Why does the light take so long to change?
Why is every light red? Can't they coordinate them?
There is not enough pedestrian time to cross the street! The pedestrian signal does not work.
There should be a delay before the light changes to the next movement; too many people run the red lights.
The signal cycles even when no vehicles are present.
The light is too short, it needs more time!
Traffic is backed up exiting my neighborhood; can we get the signal retimed?
Who do I call if a signal is malfunctioning?
I was in a crash and there are cameras at the traffic light, Can I get the video recording? How can I get traffic signal reports?
How do we get a traffic light installed?
Why isn’t there a turning arrow at this traffic light? How can one be requested?
Who do I call if a STOP sign is down and/or twisted?
Who do I contact to report street lights out on a major roadway?
Who do I contact to report a residential street light out?
Q # 1 - Why does the light take so long to change?
Delay encountered by motorists or pedestrians waiting on minor approaches to traffic signals is one of the most common complaints from the public received by traffic agencies. Traffic signals operating in a coordinated mode require between two and a half to three minutes to completely cycle. During a traffic light cycle, the green for each traffic movement has one opportunity to occur. If someone approaching the traffic signal has just missed their green light, they will not receive a green until the next cycle of the light which may take up to three minutes before it occurs again.
Within each cycle, a block of time is allocated to each traffic movement. If a traffic movement does not need all of its allocated time, the unused time becomes available to the next traffic movement in the cycle sequence; this continues until all of the unused time, if any remains, ultimately is added to the major or main street movement where it remains until the cycle “zeros” itself out. Cycle lengths vary depending on the time of day. During the AM and PM rush hours, signals employ their longest cycles because the major roads must accommodate the greatest amount of traffic. During the midday in between AM and PM rush hours, the cycle lengths are slightly shorter and the shortest cycles typically occur during overnight hours.
Example: Suppose one is on W. 11 Avenue approaching the signal at Broward Blvd. The signal has just turned red and the cycle length is 160 seconds. The next time the signal can appear would be 160 seconds minus the amount of time it just used for W. 11 Avenue. The delay is less if one approaches while the signal has already been red for some time and it can vary each time up to a maximum of 160 seconds. Even though there may be a period of time where it seems that few or no vehicles pass on Broward Blvd., in reality a group of 50, 75 or 100 cars that have been released from a nearby major intersection are on their way.
Main Street: Each intersection controlled by a traffic signal is assigned a main street and minor street. The main street is the busier or more important of the two intersecting streets to which a traffic signal’s green time is favored.
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Q # 2 - Why is every light red? Can't they coordinate them?
Ideal traffic flow depends on three components: signal timing, roadway capacity, and operations. During periods of heaviest traffic when traffic flow or coordination breaks down, roadway capacity can be up to 60% of the cause, signal timing 20% and operations 20%. Once traffic volumes return to levels below the roadway capacity, signal timing re-emerges as the most important component toward moving traffic as efficiently as possible. Unfortunately, commonly held perception is that signal timing is 100% of both the solution and problem.
Some of the most common reasons that traffic signal coordination breaks down include the following: roadway construction, interconnect damage which cuts off a traffic signal from the central computer, roadway capacity, poor traffic signal spacing, timing, and traffic signal pre-emption.
It is easy to coordinate signals that are on one-way streets to provide for very effective movement of traffic. That is why one-way streets are more common in downtown areas – it is the most efficient way to move large amounts of traffic with relatively few lanes and quickly cycling signals. However, as one gets away from downtown areas, one-way streets are much less prevalent. Coordinating signals on two-way streets where the signals are irregularly spaced is not always possible. In those cases, signal coordination is often set up to favor one direction of travel over the other.
To provide signal coordination, most signals in Broward County are wired or connected to the central computer at the Traffic Engineering Division through some 420 miles of underground cables called interconnect.
The central computer provides coordination instructions to the traffic signals through constant communication. Ideally a stream of green lights occurs along an arterial roadway while traveling at the speed limit. The central computer also allows for longer green lights targeted to specific traffic movements when it is known that traffic is heavier during certain times of the day.
When the communication between traffic signals and the central computer is disrupted, those signals continue to cycle, but they are no longer coordinated and operate completely independent of each other. Communication disruptions usually occur from cuts to the interconnect due to construction activities, noise in the line or by a pre-emption.
