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Traffic (Engineering Services)

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1. Why do I have to wait so long for a green light on a side street?

In order to have coordinated traffic signals, each traffic signal in the group must be able to allow the green light for all movements during a common fixed time period. The time period chosen is usually determined by the largest intersection with the most different movements. This will most often be an intersection that has protected left turn arrows for all directions and wide cross streets. For that reason, the time period that is fixed for each traffic signal (the cycle length) may be rather long.

So, if you are waiting for a green light to cross the coordinated street where there are protected left-turn arrows and there is very light traffic on the side street, chances are good that you will feel like you are waiting for a long time, even though you should rarely have to wait any longer than about two minutes.

2. How do I report a problem with a traffic signal, lane markings, or traffic signs?

If you see a problem with traffic signals or missing stop signs, please call (904) 491-7330.

3. What should a driver do when approaching an intersection in which the traffic signal is not working?

This question is answered by Florida Statute 316.1235, Vehicle approaching intersection in which traffic lights are inoperative.

The driver of a vehicle approaching an intersection in which the traffic lights are inoperative shall stop in the manner indicated in s. 316.123(2) for approaching a stop intersection. In the event that only some of the traffic lights within an intersection are inoperative, the driver of a vehicle approaching an inoperative light shall stop in the above-prescribed manner. A violation of this section is a non-criminal traffic infraction, punishable as a moving violation as provided in Chapter 318. (Chgd by L. 1999 ch. 248 (120). Eff. 6/8/99)

4. How is the placement of traffic signals determined?

Traffic signals don't always prevent accidents. In some instances, total accidents and severe injuries increased after signals were installed. Usually, in such instances, right-angle collisions were reduced by the traffic signals, but the total number of collisions, especially the rear-end type, increased.

There are times when the installation of signals result in an increase in pedestrian accidents. Many pedestrians feel secure with a painted crosswalk and a red light between them and an approaching vehicle. The motorist, on the other hand, is not always so quick to recognize these barriers.

When can a traffic signal be an asset instead of a liability to safety? In order to answer this, traffic engineers have to ask and answer a series of questions:

• Are there so many cars on both streets that signal controls are necessary to clear up the confusion or relieve the congestion?
• Is the traffic on the main street so heavy that drivers on the side street will try to cross when it is unsafe?
• Are there so many pedestrians trying to cross a busy main street that confusing, congested, or hazardous conditions result?
• Are there so many school children trying to cross the street at the same time that they need special controls for their protection? If so, is a traffic signal the best solution?
• Are signals at this location going to help drivers maintain a uniform pace along the route without stopping unnecessarily?
• Does the collision history indicate that signal controls will reduce the probability of collisions?
• Do two arterials intersect at this location and will a signal help improve the flow of traffic?
• Is there a combination of the above conditions which indicates that a signal will be an improvement rather than a detriment?

To aid them in answering these questions, engineers compare the existing conditions against nationally-accepted minimum guidelines. Experienced traffic engineers established these guidelines (warrants) from many observations at intersections throughout the country. Where the guidelines were met, the signals generally were operating effectively with good public compliance. Where the guidelines were not met, public compliance was reduced, and additional hazards resulted.

A traffic signal that decreases accidents and improves the flow of traffic is an asset to any community. On the other hand, an ill-advised or poorly designed signal can be a source of danger and annoyance to all that use the intersection: pedestrians, cyclists, and drivers alike.

5. What is a Traffic Signal Warrant?

The use of the word "warrant" in the Manual on Uniform Traffic Control Devices (MUTCD) is unfortunate since this word implies the idea of "sanctioned, needed, and approved". However these adjectives do not apply to the warrant guidelines in the MUTCD.*

The MUTCD has eight guidelines (called warrants), which establish certain minimum thresholds below which a traffic signal should not be installed. Satisfying one or more of these warrants does not mean that the city must or should install a traffic signal. In fact, the MUTCD states the following:

• A traffic control signal should not be installed unless one or more of the factors described in this section are met.
• A traffic control signal should not be installed unless an engineering study indicates that installing a traffic control signal will improve the overall safety and/or operation of the intersection.
• A traffic control signal should not be installed if it will seriously disrupt progressive traffic flow.**

*Page 3, The Traffic Signal Book, Fred L. Orcutt, Jr. Prentice Hall, 1993
**Page 4C-1, MUTCD, Millenium Edition, Federal Highway Administration

6. What are the Traffic Signal Warrants?

The following warrant titles and the general supplemental information below them provide some indication of what parameters are looked at by traffic engineers, and are taken from the MUTCD. Refer to the latest edition of the MUTCD for the all of the specific information required and when the criteria for each warrant, or guideline, has been met.

