Traffic Signals

Signalizing busy intersections and providing signalized crosswalks may help create safe routes to schools for children. New traffic signals are very expensive and must be warranted or they could cause more harm than good. Warrants for installing traffic signals are provided in the MUTCD 2009 Edition Chapter 4C.

Traffic signals are the highest form of traffic control. However, their benefit to the pedestrian network is contingent upon the application of several principles including;

Mark all legs of an intersection:
Pedestrian paths should be provided on all sides of an intersection where pedestrian crossings are desired. A school walking route plan may limit crossings to three or fewer legs, but all options should be available for school officials to select the most desirable crosswalks to use.
Provide pedestrian signal heads in all directions:
Pedestrian signal indications (Walk, flashing Don’t Walk, Don’t Walk, or walking man and raised hand symbols) should be provided at every signalized crossing.
Only use pedestrian pushbuttons if they are needed:
Push buttons are generally appropriate at locations with low or intermittent pedestrian activity. If used, they should be in clear view and wheelchair accessible.
Install ADA-compliant curb ramps and landings on all corners:
Fully accessible curb ramps and landings should be in place on all corners to provide a safe place for people to wait.
Paint stop bars for motor vehicles on all approaches:
Stopping motor vehicles in advance of the marked crosswalk keeps the crosswalk clear for pedestrians and can reduce right-on-red conflicts
Install curb ramps on each corner:
Two ADA-compliant curb ramps per corner; eight per intersection
Provide streetlights on all four corners.
Proper illumination is critical at signalized intersections. Children are smaller and more difficult for motorists to see, especially in darker conditions, such as occur during arrival in the winter months.

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Treatment: Traffic Signal Installations

Description/Purpose

Signals that control the flow of traffic and provide sufficient time for safe and efficient pedestrian crossings.

Expected Effectiveness

When signals are installed at appropriate locations (i.e. where warranted) they should improve pedestrian safety and also reduce the severity of motor vehicle crashes, even though total vehicle crashes (e.g. including rear-end collisions) may increase. Research is limited on the effect of traffic signals on pedestrian crashes, although some pedestrian signal timing schemes have been shown to significantly reduce pedestrian crash risk.

Costs

Costs range from $250,000-$500,000 for purchase and installation (Washington State Department of Transportation, n.d.).

Keys to Success

  • Signal cycles should be kept short.
  • Marked crosswalks encourage pedestrians to cross at the signal.
  • Pedestrian actuation (pushbuttons) should only be used if the pedestrian volume is low enough to support it and must be placed in accessible locations. Consider audible signals if students with visual impairments are present.

Key Factors to Consider

  • Potential increase of vehicular crashes (especially rear-end).
  • Potential traffic diversion to adjacent streets.

Evaluation Measures

  • Motor vehicle-pedestrian crashes.
  • Pedestrian ability to complete their crossing before the steady DON’T WALK is displayed.
  • Signal compliance of pedestrians.

Timing

The signal phasing and/or timing can be modified to increase the time available for pedestrians to cross, to give priority to pedestrians at intersections, and/or to temporarily separate motor vehicle and pedestrian crossings. The timing or phasing of traffic signals is a complex issue, impacted by the signal timing itself as well as other conditions at the crossing including pedestrian and motorist behaviors. Factors that contribute to the complexity of traffic signal timing and phasing include;

  • Duration of time pedestrians must wait for the ‘Walk’ signal,
  • Number of motor vehicle movements that conflict with the pedestrian ‘Walk’ signal,
  • Amount of time that is provided for people to cross the street,
  • Speed at which people are walking,
  • Presence or absence of a button people have to push to get a walk indicator and adequate time to cross the street, and
  • Presence or absence of one or more adult school crossing guards available to assist younger students while crossing the street. (See Adult School Crossing Guard Guidelines for more information.)
  • The potential for conflicts between pedestrians and right-turning motor vehicles.