Example 1 (Roadway Capacity): Myrna’s normal route to work in the morning is on Pines Boulevard from US 27 to I-75. As she approaches Dykes Road, the traffic on Pines Blvd. comes to a complete stop. There are no traffic crashes and the traffic lights further down the road are all green. Why is traffic stopped?
Answer: The roadway capacity has been exceeded. Once this occurs, traffic can no longer move at a reasonable speed and the traffic signals merely function to meter traffic through the area. Additionally, during these times, the side street demand is also at its greatest thereby using greater amounts of their green time. This can also occurs on freeways such as I-595 where there are no traffic signals.
Example 2 (Cuts): Arturo lives near SR 7 in Lauderdale Lakes and works in downtown Fort Lauderdale near Broward Blvd. and Andrews Ave. His normal route is south on SR 7 from NW 41 Street then east on Broward Blvd. Arturo approaches Oakland Park Blvd. and gets a green light. He then makes it through all of the traffic lights without stopping until he approaches Sunrise Blvd. where a minor construction project off to the side of the road is underway. Once he passes that intersection, he gets stopped at nearly every signal until he reaches Broward and W. 31 Avenue. This never used to occur until recently. What happened to the normal traffic signal coordination?
Answer: The nine traffic signals south of Sunrise Blvd. on SR 7 then eastward on Broward Blvd. have been cut off from the central computer therefore are no longer coordinated. This was caused by a cable cut that occurred during the construction project in the vicinity of SR 7 and Sunrise Blvd.
Example 3 (Noise): Jorgen travels from the Inverrary neighborhood to Dania Beach utilizing Oakland Park Blvd. to I-95 to Stirling Road. His route is east on Oakland Park Blvd. to I-95. Usually, once Jorgen passes through SR 7 on Oakland Park Blvd., he can proceed through all of the signals up to I-95. Today, he gets stopped at NW 27 Avenue just east of SR 7 but this does not occur normally. To further add to the frustration, he gets stopped at NW 21 Ave. and NW 18 Ave. What caused this breakdown in traffic signal coordination?
Answer: The traffic signal at Oakland Park and US 441 has experienced a temporary communication failure due to noise or static in the interconnect line. Since Oakland Park and US 441 is temporarily uncoordinated, the green for Jorgen occurred at the wrong time and he is no longer aligned with the subsequent signals along Oakland Park Blvd. It only takes one uncoordinated traffic signal to cause a motorist to be out of step through several subsequent traffic signals.
Example 4 (Pre-emption): Blanche travels on the Turnpike and exits at Commercial Blvd. The Turnpike exit signal to travel east on Commercial Blvd. is usually timed so that she can proceed on Commercial through SR 7 without stopping. Today she gets stopped at SR 7 and the traffic back up is longer than normal. What happened to the usual signal coordination?
Answer: An emergency vehicle left the nearby fire station a couple minutes earlier and has pre-empted these traffic signals. This has temporarily disrupted the normal synchronization of the traffic signals and takes a few minutes to return to their proper coordination settings.
Roadway Capacity: The maximum number of vehicles that can use a roadway and still travel at the speed limit. This is commonly measured in vehicles per hour (vph). Three lanes of roadway have a capacity of about 2500 vph before traffic can no longer move at the speed limit. It is not uncommon for major roadways in Broward County to exceed this threshold by over 1000 vehicles per hour.
Operations: This refers to a number of roadway components including traffic signals and roadway design. Traffic signal operations include the spacing, responsiveness and sequencing of traffic signals. Roadway operations refer to the layout, spacing and design of medians, left turn lanes and right turn lanes.
Cuts: Interconnect cuts are the worst type of communication failure because they take the most time and money to restore or repair and disrupt all other signals downstream from the cut. Cable cuts can impact as few as one traffic signal to as many as several hundred depending where it occurs.
Noise: Noise in the line usually disrupts communication to one or two signals in an area. Think of a computer connected to the Internet via a modem (on-line). If there is too much static or noise in the telephone line, that modem disconnects or falls off-line and the internet connection is lost temporarily. This type of communication failure is usually corrected within 24 hours. Traffic Engineering generates a report each morning that identifies all of the signals that have fallen off-line and communications experts are dispatched to those signals to restore the communication to the central computer.
Pre-emption: Pre-emption occurs at traffic signals near railroads, fire stations and drawbridges. A pre-emption causes the signal to immediately ignore the central computer, utilize a special cycle sequence, then return to normal operation. Pre-emptions are self- correcting and do not require Traffic Engineering personnel to restore coordination however, during the transitional cycles of the signal immediately afterward, signal coordination is lost for a few minutes afterward.