• Warrant One, Eight-Hour Vehicular Volume - This warrant looks at the major and minor total street volumes per hour for eight-hour periods, when the volumes of intersecting traffic are the principal reason for consideration of signal installation. In general, average day volumes of more than 500 vehicles per hour (vph) total on the major street, and/or more than 150 vph on one approach from the minor street will result in this warrant being met.
  
  This warrant also looks at the major and minor traffic volumes for eight-hour periods, for that instance when the traffic volume on the major street is so heavy that traffic on minor streets suffers excessive delay or hazard in entering or crossing the major street. In general, volumes of more than 750 vph total on the major street, and/or more than 75 vph on one approach from the minor street will result in this warrant being met; providing that the signal would not seriously disrupt progressive traffic flows.
• Warrant Two, Four-Hour Vehicular Volume - A traffic signal may be warranted at some intersections when each of any four hours of an average day has a total traffic volume on the major street and an approach traffic volume on the minor street, which if plotted would fall above the curve of Figures 4C-1 and/or 4C-2 of the MUTCD.
• Warrant Three, Peak Hour Volume - The peak hour volume warrant is intended for application when traffic conditions are such that for one hour of the day minor street traffic suffers undue traffic delay in entering or crossing the major street, as determined on where the plotted traffic volumes would fall with respect to the curves of Figures 4C-3 and 4C-4 of the MUTCD.
• Warrant Four, Pedestrian Volume - This warrant looks at pedestrian volume crossing the major street at an intersection or at a mid-block location during an average day. In general, pedestrian volumes of more than 100 pedestrians per hour for any four hours, and/or more than 190 pedestrians during any one hour period will result in this warrant being met.
• Warrant Five, School Crossing - A traffic signal may be warranted at an established school crossing when a traffic engineering study of the frequency and adequacy of gaps in the vehicular traffic stream as related to the number and size of groups of school children indicates that the available time for the school children to cross the street is inadequate.
• Warrant Six, Coordinated Signal System - A traffic signal may be warranted at intersections where they would not otherwise be warranted in order to maintain proper grouping of vehicles (to establish and maintain platoons of vehicles for effective traffic signal coordination) and to effectively regulate group speed.
• Warrant Seven, Crash Experience - A traffic signal may be warranted at some intersections when less restrictive remedies and enforcement has failed to reduce the vehicular collision rate; and five or more correctable collisions have occurred within a 12-month period; and there are volumes of vehicles and pedestrians of not less than 80 % of the requirements specified in Warrant One; and the new signal will not seriously disrupt progressive (coordinated) traffic flows.
• Warrant Eight, Roadway Network - A traffic signal may be warranted at some intersections to encourage concentration and organization of traffic flow networks when there is an entering traffic volume of at least 1,000 vph during the peak hour of a typical workday, and which has five year projected traffic volumes – based upon an engineering traffic study – that meet one or more of Warrants One, Two, and Three during at average workday; or which has a total entering volume of at least 1,000 vph for each of any five hours on a weekend.

7. What is the justification for a left turn arrow?

Left Turn Signal Phasing - Left turn signal phases facilitate left turning traffic and usually improve the safety of the intersection for left turning vehicles. However, this is done at the expense of the amount of green time available for through traffic and will usually reduce the capacity of the intersection. Left turn arrows also result in longer cycle lengths, which will in turn have a detrimental effect by increasing stops and delays. Pedestrian delays may be increased, resulting in pedestrians ignoring the pedestrian signal.