Treatment: Modified Traffic Signal Phasing and/or Timing

Description/Purpose

The signal phasing and/or timing can be modified to increase the time available for pedestrians to cross, to give priority to the pedestrian at an intersection, and/or to provide a separation in time of motor vehicle and pedestrian crossings. Leading Pedestrian Intervals are an example of a modified signal phasing/timing treatment.

At signalized intersections, Leading Pedestrian Intervals allow the crosswalk/ pedestrian movement to begin crossing 3-6 seconds before the green light is given to motor vehicle traffic in the same direction. This gives pedestrians a head start, making it more likely that drivers will see them while turning. Leading Pedestrian Intervals are appropriate at signalized intersections where there is relatively heavy pedestrian volume or significant conflicts with turning vehicles. A “No Turn On Red” or “No Turn On Red When Pedestrians Are Present” sign should be considered in such situations, according to the 2009 MUTCD.

Expected Effectiveness

Studies of exclusive pedestrian timing have shown a reduction in pedestrian crashes by 50 percent in some downtown areas with high pedestrian volumes and low vehicle speeds and volumes. Other signal modifications have also resulted in a decrease in motor vehicle-pedestrian conflicts at intersections (e.g., Leading Pedestrian Interval).[Zegeer, Opiela, & Cynecki, 1985]

Costs

The cost for adjusting signal timing is relatively low. The cost for installing new signals ranges from $30,000 to $140,000 (PEDSAFE 2004).

Keys to Success

  • Ensure that signals are placed so that they are visible to pedestrians and pushbuttons, if provided, are easy to reach.
  • To ensure pedestrians gain the full benefit of the leading pedestrian interval, a “No Turn on Red” (R10-11) sign should be posted to prevent motorists from turning into crossing pedestrians. At locations where it is desirable to allow drivers to turn on red outside of school hours, a plaque (R10-20aP) can be placed beneath the “No Turn on Red” sign stating the hours during which it the restriction is in effect.

Key Factors to Consider

  • Signal cycles should be kept fairly short to minimize pedestrian delay, but wider intersections may require longer cycle lengths.
  • The speed and volume of motor vehicles should also be considered in signal timing calculations and decisions.

Evaluation Measures

  • Number of conflicts with motor vehicles (especially turning vehicles) and pedestrians at intersections.

Minimize Pedestrian Wait Time

The longer people must wait to cross the street, the more likely they will decide to cross against the signal. Pedestrian wait time can be reduced by shortening the overall signal cycle length or by providing an actuated demand-responsive pedestrian signal. Some pedestrians, especially large groups of children, may need more than the 4 feet per second standard that is used to calculate the time needed for the pedestrian clearance interval. However, longer pedestrian clearance intervals may result in longer signal cycle lengths, and thus longer wait times between ‘Walk’ signals.

 

Increase Pedestrian Clearance Intervals

The pedestrian clearance interval is the time remaining for pedestrians to cross the street once the flashing red hand indication is diplayed on a pedestrian signal. The 2009 MUTCD requires this interval to be calculated based on a minimum walking speed of 3.5 feet per second. However, some pedestrians, especially large groups of children, may need additional time to cross. Consideration should be given to increasing the pedestrian clearance interval if a pedestrian signal must accommodate pedestrians that need more time to cross. However, these considerations should be balanced against the potential for increased wait times between ‘Walk’ signals.

 

This Accessible Pedestrian Push Button not only has an audible tone when the Walk signal comes on, but it also has a vibro-tactile signal. This is for a crosswalk at a midblock traffic signal.

Accessible Pedestrian Signals

Accessible pedestrian signals are audible signals that indicate when it is or is not appropriate to cross the street. Federal ADA guidelines encourage the use of accessible pedestrian signals where there is a need to accommodate pedestrians with visual impairments. Accessible signals come in a variety of designs but include an audible signal and tactile guidance for pedestrians. See the 2009 MUTCD for additional information on accessible signals.

Treatment: Accessible Pedestrian Signals (APS)

Description/Purpose

Audible signals for the visually impaired that indicate when it is or is not appropriate to cross the street.

