owner, the general would have
appropriate pavement warnings painted and placed when the paving was
completed, and the general would install a dedicated walk way for
pedestrians at a later date.
If the service provider acted in a trade appropriate manner, fulfilled
all duties and obligations informing the owner or management of the
non-compliant conditions encountered, that service provider has met the
industry standard of care. In that case, the service provider is not
responsible for a non- compliant control arm installation.
PEDESTRIANS INVOLVED IN A PARKING CONTROL ARM INJURY
WHAT WERE THE CIRCUMSTANCES?
condition has been seen so many times that multiple injuries were
caused in the exact same way. In several past claims, a pedestrian was
essentially forced to walk under a parking control arm because there was
no other way to exit the lot or garage space. There was no dedicated
pedestrian walkway, no openings in a fence, no indicated paths for
people to exit, no special stairways or other means of egress, and in
those cases, the control arm was unavoidable. In other claims, a
remotely operated control arm, that was activated by a guard in an
adjacent hut came down upon several pedestrians due to the guard being
careless. The gate was routinely in an upright position, the guard never
meant to have the gate close upon the pedestrians, yet the injury took
place as a direct result of the guard’s negligence.
ACTUAL CASES OF PEDESTRIANS BEING STRUCK BY PARKING CONTROL ARMS
group of pedestrians walking into a concert venue walked under a
control arm, which came down just as they walked under it. There was
plenty of space on either side of the control arm, but there was no
signage or painted warnings on the pavement showing where the arm could
A pedestrian going to work in a hospital, caused her
own injury. She watched as a car went through the control arm entry
point and did not realize that the gate would close upon her. In her
deposition statements she said she thought that the arm would stay up
because she had seen other people walk through the same opening in the
past without the arm descending. There was a dedicated walkway a few
feet away from where this incident occurred, going through the vehicle
path was a shortcut that saved a few steps and caused her major injury.
of an apartment complex gets hit with control arm gate after helping a
neighbor gain access when the neighbor had forgotten her card key access
pass. The injured party stood adjacent to the control arm, swiped her
access card, watched her friend drive through the opening and then
without thought proceeded into the lot following the car. Once the car
cleared the magnetic loops, the arm descended as designed, only it
struck the tenant, knocking her out only seconds after her good deed.
INTENDED USE OF CONTROL ARMS
arms are designed for restricting the flow of vehicles into or out of a
location that desires regulation of traffic. The equipment functions
based upon activation signals received as described above. Access points
that have control arms are not intended for pedestrian traffic at any
time. While most vehicles are metallic, most pedestrians are
non-metallic. The machines that operate these control arms are dumb
robots without any capabilities of intervention in the event of a non-
conforming use. A pedestrian attempting to walk through a parking
control arm location is a non- conforming use, and there must be some
common sense exercised when assessing an interaction with any robotic
PROPERTY OWNER OR PROPERTY MANAGER RESPONSIBILITIES
owners that have public, commercial, or residential community
properties can expect usage by thousands of different people. If
proactive maintenance and evaluation of the location setting as well as
the condition of the equipment that people interact with is made
routinely, an owner can take the needed steps to keep the property in a
reasonably safe condition. An owner should enlist the services of
qualified and competent service providers to make certain that all
access control arms are properly functioning, and the site is totally
compliant. If an owner takes responsibility and hires professional
service providers to make a property fully compliant, that owner has met
his obligations to all invitees of the property. Failing to proactively
evaluate a potentially dangerous condition is negligent. Maintenance
saves money in the long run. Keeping equipment of all kinds in good
condition is responsible and indicates good ownership. Safety to all
invitees should be of prime importance to a concerned owner.
TERMS YOU SHOULD KNOW
Magnetic induction flux loop:
A wire of specific size and design placed below the pavement surface to
create a magnetic field which is altered when a metal object (vehicle)
is in proximity or on top of the wire field.
A printing device used to dispense parking tickets to patrons of a
parking lot. Manual (push button by user) or automatic (triggered by
presence of vehicle on top of magnetic loop in ground), records date and
time of entry onto a paper ticket and then when removed from the slot
activates a control arm mechanism to gain access into the lot.
Control arm device: All electronic and mechanical equipment combined to allow a gate arm to raise and lower.
Approach loop: Magnetic loop placed in ground to trigger activation of a control device.
Magnetic loop placed directly under the path of a parking control arm
to protect vehicles from impact by a descending gate arm when the zone
is occupied by a vehicle.
Egress loop: Magnetic
loop placed in ground to hold a control device in the open position
until the area can be cleared. Usually in place in high traffic or cross
Megohm meter (Megger): An
electronic meter designed to determine resistance in millions of ohms,
relevant to this article, checking for leakage due to the breaking down
of insulation on in ground magnetic flux loop wires used to control
parking control arm actions.
Zone of Danger: The
area immediately under the path of a descending parking control arm and
any immediate area where a pedestrian could be struck by a descending
arm without notice.