While phases for protected left turning vehicles are the most popular and most often added phases, other methods of handling left turn conflicts should be considered first. Potential solutions include prohibited left turns and geometric improvements.

Left Turn Phase Criteria - The left turn phase criteria suggested below are a combination of left turning phasing used in several states in the United States and the result of considerable research and study. These warrants are not mandated by the Manual on Uniform Traffic Control Devices (MUTCD) and are provided for information purposes only. Suggested warrants are as follows:

• Volumes - Consider left turn phasing when the product of left turning and opposing volumes during peak hours exceed 100,000 on a four-lane street, or 50,000 on a two-lane street (one approach lane). Also, the left turn volume for two or more approach lanes should be greater than two vehicles per cycle during the peak hour period. Volumes meeting these levels indicate that a left turn phase may be justified and further study of the intersection is recommended.
• Delay - Consider installing left turn phasing if a left turn total delay of two vehicle hours or more occur in a peak hour on a critical approach. Also, there should be a minimum left turn volume of greater than two vehicles per cycle during peak hour, and the average delay for left turning vehicle should be at least 35 seconds.
• Accident Experience - Install left turn phasing if the critical number of left turn accidents has occurred. For one approach, the critical number is four left turn accidents in one year, or six in two years. For both approaches, the critical number is six left turn accidents in one year, or 10 in two years.

Protected / Permitted Left Turn Phasing - Protected / permitted left turn phasing is a left turn movement of traffic at a signalized intersection having a separate left turn phase in the signal cycle to provide a protected green arrow interval, as well as non-protected circular green interval. Use of the protected / permitted left turn phasing technique is based on the assumption that the need for a protected left turn interval has been established. One of the basic precepts of the protected / permitted left turn phasing, is that the protected green arrow is displayed only when needed in a traffic demand condition. It is therefore emphasized that the protected / permitted left turn phasing technique is an efficient concept as opposed to an accident reduction concept although it will probably offer safer operation than permissive only operation.

Protected Only Left Turn Phasing - When a separate interval is provided to accommodate a left turn without conflicting traffic, and left turns are prohibited during the rest of the cycle, protected only left turn phasing occurs. Although the MUTCD provides no left turn phasing warrants, the traffic control device handbook offers suggested guidelines for separate left turn phasing.

Unprotected Left Turn Phasing - Unprotected left turn phasing occurs when an exclusive phase is not provided for left turn vehicles. Left turns are permitted to occur through gaps in the opposing traffic flow. Separate left turn lanes may or may not be provided.

8. How do pedestrian signals work?

The pedestrian signal provides time for the pedestrians to enter the street on the steady walk signal or walking person symbol and to finish crossing the street on the flashing don't walk or upraised hand signal. The signal is normally activated by a push button, which causes the traffic signal controller to operate a pre-programmed timed sequence of walk and flashing don't walk indications.

Pedestrian signals consist of walk and don't walk signals or the international symbols displaying a person walking for the walk indication, and a hand for the don't walk indication. The walk indication is displayed in white, and the don't walk indication is displayed in Portland orange.

The pedestrian signal sequence begins when the walk indication is illuminated, and this sequence is typically 4-7 seconds long. This sequence should be long enough for a pedestrian to leave the curb and begin crossing the street before the clearance interval begins.

The pedestrian clearance interval consists of the flashing don't walk indication. During this interval the pedestrian is expected to complete their crossing of the street. The pedestrian should not, however, begin crossing the street on the flashing don't walk indication. The pedestrian clearance interval is typically calculated by dividing the street width by an assumed walking speed of four feet per second, unless a special study indicates that a longer time interval is needed for all pedestrian to safely cross the street, i.e. a slower walking speed of 3.5 feet per second is often used for elderly pedestrians. The actual distance used to calculate the clearance interval is usually the distance from the curb on the near side of the street to the center of the last traffic lane on the far side of the street.

The don't walk indication, steadily illuminated, means that a pedestrian is not to enter the street in the direction of the pedestrian signal.

WARNING: While pedestrians have the right of way at both marked and unmarked crosswalks, both pedestrians and motorists should be very alert when pedestrians are present at a pedestrian signal, since right turn on red movements are allowed unless otherwise prohibited.

