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Transportation & Public Works - Traffic Engineering

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1. How do I get a traffic signal installed?

Traffic signals assign the right-of-way to various traffic movements within an intersection. Before installing a traffic signal at an intersection, established minimum warrants must be satisfied. Athens-Clarke County complies to the warrants set by The Manual on Uniform Traffic Control Devices (MUTCD), which is published by The Federal Highway Administration (FHWA). Traffic and pedestrian volumes, accident history, and/or unusual conditions must be satisfied or present at the intersection before a traffic signal may be considered. Once the signal is under consideration the installation must first be approved by The Mayor and Commission and funding be in place.

Unwarranted or inappropriately placed signals can:

* Increase overall travel times by adding stops and delay for through traffic.
* Cause the diversion of traffic onto residential streets to avoid the signal.
* Cause a significant increase in rear-end collisions.
The Manual on Uniform Traffic Control Devices (MUT

2. Will a traffic signal reduce crashes at our intersection?

Traffic signals don't always prevent crashes. In many instances, the total number of crashes and injuries increase after they're installed.
Where signals are used unnecessarily, the most common results are a reduction in right-angle collisions but an increase in total crashes, especially the rear-end type collision. In addition, pedestrians are often lulled into a false sense of security.
In deciding whether a traffic signal will benefit a particular location the following criteria will be evaluated:

• Does the number of vehicles on intersecting streets create confusion or congestion?
• Is main street traffic so heavy that drivers on the side street will try to cross unsafely?
• Are there enough pedestrians trying to cross a busy main street to create a hazard?
• Does the number of school children crossing a street require special controls for their protection?
• Will a signal allow for continuous, uniform traffic flow with a minimum number of vehicle stops?
• Does an intersection's crash history indicate that a signal will reduce the possibility of a collision?

Our staff will compare the existing conditions against nationally accepted minimum standards established by The Manual on Uniform Traffic Control Devices (MUTCD) - Section 4C. At intersections where standards have been met, the signals generally operate effectively with good public compliance. Where not met, compliance is generally reduced resulting in additional hazards.
While a properly placed traffic signal improves the flow and decreases crashes, an unnecessary one can be a source of danger and annoyance to all who use an intersection: pedestrians, cyclists and drivers.

The Manual on Uniform Traffic Control Devices

3. How do I get a stop sign installed? (Includes additional signs at existing 2-way stops)

Stop signs assign the right-of-way to various traffic movements within an intersection. Before installing a new stop sign at an intersection or converting a two-way stop into a multi-way stop, established minimum warrants must be satisfied. Athens-Clarke County complies to the warrants set by The Manual on Uniform Traffic Control Devices (MUTCD), which is published by The Federal Highway Administration (FHWA). Traffic and pedestrian volumes, accident history, and/or unusual conditions must be satisfied or present at the intersection before a stop sign may be considered. Once the stop sign is under consideration the installation must first be approved by The Mayor and Commission and funding be in place.

Unwarranted or inappropriately placed stop signs can:

* Increase traffic delay, speed and congestion with little or no gain in safety. In fact, safety is sometimes reduced.
* Frustrate and anger motorists, who may divert to less suitable streets.
* Reduce the credibility of stop signs and cause them to be ignored.

Although the physical installation of a stop sign is relatively inexpensive, studies have shown that there are "associated" costs involved which must also be considered:

* The sign must be maintained after installation.
* Extra fuel is consumed when vehicles stop and then re-accelerate - 24 hours per day.
* Extra fuel consumption also leads to increased air pollution. Stopping 5,000 vehicles
per day generates 15 tons of additional pollutants per year.