Expected Effectiveness

  • Audible signals increase awareness of all pedestrians, including those visually impaired, which can lead to fewer pedestrian crashes.[Houten et al., 2000]
  • Can decrease amount of time it takes pedestrians to cross by reducing start up delay.

Costs

Costs range from $700 to $1,150 per signal (Bushell, Poole, Zegeer, Rodriguez, 2013).

Keys to Success

  • Locator tones should be used to help persons with visual impairment find pushbuttons.
  • Appropriate sound levels should be used to limit audible intrusion into the surrounding neighborhood.

Key Factors to Consider

  • APS may be unclear as to which crosswalk it refers.
  • Directional guidance may be needed at wide, skewed or angled intersections.

Evaluation Measures

  • Motor vehicle/pedestrian crashes.
  • Motor vehicle/pedestrian conflicts.
  • Pedestrian crossing ability at current clearance interval.

Pedestrian Pushbuttons

Studies show that 50 percent or fewer pedestrians use the push button to cross, yet if they do not use the button they may not get enough time to cross.[Zegeer, Opiela, & Cynecki, 1985]

Pedestrian pushbuttons are electronic buttons used by pedestrians to change traffic signal timing to accommodate pedestrian crossings. Pushbuttons may be needed at some crossings, but their use should be minimized. Signals can be put in pedestrian “recall” for key time periods of day such as school crossing times. During these periods the pedestrian WALK signal would be displayed every signal cycle. As traffic signals become more complex pedestrian pushbuttons are needed. If buttons exist, pedestrians must push them to get enough time to cross the street. Standard pushbuttons often result in longer waits to cross the street, especially if the pedestrian fails to push the button. Only about 50 percent of pedestrians actually push the buttons based on a FHWA research project.[Zegeer, Opiela, & Cynecki, 1985] If used, they should be clearly visible and within easy reach for people in wheelchairs. Pushbuttons need to be checked periodically to assure that they are working and will place a call into the signal.

Treatment: Pedestrian Pushbuttons

Description/Purpose

Electronic buttons used by pedestrians to change traffic signal timing to accommodate pedestrian crossings.

Expected Effectiveness

  • Improves pedestrian travel time and compliance.
  • Reduces delay to vehicular traffic when pedestrians are not present.

Costs

Costs range from $150 to $1,000 per pushbutton (Bushell, Poole, Zegeer, Rodriguez, 2013).

Keys to Success

  • Must be well signed, easily locatable and within reach of all pedestrians.
  • Should not be used where pedestrian traffic is frequent, as the pedestrian phase should be built into the cycle.
  • Buttons for neighboring crosswalks should be located at least 10 feet from each other.
  • Locator tones can assist visually impaired pedestrians to find the pushbutton.

Key Factors to Consider

  • Visually impaired pedestrians may have difficulty determining if a pushbutton is present.
  • Accessible pedestrian signals may need to be considered at some locations.

Evaluation Measures

  • Pedestrian volume.
  • Pedestrian compliance to WALK/DON’T WALK signal.

No Turn On Red

Standard concurrent signal timing illustrates conflicts that can arise between crossing pedestrians and turning motor vehicles.

NO TURN ON RED sign may reduce some pedestrian conflicts in the near-side crosswalk, but may increase conflicts in the adjacent crosswalk.

Pedestrian and motor vehicle conflicts are a common occurrence when motorists get a green light and pedestrians get a green light or a “Walk” signal at the same time. While motorists are required to stop for pedestrians, conflicts are likely to occur. One solution is to install a “leading pedestrian interval” (LPI) which illuminates the pedestrian ‘Walk’ signal, while the motor vehicle signal remains red. The LPI gives pedestrians an opportunity to start walking and establish a presence in the crosswalk before motorists can begin their turn. The leading pedestrian interval is usually about three seconds or more.

For more information visit PEDSAFE "Leading Pedestrian Interval 2 of 2” St. Petersburg, FL case study #66.