Emergency vehicles such as fire trucks and paramedics are also equipped with transmitters that can take over traffic signals while on an emergency run. This is facilitated by encrypted GPS technology and only activates while the emergency vehicle approaches a traffic signal.
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Q # 3 - There is not enough pedestrian time to cross the street! The pedestrian signal does not work.
Every pedestrian signal has a WALK followed by a red flashing DON’T WALK. Frequently, people report that a signal does not allow enough time to cross the street on the WALK. Pedestrian signals usually time concurrently with a green vehicular signal therefore won’t cause a traffic signal to change any faster than if a vehicle were waiting for a green light.
The brief WALK signal means to begin crossing the street and watch out for right or left turning motorists (although the pedestrian legally has the right-of-way, many motorists are not watching for pedestrians). A red flashing DON’T WALK means that if one has already begun crossing, continue! The red flashing DON’T WALK will provide enough time to safely complete crossing the street before cross traffic receives a green light. A red flashing DON’T WALK also means if one has not begun to cross the street, wait until the next WALK appears after pushing the pedestrian button.
In order to guarantee adequate crossing time, the pedestrian signal must be activated by pressing the button on the corner. Crossing on a green light, which is intended for vehicles, does not guarantee enough time to cross the street. Green lights on side streets vary in duration and can be brief especially when only one or two vehicles are present.
Modern pedestrian signals countdown the amount of time remaining to cross the street. While they are timed no different than traditional pedestrian signals, they do provide additional information to the pedestrian.
Example: The WALK light does not appear or is too short to cross Federal Highway.
Answer: The pedestrian signal will not appear until the concurrent green appears during the signal cycle provided it was activated. Once it appears, a WALK of at least 5 seconds indicates begin crossing; then the red flashing DON’T WALK occurs. If the pedestrian has begun crossing, complete the crossing. Pedestrian signals stop cross traffic sufficiently long enough to cross the street. NEVER rely on a green light indication for its duration varies and can be insufficient.
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Q # 4 - There should be a delay before the light changes to the next movement; too many people run the red lights.
All traffic signals in Broward County already have a delay. This delay is known as ALL RED which occurs immediately after the yellow. ALL RED simply means the signal is red for all directions of traffic for a couple of moments before the cross traffic gets their green. The amount of ALL RED is based on the speed limit and the distance a vehicle must travel through the intersection.
Casual observers will not notice the ALL RED but it is noticeable if one looks closely. The ALL RED is intended to get a vehicle through the intersection traveling at the speed limit which enters the intersection at the end of yellow.
No amount of ALL RED will prevent every vehicle from running a red light however; the nominal amount of ALL RED used, gets the majority of vehicles through the intersection which do not stop in time by the end of the yellow. The majority of red light running crashes occur within the first two seconds of the onset of red.
If too much ALL RED is applied to a signal, it becomes obvious to motorists and they potentially become inclined to speed up on the yellow or run the red light. Also, if excessive amounts of ALL RED are added to every traffic movement, particularly at large intersections with eight signal movements (four throughs plus four lefts), nearly 30 additional seconds to the traffic signal cycle would be added!
Never assume an intersection is safe just because it has ALL RED. There is always the possibility someone may run a red light at any time particularly with the proliferation of driver distractions such as electronic devices. Always look once the signal turns green before proceeding through the intersection.
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Q # 5 - The signal cycles even when no vehicles are present.
Every signalized intersection has a designated major street or movement, usually the through movement of the major street. All other movements are actuated or “on demand”. In order to have actuation, some sort of vehicle detection is necessary.
In Broward County, the most common forms of vehicle detection are video-based and magnetic induction loop detection.
Video-based detection uses cameras which memorize the view of an approaching roadway and senses changes in that view. This occurs by measuring a change in pixels of that memorized image thus placing a call for a green light to the traffic signal controller. These devices do not record traffic events.
Magnetic induction loop detection is simply a wire loop embedded about half an inch into the pavement of each lane extending back from the stop bar with typical dimensions of 40 X 8 feet. When a vehicle is over the loop, a change in magnetic flux is detected which then places a call for a green light. Businesses with drive throughs and exits at gated communities typically use this type of vehicle detection as well.