9. Is it really necessary for me to push a button to activate the pedestrian signal, or can I just wait for the light to change?

Where buttons are available to pedestrians, it is because the traffic signal is timed for cars, not for people on foot. If you don't activate the pedestrian signal by pushing the button, the traffic light won't give you enough time to safely cross the street. You only need to push the button once for it to be activated.

10. Why does it always say "don't walk" before I've completed crossing the street?

The flashing "don't walk" or upraised hand is a warning to people who have not yet entered the intersections that it's too late to safely cross the street before the traffic signal changes allowing cars to proceed. Signals are timed to allow plenty of time for people who have already started walking to safely cross the street.

11. Can I count on a safe crossing if I carefully follow the pedestrian signals?

The signals assign your legal rights in the intersection. However, it is important to be cautious when crossing busy intersections.

The following suggestions are offered in the interest of safety:

• Cross intersections defensively when crossing the street
• Regardless of the availability of signals, cross as quickly as possible
• Minimize your time in the roadway
• Always watch for turning vehicles

You have the legal right to be there, but that doesn't protect you from the carelessness of some motorists.

12. What are the pedestrian rights and responsibilities when walking along or crossing a street?

Pedestrian rights and responsibilities are found in Section 316.130 of the Florida Statutes, but a list of some of those rights and responsibilities is given below. The following list is not represented as being exhaustive, and the reader is directed to the statutes for more complete information.

Florida Statute 316.130. Pedestrian obedience to traffic control devices and traffic regulations
(1) A pedestrian shall obey the instruction of any official traffic control device specifically applicable to the pedestrian unless otherwise directed by a police officer.

Pedestrians shall be subject to traffic control signals at intersections as provided in s. 316.075, but at all other places pedestrians shall be accorded the privileges and be subject to the restrictions stated in this chapter. Where sidewalks are provided, no pedestrian shall, unless required by the circumstances, walk along and upon the portion of a roadway paved for vehicular traffic. Where sidewalks are not provided, any pedestrian walking along and upon a highway shall, when practicable, walk only on the shoulder on the left side of the roadway in relation to the pedestrian's direction of travel, facing traffic which may approach from the opposite direction. No person shall stand in the portion of a roadway paved for vehicular traffic for the purpose of soliciting a ride, employment, or business from the occupant of any vehicle. No person shall stand on or in proximity to a street or highway for the purpose of soliciting the watching or guarding of any vehicle while parked or about to be parked on a street or highway.

When traffic control signals are not in place or in operation, the driver of a vehicle shall yield the right of way, slowing down or stopping if need be to so yield, to a pedestrian crossing the roadway within a crosswalk when the pedestrian is upon the half of the roadway upon which the vehicle is traveling or when the pedestrian is approaching so closely from the opposite half of the roadway as to be in danger. Any pedestrian crossing a roadway at a point where a pedestrian tunnel or overhead pedestrian crossing has been provided shall yield the right of way to all vehicles upon the roadway. No pedestrian shall suddenly leave a curb or other place of safety and walk or run into the path of a vehicle which is so close that is impossible for the driver to yield.

Whenever any vehicle is stopped at a marked crosswalk or at any unmarked crosswalk at an intersection to permit a pedestrian to cross the roadway, the driver of any other vehicle approaching from the rear shall not overtake and pass such stopped vehicle. Every pedestrian crossing a roadway at any point other than within a marked crosswalk or within an unmarked crosswalk at an intersection shall yield the right of way to all vehicles upon the roadway. Between adjacent intersections at which traffic control signals are in operation, pedestrians shall not cross at any place except in a marked crosswalk. No pedestrian shall, except in a marked crosswalk, cross a roadway at any other place than by a route at right angles to the curb or by the shortest route to the opposite curb. Pedestrians shall move, whenever practicable, upon the right half of crosswalks. No pedestrian shall cross a roadway intersection diagonally unless authorized by official traffic control devices, and, when authorized to cross diagonally, pedestrians shall cross only in accordance with the official traffic control devices pertaining to such crossing movements.