Motorists making a right-turn on a red light are often looking left towards oncoming traffic and do not pay attention to pedestrians who may be approaching from the right. Restricting right-turn-on-red (RTOR) is another way to reduce conflicts between pedestrians and motorists at traffic signals. The RTOR restrictions can be limited to certain times of the day or can apply to all hours, prohibiting motorists from turning right without a green signal. The MUTCD identifies two conditions related to pedestrians when restricted RTOR may be most effective including;

  1. where an exclusive pedestrian phase exists, and
  2. where an unacceptable number of pedestrian conflicts result from RTOR, especially conflicts involving children, older pedestrians, or persons with disabilities.[MUTCD]

When RTOR is prohibited, there may be more right-turn-on-green conflicts between motor vehicles and pedestrians when both the right turning motorists have a green light and the pedestrian has the ‘Walk’ signal on the adjacent crosswalk. The use of leading pedestrian intervals can reduce this effect. Prior to deciding to restrict RTOR, the advantages and disadvantages must be carefully considered.

Treatment: Right-turn-on-red (RTOR) Restrictions

Description/Purpose

RTOR restrictions, which can be limited to certain times of the day or can apply to all hours, prohibit motorists from turning right without a green signal. Restricting this turning movement can reduce conflicts with pedestrians crossing at intersections.

Expected Effectiveness

Studies differ in terms of effectiveness, but the 2009 MUTCD identifies two conditions related to pedestrians when restricted RTOR may be most effective: 1) where an exclusive pedestrian phase exists, and 2) where an unacceptable number of pedestrian conflicts result from RTOR, especially conflicts involving children, older pedestrians, or persons with disabilities.[Zegeer & Cynecki, 1985; MUTCD]

Costs

Costs associated with this treatment will vary widely based on conditions at the site, but are relatively low compared to other treatments. The average cost for a basic sign ranges from $30 to $150 plus installation costs of approximately $200 per sign [PEDSAFE, 2004].

Keys to Success

  • “NO TURN ON RED” signs should be installed adjacent to the signal on the right side of the street and clearly visible to right-turning drivers. Enforcement programs can help establish compliance with the law.

Key Factors to Consider

  • RTOR restrictions may increase delay at intersections for motor vehicles and cause an increase in right-turn-on-green conflicts, but the use of leading pedestrian intervals can reduce this effect.

Evaluation Measures

  • Number of crashes and conflicts.
  • Pedestrian and driver compliance with intersection regulations.

Pedestrian Countdown

Countdown pedestrian signals provide pedestrians with more information on how much time is left and are very well received by pedestrians.

Adequate time must be provided for pedestrians to cross the street safely. Countdown signals help by giving pedestrians information about how much crossing time remains. There is a good deal of confusion by most pedestrians on the meaning of the flashing “Don’t Walk” signal. While it technically means don’t start walking if the pedestrian has not yet started to cross the street, some pedestrians and motorists think that they are supposed to see the ‘Walk’ signal for the entire crossing and they will not have enough time to cross as soon as the flashing begins. The countdown signal shows the number of seconds remaining to cross the street. Some studies have shown that countdown signals reduce the number of stragglers in the street when the signal changes, although some people may still start late. The 2009 MUTCD requires all new pedestrian signals to be countdown signals.

Treatment: Countdown Pedestrian Signals

Description/Purpose

A timer display that counts down the seconds remaining for a pedestrian crossing.

Expected Effectiveness

  • Reduces the number of pedestrians caught in the crosswalk when the cycle ends.
  • Increases pedestrians’ perceived safety.

Costs

Costs range from $300 to $800 per signal.[Safety Toolbox, Countdown Signals]

Keys to Success

  • Should give WALK message with countdown indication each cycle in areas with sufficient pedestrian volume.
  • Signals should be easily visible from both sides of crosswalks.
  • The countdown signals are more applicable where pedestrians are crossing streets with multiple lanes in each direction.

Key Factors to Consider

  • For wide streets, countdown pedestrian signals may be of particular benefit, especially if there are a substantial number of older pedestrians or persons with mobility disabilities who cross.

Evaluation Measures

  • Number of pedestrians caught in the crosswalk when the cycle ends.
  • Perceived pedestrian safety.