| Traffic Signal Cameras |
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| This page last updated July 29, 2023 |
Over
the past couple of decades, cameras at traffic signals have become
ubiquitous. During the same period, red-light enforcement cameras
have been installed in many locations, and there has been much
publicity about them. As
a result, many people believe that all the cameras they see at
traffic signals are enforcement cameras. However, this is usually not
the
case. Below are pictures of the various cameras you'll see at traffic
signals, an explanation of their purpose, and a discussion of red-light cameras in Texas.
Traffic
detection camera
This
is the most common camera type in use at intersections nowadays, and
the one most people (including the media) often observe and mistake for
a
red-light camera. This
camera, however, is actually a video image vehicle detection system
(VIVDS). These cameras are used by the
traffic signal controller computer to determine the presence of
vehicles so that it can change the signals accordingly. This function
used to be performed by inductive loop detectors in the pavement.
However, the cameras are more cost-effective and flexible than
loop detectors. Loop detectors are fairly expensive to install and
reconfigure, have a somewhat high failure rate, and have limited
capabilities compared to video recognition.
 The
way these cameras work is fairly simple. The camera is mounted so that
it has a view of the approach road that it will be monitoring.
Once in place, an engineer at the system console draws "detection
zones" within the view range of the camera of the areas that need to
watched for traffic. (If you've ever configured home security camera
detection zones, this is essentially the same thing.)
The computer then
monitors those zones and
when it detects a significant change in the image of that area
(indicating the presence of a vehicle), it notifies the signal
controller. The signal controller then uses that data to make the
necessary decisions for changing the signals or timings.
VIVDS
cameras are also used to monitor traffic levels and perform traffic
counts on freeways and on arterial roads. And, in many cases, these
cameras can also be accessed remotely by engineers to see what's going
on at an intersection if an issue is reported or detected.
Although
these cameras are
not red-light enforcement cameras per se, VIVDS cameras are often used
in red-light
camera installations as the mechanism to detect when vehicles have
entered the intersection. They may be dedicated to that purpose (i.e.
separate from the signal controller cameras) or they may
serve both purposes. However, it's important to remember that the
presence of these cameras in most cases does not mean the
intersection has photographic red-light enforcement; see the
"red-light enforcement cameras" section below to see what those cameras
look like.
One
drawback of VIVDS
cameras is that they are often not effective during periods of
inclement weather, so in
many cases, they are now being replaced with acoustic, microwave,
infrared, radar, and ultrasonic detectors. These look like small white
panels or boxes mounted on the signal poles.
Signal preemption receiver
This is not even a camera, but rather an infrared
receiver. These are part of a traffic signal preemption system, usually
for emergency vehicles, but also sometimes for public transportation
vehicles. These systems allow an authorized vehicle to change the
signal to green as it approaches the intersection. The emergency or
transit vehicle has a
forward-facing mobile infrared transmitter (MIRT). When activated, the
transmitter sends out a pulsed infrared signal. As it
approaches within about 2,000 feet of a preemption equipped
intersection, the device you see pictured above detects the infrared
signal and notifies the signal controller. The controller then
initiates a preemptive stop phase for all directions except the one
from which the preemption vehicle is approaching. It then changes the
signals to green for the approaching emergency or transit
vehicle to clear any traffic queues and give that vehicle full
right-of-way. It holds the signals green until the vehicle clears the
intersection, at which point the signals return to normal operation.
In
many places, these are being retired and replaced with GPS-based
preemption systems. In those systems, the authorized vehicles send
their current location to a centralized computer constantly, which then
notifies the signals along their route to change as they
approach.
Red-light enforcement cameras
These
are actual red-light enforcement cameras. The assembly at the
far left is a
typical modern red-light camera, while the green boxy one is
an
older style but still in use in some places.
These cameras sit a short
distance before the intersection on the approach road, facing toward
the intersection. An inductive loop detector or a VIVDS camera monitors
the area just beyond the stop line. When the signal turns red, the
detector is activated. When it detects a vehicle passing the stop line,
it signals the red-light camera, which then takes two or more pictures
of the vehicle, usually with a telltale camera flash. The lens is
focused on the violation area so that a clear view of the vehicle, its
license plate, and the signal is visible. Additionally, the controller
timestamps the image and records other pertinent details, such as
location, direction of travel, and length of time the signal was red.
Many cameras now also collect a short amount of video in
conjunction
with the still frame photos to help validate violations.
Images and recordings are then retrieved by or transmitted to the law
enforcement agency with jurisdiction over that
intersection or their contractor for review. In cases where the photos
and/or video clearly
show a violation, a citation is sent to the registered
owner of the vehicle. Photos of non-violations or of situations that
are less definitive are discarded.
In Texas and many other places, a sign similar to the one shown here is
required to be
placed on the approach to an intersection with red-light
enforcement cameras.
Status of red-light
cameras in Texas
Red-light enforcement cameras started coming into use in Texas around
2003, and a law that clarified their use was passed in 2007. That 2007
law required an engineering study before installing such cameras, and
required the installation of signs warning of photo enforcement.
After many years of push back, the Legislature
passed a law in 2019 that banned enforcement cameras, and nearly all
cities in Texas scrapped their red-light camera programs as a
result. But the law grandfathered cities with
existing contracts, allowing them to continue their use until the
contract
expires. By the end of 2019, only four cities still had them: Amarillo,
Balcones Heights, Humble, and Leon Valley. Amarillo's program ended in
August of 2022. Humble and Balcones Heights are scheduled to
end in 2024. Leon Valley, however has a contract through 2039, but
local leaders there are looking for ways to possibly terminate their
contract before then.
There is a lot of misinformation about what can happen if you get
a ticket in one of the remaining places with the cameras,so I'll
summarize what was and is now allowed under the law.
Before the 2019 law, red-light camera tickets were civil violations,
much like many parking tickets. You could never be arrested
for not paying it, and it would not go on your driving record. However,
it could go to a collection agency, and your vehicle registration could
be denied.
But the Legislature has done away with all of that. The 2007
law prevented reporting of unpaid red-light cameras to credit bureaus.
And the 2019 law prohibits the Texas DMV and county tax offices from
refusing to register any vehicles that have outstanding red-light camera
violations.
So to summarize:
- A
warrant cannot be issued and you cannot be arrested for not paying a
red-light camera ticket.
- Failure
to pay a red-light camera ticket cannot be reported to a credit bureau.
- Your
vehicle registration cannot be denied for an unpaid red-light camera
ticket.
- You
cannot be sued for not paying.
So, it appears there are no legal or financial repercussions if you don't pay these
tickets. But, if you want to avoid the hassle of getting violation
letters, or if you just feel a moral obligation to pay, then that's up
to you.
A
link to the 2019 bill that outlawed red-light cameras is in the "Other
sites of interest" section below, along with a report from the
Legislative Budget Board in 2013 giving the status of red-light camera
laws and operations in Texas at that time.
Other
sites of interest
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