Signals and Signs
Traffic control devices are often used by traffic engineers to improve safety and access for pedestrians. In addition to marked crosswalks, several other devices are available. For information on accessible pedestrian signals, visit the Accessible Pedestrian Signal web site. This section includes:
- Pedestrian Signals
- Pedestrian Signal Timing
- Traffic Signal Enhancements
- Right-Turn-On-Red Restrictions
- Signing
Traffic signals create gaps in the traffic flow, allowing pedestrians to cross the street. They should allow adequate crossing time for pedestrians and an adequate clearance interval based upon a maximum walking speed of 3.5 ft/s. Signals are particularly important at high-use, midblock crossings on higher speed roads, multi-lane roads, or at highly congested intersections. National warrants from the Manual on Uniform Traffic Control Devices (MUTCD) are based on the number of pedestrians and vehicles crossing the intersection, among other factors. However, judgment must also be used on a case-by-case basis. For example, a requirement for installing a traffic signal is that there are a certain number of pedestrians present. If a new facility is being built—a park or recreational path, for example—there will be a new demand, and the signal could be installed in conjunction with the new facility based on projected crossing demand. There may also be latent demand if a destination is not currently accessible, but could become so with new facilities or redesign.
In downtown areas, signals are often closely spaced, sometimes every block. Timed sequencing of signals should ensure that the amount of time allotted per cycle for pedestrian crossings is sufficient. Signals are usually spaced farther apart in suburban or outlying areas, but similar considerations for pedestrian phasing should be made. When high or regular pedestrian traffic exists during a majority of the day, fixed-time signals should be used to consistently allow crossing opportunities. Pedestrian actuation should only be used when pedestrian crossings are intermittent and should be made accessible to all pedestrians, including those with disabilities.
Purpose
- Provide intervals in a traffic system where pedestrians can cross streets safely
Considerations
- Where pedestrian traffic is regular and frequent, pedestrian phases should come up automatically. Pedestrian actuation should only be used when pedestrian crossings are intermittent.
- Signal cycles should be kept short (ideally 90 seconds maximum) to reduce pedestrian delay. Pedestrians are very sensitive to delays.
- Marked crosswalks at signals should always be installed at all four legs. They encourage pedestrians to cross at the signal and discourage motorists from encroaching into the crossing area.
Estimated cost
$40,000 to $200,000/signal
Pedestrian Signals
Pedestrian signal indications should be used at all traffic signals, unless the signal is located on a highway where walking is prohibited.
The international pedestrian symbol signal is preferable and is recommended in the MUTCD. Existing WALK and DON'T WALK messages may remain for the rest of their useful life but should not be used for new installations. Pedestrian signals should be clearly visible to the pedestrian at all times when in the crosswalk or waiting on the far side of the street. Larger pedestrian signals can be beneficial in some circumstances (e.g., where the streets are wide). Signals may be supplemented with audible or other messages to make crossing information accessible for all pedestrians, including those with vision impairments. The decision to install audible pedestrian signals should consider the noise impact on the surrounding area. Visit PBIC's web site for much more extensive information on the use of accessible pedestrian signals (APS) and the types of APS technologies available.
Purpose
- Indicate appropriate time for pedestrians to cross
- Provide pedestrian clearance interval
Considerations
Estimated cost
$20,000 to $40,000 for all four legs
Pedestrian Signal Timing
There are several types of signal timing for pedestrian signals, including concurrent, exclusive, "leading pedestrian interval" (LPI), and all-red interval. In general, shorter cycle lengths and longer walk intervals provide better service to pedestrians and encourage better signal compliance. For optimal pedestrian service, fixed-time signal operation usually works best. Pedestrian pushbuttons may be installed at locations where pedestrians are expected intermittently. Quick response to the pushbutton or feedback to the pedestrian (e.g.- indicator light comes on) should be programmed into the system. When used, pushbuttons should be well-signed and within reach and operable from a flat surface for pedestrians in wheelchairs and with visual disabilities. They should be conveniently placed in the area where pedestrians wait to cross. Section 4E.09 within the MUTCD provides detailed guidance for the placement of pushbuttons to ensure accessibility.