Once a green light appears, the signal will stay green as long as it needs to up to a set maximum amount of time (actuated). If only one or two vehicles are present then the green may last for perhaps 6 seconds. If 15 vehicles are present then it may stay green for 30 seconds. If no vehicles are present, the signal will not utilize and skip that movement.
Broward County’s current standard is video-based vehicle detection. Approximately 450 traffic signals now use video-based vehicle detection and up to 700 more will be equipped with video detection in the next two to three years. These new installations are currently underway at a rate of about five traffic signals per week.
Pavement loops are no longer maintained as this is too costly. Their lifespan can range from as little as a couple months to as much as a few years. Unfortunately, asphalt pavement is relatively soft and loops are very fragile so they often fail. When this occurs, the traffic signal is set to cycle to that movement 24 hours a day for a fixed amount of time typically consistent with the amount of green time needed during periods of heaviest traffic. Construction projects that disrupt the pavement also destroy detection loops.
Example 1: James is traveling west on Sample Road, approaches Military Trail as the light just turned red. It is late at night and there is very little traffic. Two cars on Military Trail turn left onto Sample and that light stays green for an additional 15 seconds. Then, eight vehicles total on Military Trail head north or south and that light stays green for an additional 25 seconds as one or two more vehicles pass. After that, the left turn arrows on Sample appear for 20 seconds and no vehicles at all are present. Finally, James gets a green light.
Answer: The loops in the pavement have failed so there is no longer vehicle detection. The signal has been set to cycle a fixed amount of time needed for each movement when traffic is heavy.
Example 2: Laura is traveling east on Commercial Blvd. and stops at Prospect Road. There are four vehicles on Prospect headed south waiting to turn left onto Commercial and no others waiting at the intersection except on Commercial headed east or west. The left turn light for Prospect appears and turns yellow as soon as the last vehicle leaves the turn lane. Then the signal turns green again for east and west traffic on Commercial.
Answer: The intersection is "on demand" or actuated with functioning vehicle detection. Since there were no vehicles headed north or south on Prospect and no vehicles on Commercial Boulevard waiting to turn left, all of those movements were skipped because they were not needed. The signal will can stay green for Commercial until Prospect needs it again whether it be one minute or even ten minutes later.
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Q # 6 - The light is too short, it needs more time!
Usually one of the following three things is occurring;
(1) There is too much traffic,
(2) Someone is not paying attention, or
(3) A traffic signal pre-emption is underway.
Example 1: There is too much traffic: All roadways have a certain capacity (Why is every light red? Can't they coordinate them?) Once this capacity is exceeded, the traffic signal cannot clear each movement as is normally expected. Pines Blvd. and Flamingo Road is one such example. Traffic continuously approaches from all directions at that signal during rush hour. Each movement is given a generous amount of time but it is never enough to clear all of the vehicles in any direction. If any of the movements at that intersection are delayed any longer than they already are, the backup grows exponentially. Another example of overcapacity and its effect is I-95 during rush hour. Frequently traffic only moves at about 40 to 50 mph yet there are no crashes blocking lanes and obviously no traffic lights. As massive as that road is, it simply has more vehicles on it than it can handle. Overcapacity is usually a temporary condition but when it is chronic, expansion of the roadway should be considered.
Example 2: Someone is not paying attention. Chris is in the fifth vehicle in line waiting to turn left from Oakland Park Blvd. onto Bayview Drive. Normally, the green arrow has enough time to clear up to 12 vehicles but this time the driver of the vehicle in front of her sped up after initially not realizing the light was green and made it through the yellow leaving Chris stuck until the next light.
Answer: The driver of the last vehicle that made it through the light was not paying attention causing too much time to elapse between vehicles passing over the detection zone. The signal sensed no more vehicles so it turned yellow.
Example 3: Xavier is northbound on I-95 and exits at Commercial Blvd. Five seconds after the light turns green it suddenly turns yellow when normally; the light is green much longer due to a high number of vehicles waiting to get off of I-95.
Answer: Just to the west of that interchange is a railroad track not visible from the off ramp. Whenever a train passes, the signal is pre-empted and immediately follows a special sequence designed to clear the railroad tracks of vehicles. Once the train passes, the signal returns to its normal sequence and the northbound off ramp will then get its normal amount of green time.
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Q # 7 - Traffic is backed up exiting my neighborhood; can we get the signal retimed?