Notwithstanding other provisions of this chapter, every driver of a vehicle shall exercise due care to avoid colliding with any pedestrian or any person propelling a human-powered vehicle and give warning when necessary and exercise proper precaution upon observing any child or any obviously confused or incapacitated person.

13. When is a crosswalk unsafe?

A number of years back, the City of San Diego published some startling results of a very extensive study of the relative safety of marked and unmarked crosswalks. San Diego looked at 400 intersections for five years (without signals or four-way stops) that had a marked crosswalk on one side and an unmarked crosswalk on the other. About 2.5 times as many pedestrians used the marked crosswalk, but about six times as many accidents were reported in the marked crosswalks. Long Beach studied pedestrian safety for three years (1972-1974) and found eight times as many reported pedestrian accidents at intersections with marked crosswalks than at those without. One explanation of this apparent contradiction of common sense is the false security pedestrians feel at the marked crosswalk. Two painted lines do not provide protection against an oncoming vehicle and the real burden of safety has to be on the pedestrian to be alert and cautious while crossing any street. A pedestrian can stop in less than three feet, while a vehicle traveling at 25 miles per hour will require 60 feet and at 35 miles per hour approximately 100 feet.

Crosswalks exist at all intersections unless signs prohibit pedestrian crossing. Some of these crosswalks are marked with painted lines, but most of them are not. Pedestrian crosswalk marking is a method of encouraging pedestrians to use a particular crossing. Such marked crossings may not be as safe as an unmarked crossing at the same location. Therefore, crosswalks should be marked only where necessary for the guidance and control of pedestrians, to direct them to the safest of several potential routes.

14. Do marked crosswalks provide better pedestrian safety than unmarked crosswalks?

Not always. The city receives frequent requests to install marked crosswalks at uncontrolled intersections or at some mid-block location between uncontrolled intersections. An uncontrolled intersection is one without stop signs, yield signs, or traffic signals. These requests almost always come from the sincere belief held by some citizens that a marked crosswalk provides some kind of additional protection to the pedestrians who use them. Unfortunately, this is a common misconception that can be extremely hazardous.

There have been many site studies of pedestrian safety at marked and unmarked crosswalks at uncontrolled intersections.

The primary thrust of these studies is that marked crosswalks give pedestrians a false sense of security. While the crosswalk markings are very obvious to the pedestrian, they are often much less visible to the motorists who drive over them. Pedestrians must always act defensively when motorists are in close proximity to them, but some pedestrians think that white pavement markings will somehow stop, or slow down, a moving vehicle, and this is obviously just not the case.

15. Why are the words "walk" and "don't walk" being replaced by symbols?

Transportation engineers worldwide are moving toward the use of symbol signs in place of word signs because they are easier for people to comprehend in a shorter amount of time. Easily recognized symbols also accommodate people who can't read English.

In the case of pedestrian signals, both word and symbol signs are currently in use. Here's what they mean. "Walk" or walking pedestrian symbol means you may begin crossing. A flashing or steady "Don't Walk" or an upraised hand symbol means it's too late to begin crossing. Don't enter the street but finish crossing if you have already started.

16. What is the roadside clear zone?

The State of Florida defines the roadside clear zone as that area outside the traveled way, available for use by errant vehicles. The roadside clear zone is an area in the median or on the side of the street, off the pavement, that is kept clear of fixed objects. If motorists drive off the road, for whatever reason, the motorists have the leeway to regain control of their vehicles and safely steer back onto the street. The clear zone also permits disabled vehicles to pull out of the traffic lanes where curb and sidewalks are not installed. Clear zones are established to provide an extra margin of safety for motorists.

17. Why can't we use speed bumps on our block?

The speed bump is an increased hazard to the unwary, a challenge to the daredevil, a disruption of the movement of emergency vehicles, and the cause of an undesirable increase in noise.

Courts have held public agencies liable for personal injuries resulting from faulty design. Because speed bumps have considerable potential for liability suits, many officials have rejected them as a standard traffic control device on public streets.