A common reason for requesting an all-way stop is to encourage speeding drivers to slow down. It is important to note that Section 2B.04, Paragraph 05 of the MUTCD states: “YIELD or STOP signs should not be used for speed control.” Installation of an all-way stop intersection solely to slow traffic would constitute a violation of 23 Code of Federal Regulations (CFR), Part 655, Subpart F and will not be considered. The FHWA based this decision on a large volume of research, some of which is available online, which indicates that:

• All-way stops do not control speeds except under very narrow conditions, and
• Drivers learn to ignore unwarranted stop signs risking similar behavior at other intersections.
The Manual on Uniform Traffic Control Devices (MUT

4. Why do I have to wait so long at a traffic signal?

The reason is that many of the arterials in Athens-Clarke County are time coordinated. The goal of coordination is to get the greatest number of vehicles through the system with the fewest stops in a comfortable manner. Therefore, in traffic signal coordination the busiest traffic movements are given precedence over the smaller traffic movements. Once you have entered into the coordinated arterial you should notice more free flowing traffic and a reduction in delay. If you are waiting for a green light to cross the "coordinated" street where there is heavy traffic, you will probably feel like you are waiting for a very long time. In reality, most of ACC's traffic signals require a driver to wait less than 120 seconds and no more than 160 seconds. If you experience unusual timing at an intersection or have questions regarding the particular timing at an intersection, please contact Traffic Engineering at (706) 613-3460 or use one of the links to contact us by e-mail.

5. So how does Athens-Clarke County time its traffic signals?

The objective of traffic signal timing is to alternate the right-of way between traffic in such a manner as to minimize average delay to all traffic while ensuring a safe operation.

The majority of traffic signals in ACC are designed to be either traffic responsive or part of a traffic signal system. Traffic responsive traffic signals are designed to adjust their patterns based on traffic demand. These systems work well, but are limited to locations where we can communicate with the traffic signals from our office. Typically, ACCTE will use traffic counts that have been taken at the intersection to model the traffic signal operation and determine the preset maximum time. Timing for traffic signals that are part of a traffic signal system is typically designed to progress groups of vehicles along a corridor. The department uses traffic modeling software along with traffic counts to determine appropriate traffic signal timings to progress these groups of vehicles along a corridor. Once timing has been programmed for the traffic signal, we will observe traffic flow and further adjust the traffic signal timing to accommodate site-specific issues as needed.

6. How do I report a missing or damaged street sign?

Call Traffic Engineering for the replacement of downed or missing signs. Provide information on the location of the sign, including the street block or intersection, side of street, color of sign and what the sign says. 

During daytime work hours M-F (6:00 AM - 4:30 PM), call (706) 613-3460. For after hours, weekends, and holidays, call the Athens-Clarke County Police dispatch (706)-546-5900.

7. How can I get my curb painted yellow?

Traffic Engineering has the authority to paint 10 feet on either side of a home owner’s driveway, 50 feet at an intersection, or 20 feet at a fire hydrant. Traffic Engineering will repaint existing yellowed curb by request if an ordinance exists. All others will need to be made through a formal request.

8. What about installing Children at Play signs?

Athens-Clarke County does not install these signs. Nationwide studies have shown no evidence that these signs help reduce the number of pedestrian accidents or lower travel speeds. Furthermore, Federal standards do not support these signs because the signs are suggesting that it is acceptable behavior for children to play in the streets. The Federal Highway Administration has revised the Manual of Uniform Traffic Control Devices to no longer include "Children at Play" signs which makes installation of such signs a violation of 23 Code of Federal Regulations (CFR), Part 655, Subpart F.

Manual of Uniform Traffic Control Devices

9. Wouldn't additional speed limit signs help to slow traffic?

Speed limit signs alone don’t necessarily slow traffic. In Athens-Clarke County, the speed limit on residential streets is 25 mph and 30 mph on arterial streets unless otherwise posted.

10. Who maintains traffic signals in Athens Clarke County?

Athens Clarke County Traffic Engineering maintains all traffic signals located within the county, including UGA campus signals and state route signals.

11. Who maintains Flashing School Zone Lights?

The school zone flashers are maintained by Athens Clarke County Traffic Engineering. Traffic Engineering confirms the beginning/ending times for each location from the Athens Clarke County school system. Athens Clarke County Police Department enforces the speed within the zones. Please report any malfunction problems to Traffic Engineering at 706-613-3460.