There is a difference between back up and clearing traffic. Back up will typically clear out once the signal is green. This should not be confused with poor traffic signal timing. Traffic engineers are primarily concerned with maximizing traffic signal synchronization on the major roadway since the majority of vehicles are on the major roadway that requires traffic signal coordination therefore receive the majority of the green time. See: Why does the light take so long to change?
As long as there is sufficient green time provided to minor approaches to clear the waiting traffic, the backup condition is considered acceptable – these motorists are secondary roadway users until they enter a major roadway. Additionally, once that minor street green appears, its duration is completely dependent on the reaction and behavior of the motorists since the green relies on vehicle sensors. Any delay by an inattentive motorist will rob subsequent motorists of their green light. See: The light is too short, it needs more time! Example 2.
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Q # 8 - Who do I call if a signal is malfunctioning?
Monday through Friday, between 7:00 a.m. and 5:00 p.m. call (954) 847-2600 to report the location, direction and type of problem. After 5:00 p.m. weekdays, weekends and holidays, call (954) 847-2600, press 5 and the pound (#) sign and you will be connected to our Central Dispatcher.
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Q # 9 - I was in a crash and there are cameras at the traffic light, Can I get the video recording? How can I get traffic signal reports?
Traffic is not visually recorded by the Traffic Engineering Division. The Division is not an enforcement or crash reconstruction agency, other experts and police departments perform those functions.
Information regarding the sequencing and maintenance of traffic signals however is available to the public. This may be obtained in writing to the Division through a public records request. The request may be submitted via fax or US mail to the attention of the Records Custodian:
US Mail: Broward County Traffic Engineering
2300 W. Commercial Boulevard
Fort Lauderdale, Florida 33309
Please include the location, date(s), approximate time of day and reply contact. The turnover time may be up to two weeks and there may be a charge for large requests.
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Q # 10 - How do we get a traffic light installed?
Traffic signal installation is typically a last resort in traffic control and has a high threshold prior to installation. Foremost is meeting warrants established by federal standards as outlined in the Manual On Traffic Control Devices (MUTCD). Warrants include measures such as side street delays, number of correctable crashes and a general increase in traffic volume. Since the potential for a crash exists at any intersection, an acceptable number of correctable crashes is typically about three per year or five in two years as it is impractical to install a traffic signal at every intersection.
New traffic signals are expensive. A modern steel structure traffic signal costs up to $300,000 and requires perpetual maintenance and electricity costs of about $2500 per year.
Despite this high threshold, it is not impossible to get a traffic signal installed and the Traffic Engineering does perform traffic signal warrant studies on County and local intersections. Warrant studies on intersections that are part of the state roadway system are performed by the Florida Department of Transportation (FDOT).
Requesting a traffic signal warrant study on a County or local intersection is easy; simply contact the Traffic Engineering Division, a County Commissioner, City Commissioner or mayor. Circulating petitions or demanding a traffic signal from your local legislator does not increase or decrease the likelihood of getting a traffic signal installed since the warrant study is the means through which the decision is made.
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Q # 11 - Why isn’t there a turning arrow at this traffic light? How can one be requested?
Turning arrows at existing traffic signals are installed on an approach by approach basis and need to meet certain warrants or thresholds before they are installed. These warrants typically involve counting vehicles during several hours and once the product of the number of left turning traffic versus the opposing through traffic exceeds a certain number, the turn arrow is installed. This product needs to exist for several consecutive hours during a typical day. Many traffic signals actually surpass the threshold but that condition may only last for about half an hour during rush hour. In these instances, a turn signal is not installed since the condition is temporary on a daily basis.
An unusually high number of crashes may also warrant a turn arrow however, other factors are investigated before the decision is made to install a turn arrow. These include, but are not limited to, sight obstructions, crash analyses and the circumstances surrounding those crashes.
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Q # 12 - Who do I call if a STOP sign is down and/or twisted?
Monday through Friday, between 7:00 a.m. and 5:00 p.m. call (954) 847-2600 to report the location and direction of the problem. After 5:00 p.m. weekdays, on weekends and holidays, call (954) 847-2600, press 5 and the pound (#) sign and you will be connected to our Central Dispatcher.
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Q # 13 - Who do I contact to report street lights out on a major roadway?
Monday through Thursday, between 7:00 a.m. and 5:00 p.m. call (954) 847-2713. Leave your name and phone number and location of problem. Your call will be returned to confirm the information.
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Q # 14 - Who do I contact to report a residential street light out?
For residential street lights contact Florida Power and Light Company at (954) 797-5900.
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