In addition, tests of various experimental designs have demonstrated the physical inability of a speed bump to successfully control all types of light-weight and heavy-weight vehicles. The drive of a softsprung sedan is actually encouraged to increase speed for a better ride over a bump that may cause other motorists to lose control.

18. Are traffic control devices on private property required to meet State standards?

State law requires traffic control devices, including those signs and pavement markings on private property where the public is invited, to meet state standards adopted by the Florida Department of Transportation. Florida Statutes, Section 316.0747, state: "It is unlawful for any non-governmental entity to use any traffic control device at any place where the general public is invited, unless such device conforms to the uniform system of traffic control devices adopted by the Department of Transportation pursuant to this chapter."

The Manual on Uniform Traffic Control Devices (MUTCD), published by the U.S. Department of Transportation, is the national standard for traffic control devices. The Florida Department of Transportation has adopted the MUTCD as the State standard, by Rule 14-15.010.

The MUTCD states that:

• Parking space striping must be white (Sec. 38-18)
• Lane lines between traffic lanes in the same direction must be white (Sec. 38-40)
• Center lines between traffic in opposing direction must be yellow (Sec. 28-01)
• Arrows on the pavement must be white (Sec. 38-19)
• Crosswalks and crosswalk lines must be white (Sec. 38-17)
• Stop lines (stop bars) must be white (Sec. 28-16)
• Street names signs must have 6" high lettering and should be reflectorized (Sec. 2D-38)

Sign Intallation: In business, commercial, or residential districts where parking and/or pedestrian movement is likely, the clearance to the bottom of a sign shall be at least 7' above the edge of the pavement. In rural areas, the clearance to the bottom of a sign shall be at least 5' above the edge of the pavement (Sec. 2A-18).

Lateral clearance for regulatory and warning signs or small directional signs should be 6'-12' from the edge of the pavement or traveled way in rural areas. In urban areas, signs generally are mounted alongside the roadway in the space between the curb and the sidewalk. Although 2' is recommended as a working urban minimum, a clearance of 1' from the curb face is permissible where a sidewalk width is limited (Sec. 2A-19).

19. What is Florida law in regard to school speed zones and school buses?

In Florida, school zones are governed by the Florida traffic laws, Florida Statutes, Section 316.1895. This statute states that "a school zone speed limit may not be less than 15 miles per hour except by local regulation. No school zone speed limit shall be more than 20 miles per hour in an urbanized area, as defined in S. 334.03. Such speed limit may be in force only during those times 30 minutes before, during, and 30 minutes after the periods of time when people are arriving at a regularly-scheduled breakfast program or a regularly-scheduled school session and leaving a regularly scheduled-school session."

The statute also states that "Permanent signs designating school zones and school zone speed limits shall be uniform in size and color, and shall display the times during which the restrictive speed limit is enforced clearly designated thereon. The Department of Transportation shall establish adequate standards for the signs."

Different types of speed limit signs are used for school zones in Florida. Some have flashers, which serve the purpose of advising motorists when the school zones are in effect. When these flashers are set and used properly, they are very effective. They alert the motorist to the need for caution and slower driving when the appropriate conditions exist. A school speed limit sign without flashers is just as legally binding as a flasher sign. Drivers are reminded to be especially alert during those hours when children are on the streets.

Chapter 316.172 of the Florida Statutes indicates that traffic must stop for school buses. This law states that:

(1)(a) Any person using, operating, or driving a vehicle on or over the roads or highways of this state shall, upon approaching any school bus which displays a stop signal, bring such vehicle to a full stop while the bus is stopped, and the vehicle shall not pass the school bus until the signal has been withdrawn. A person who violates this section commits a moving violation, punishable as provided in Chapter 318.

Any person using, operating, or driving a vehicle that passes a school bus on the side that children enter and exit when the school bus displays a stop signal commits a moving violation, punishable as provided in Chapter 318, and is subject to a mandatory hearing under the provisions of s. 318.19.

(2) The driver of a vehicle upon a divided highway with an unpaved space of at least 5', a raised median, or a physical barrier is not required to stop when traveling in the opposite direction of a school bus which is stopped in accordance with the provisions of this section.