In addition to concurrent pedestrian signal timing (where motorists may turn left or right across pedestrians' paths after yielding to pedestrians), exclusive pedestrian intervals stop traffic in all directions. Exclusive pedestrian phasing is most appropriate in locations with high pedestrian volumes (especially if higher than motor vehicle volumes), high turning movement conflicts, or high speed locations. With concurrent signals, pedestrians usually have more crossing opportunities and have to wait less. Unless a system is willing to take more time from vehicular phases, pedestrians will often have to wait a long time for an exclusive signal. This is not very pedestrian-friendly, and many pedestrians will simply choose to ignore the signal and cross if and when there is a gap in traffic, negating the potential safety benefits of the exclusive signal. Exclusive pedestrian phases do introduce a problem for pedestrians with visual impairments, as the audible cues associated with surging parallel traffic streams are no longer present, which makes it difficult to know when to begin crossing.
A simple, useful change is the LPI. An LPI gives pedestrians an advance walk signal before the motorists get a green light, giving the pedestrian several seconds to start in the crosswalk where there is a concurrent signal. This makes pedestrians more visible to motorists and motorists more likely to yield to them. This advance crossing phase approach has been used successfully in several places, such as New York City, for two decades and studies have demonstrated reduced conflicts for pedestrians. The advance pedestrian phase is particularly effective where there is a two-lane turning movement. To be useful to pedestrians with vision impairments, an LPI needs to be accompanied by an audible signal to indicate the WALK interval.
There are some situations where an exclusive pedestrian phase may be preferable to an LPI, such as where there are high-volume turning movements that conflict with the pedestrians crossing.
Purpose
- An exclusive phase provides a pedestrian crossing phase with no conflicting traffic.
- A short all-red clearance interval provides a better separation between cars and pedestrians.
Considerations
- An exclusive phase usually creates a longer cycle length and a longer wait between crossings.
- An exclusive phase may eliminate the ability to synchronize timing at adjacent traffic signals.
- Exclusive phasing is most applicable to areas with high pedestrian volumes (e.g., more than 1,200 pedestrian crossings per day), where there are high conflicts with turning vehicles, or where there are high speed turns that would put a crossing pedestrian in greater peril.
- Exclusive timing eliminates conflicts with turning vehicles if pedestrians and motorists obey their signals and there is a prohibition on right turn on red.
- The benefits of this treatment may not extend to vision-impaired pedestrians.
- Wider intersections require longer cycle lengths.
- Longer walk or pedestrian clearance intervals may also lead to longer cycle lengths.
- Use fixed-time operation unless pedestrian arrivals are intermittent.
Estimated cost
Adjusting signal timing is very low cost and requires a few hours of staff time to accomplish. New signal equipment ranges from $40,000 to $200,000.
Traffic Signal Enhancements
A variety of traffic signal enhancements that can benefit pedestrians and bicyclists are available. These include automatic pedestrian detectors, larger traffic signals that better ensure visibility, signal placement to prohibit motorists waiting at a red light from seeing other signals and anticipating green lights, and countdown signals to provide pedestrians with information about the amount of time remaining in a crossing interval.
Countdown signals may be designed to begin counting down at the beginning of the walk phase (preferred) or at the beginning of the clearance (flashing DON'T WALK) interval. Countdown signals can be on fixed-time or pushbutton operation.
Since pedestrian pushbutton devices are not activated by about one-half of pedestrians (even fewer activate them where there are sufficient motor vehicle gaps), new "intelligent" microwave or infrared pedestrian detectors are now being installed and tested in some U.S. cities. These automatically activate the red traffic and WALK signals when pedestrians are detected. Detectors can also be used to extend the crossing time for slower moving pedestrians in the crosswalk. Automatic pedestrian detectors have been found to improve pedestrian signal compliance and also reduce pedestrian conflicts with motor vehicles. However, they are still considered experimental and their reliability may vary under different environmental conditions.