12. How do signals for pedestrians work?

When a pedestrian pushes the button on the pole, a message is sent from the button to the computer that controls the traffic signal (the “controller”). The controller will see this request for a Walk light, and at the appropriate time, a Walk light will be provided. The button is like a light switch—after you have pushed it once, it is “on” and stays on until the Walk light appears. The standard time the Walk light is displayed is 5 to 7 seconds. When the Walk light comes up, you should begin to cross. Once the initial “Walk” time has passed, the “Flashing Don’t Walk” will appear—the flashing orange hand. This means that if you have not started to cross the road yet, you should not step off the curb. HOWEVER, if you are already in the process of crossing the road, the average pedestrian WILL have enough time to cross the entire road safely. Once the Flashing Don’t Walk time has passed, a solid “Don’t Walk” light will appear—the solid orange hand. Most intersections in Athens Clarke County are equipped with “countdown” pedestrian heads, which display for pedestrians the exact number of seconds remaining before the pedestrian needs to be clear of the intersection.

13. Is it possible for two conflicting directions of traffic at a signalized intersection to receive green lights at the same time?

It is actually not possible for two conflicting movements of traffic to have green and/or yellow lights at the same time. There are a number of safety features that prevent this exact condition from occurring. Even if these features were to fail and the controller of the intersection were to try to have conflicting movements green at the same time, there is another piece of equipment called a “conflict monitor” that is designed specifically to detect and prevent this from occurring. If the conflict monitor “sees” a potential conflict, it puts the entire intersection into flashing operation, and the intersection will stay that way until a technician has been able to fix the problem.
As everyone knows, a yellow light appears after a green light. When a particular movement goes from yellow to red, the entire intersection remains red for a selected amount of time before the next movement receives a green light. This also allows any vehicles that entered the intersection on a yellow (not red) light to safely clear the intersection before the next vehicles receive a green light to proceed. We appreciate any reports of damaged traffic signal equipment, since it is impossible to actively monitor each signalized intersection on a continuous basis. If you do know of any traffic signal indications that may be rotated or not showing an indication (LED burn out), please call Traffic Engineering at 706-613-3460.

14. What happens to Athens Clarke County traffic signals when they lose power?

It depends. Typically the signal will go “dark”. However, some of our existing traffic signals have a battery back-up system (Uninterruptible Power Supply – UPS) that can maintain either normal or flash operation of the traffic signal. Typically the UPS is capable of maintaining power for only a few hours. It is still crucial to remember that if the traffic signals do go “dark”, Georgia State Law §40-6-70 dictates that motorists shall treat the intersection as an all-way stop sign, unless an officer is directing traffic.

15. Why does a traffic signal change for no reason when vehicles are not present?

These signals are on a “fixed time” cycle (downtown signals for example). Another reason may be the vehicle detection on the main street or side street is malfunctioning so each phase of the signal is given time in the signal cycle.

16. What are the cameras at traffic signals for?

Vehicle Detection Cameras– These cameras use video detection technology to detect when a vehicle is approaching a signalized intersection. These cameras are typically mounted on each approach to a signalized intersection and take the place of inductive “loops”.

Inductive “loops”- Are installed to detect vehicles approaching a signalized intersection. A” loop” is wire that is installed in a two inch deep slot that is cut into the asphalt in a rectangle shape which is 6 feet wide by 20 -30 feet long. This “loop” is placed just behind the white line referred to as a “stop bar”. When a vehicle is on top of the “loop” the traffic signal controller will see a change of electrical inductance due to the metal content of the vehicle. If a vehicle comes to a stop past the “stop bar” the traffic signal controller will “NOT” see the presence of a vehicle and the traffic signal will not change. Drivers should always place their vehicle just behind the “stop bar” for proper traffic signal operation.

Please report malfunctioning traffic signals to Traffic Engineering at 706-613-3460.

Answers to Common Questions about these cameras:

• The video on these cameras is not recorded.
• These cameras are not used for photo-enforcement of red-light running.
• Video detection cameras will detect bicycles when stopped behind the STOPBAR (large white stripe located in each lane at every intersection for vehicle stop placement).

17. How much does a traffic signal cost?

Depending on geometrics and the type of signal designed, a traffic signal can cost $130,000 to $250,000.

18. How do I report a damaged or malfunctioning traffic signal?

During daytime work hours - M-F (6:00 AM - 4:30 PM), report a damaged or malfunctioning traffic signal to the Traffic Engineering Office (706) 613-3460.

After hours, weekends, and holidays, report the signal to Athens-Clarke County Police dispatch (706) 546-5900.

PLEASE NOTE: in the event a traffic signal is not operating correctly, the intersection should be treated as a 4-way stop.