Purpose
- Improve pedestrian accommodation at signalized crossings
Considerations
- Pedestrian signals need to indicate the crossing interval by visual, audible, and/or tactile means if pedestrians with vision impairments are to take advantage of them.
Estimated cost
About $10,000 to add new pedestrian signals and mark crosswalks at all four legs.
Right-Turn-On-Red Restrictions
A permissible Right-Turn-on-Red (RTOR) was introduced in the 1970s as a fuel-saving measure and has sometimes had detrimental effects on pedestrians. While the law requires motorists to come to a full stop and yield to cross-street traffic and pedestrians prior to turning right on red, many motorists do not fully comply with the regulations, especially at intersections with wide turning radii. Motorists are so intent on looking for traffic approaching on their left that they may not be alert to pedestrians approaching on their right. In addition, motorists usually pull up into the crosswalk to wait for a gap in traffic, blocking pedestrian crossing movements. In some instances, motorists simply do not come to a full stop.
One concern that comes up when RTOR is prohibited is that this may lead to higher right-turn-on-green conflicts when there are concurrent signals. The use of the leading pedestrian interval (LPI) can usually best address this issue. Where pedestrian volumes are very high, exclusive pedestrian signals should be considered.
Prohibiting RTOR should be considered where and/or when there are high pedestrian volumes, or where there is a proven problem with motorists conflicting with pedestrians. This can be done with a simple sign posting, although there are some options that are more effective than a standard sign. For example, one option is a larger 762-mm by 914-mm (30-in by 36-in) NO TURN ON RED sign, which is more conspicuous. For areas where a right-turn-on-red restriction is needed during certain times, time-of-day restrictions may be appropriate. A variable-message NO TURN ON RED sign is also an option.
Purpose
- Increase pedestrian safety and decrease crashes with right-turning vehicles
Considerations
- Prohibiting RTOR is a simple, low-cost measure. Together with a leading pedestrian interval, the signal changes can benefit pedestrians with minimal impact on traffic.
- Prohibiting RTOR may cause congestion at locations with high right turn movements
- Part-time RTOR prohibitions during the busiest times of the day may be sufficient to address the problem.
- Signs should be clearly visible to right-turning motorists stopped in the curb lane at the crosswalk.
Estimated cost
$30 to $150 per NO TURN ON RED sign plus installation at $200 per sign. Electronic signs have higher costs.
Signing
Signs can provide important information that can improve road safety. By letting people know what to expect, there is a greater chance that they will react and behave appropriately. For example, giving motorists advance warning of an upcoming pedestrian crossing or that they are entering a traffic-calmed area will alert them to modify their speed. Sign use and movement should be done judiciously, as overuse breeds noncompliance and disrespect. Too many signs may also create visual clutter and signs can get lost. All signs should be periodically checked to make sure that they are in good condition, free from graffiti, reflective at night, and continue to serve a purpose.
Regulatory signs, such as STOP, YIELD, or turn restrictions require certain driver actions and can be enforced. Warning signs can provide helpful information, especially to motorists and pedestrians unfamiliar with an area. Some examples of signs that affect pedestrians include pedestrian warning signs, motorist warning signs, NO TURN ON RED signs, and guide signs.
Advance pedestrian warning signs should be used except in very urban situations where short blocks don't provide appropriate distances for locating the signs. They should always be used where pedestrian crossings may not be expected by motorists, especially if there are many motorists who are unfamiliar with the area.
Purpose
- Provide regulation, warning, or information to road users as to what to expect and how to behave
Considerations
- Overuse of signs breeds noncompliance and disrespect. Too many signs can lead to visual clutter with the result that a driver is not likely to read or pay attention to any of the signs.
- Signs should be checked to assure adequate nighttime reflectivity.
Estimated cost
$50 to $150 per sign plus $150 /sign in installation costs.
