Where required MUTCD offers guidance regarding factors to consider in an engineering
study in deciding whether an APS is needed. Factors include:
"Potential demand for APS
A request for APS
Traffic volumes during times when pedestrians might be present; including
periods of low traffic volumes or high turn-on-red volumes
Complexity of traffic signal phasing.
Complexity of intersection geometry."
Avoidance of ambiguity
Several statements address ambiguity:
"Information provided by an APS shall clearly indicate which pedestrian
crossing is served by each device."
"When used, verbal message shall provide a clear message of the Walk
interval and to which crossing it applies."
"Provision of different sounds for crosswalks in different directions
has been found to give ambiguous information to blind pedestrians."
"Pushbuttons should clearly indicate which crosswalk signal is actuated
by each pushbutton."
"In choosing audible tones, possible extraneous sources of sound should
be considered."
WALK indication
Standards:
If APS have tones, they shall have a tone for the walk interval.
WALK tones shall have a faster repetition rate than an associated
pushbutton locator tone.
Shall operate day and night.
If used, the speech message for a WALK signal shall be the term "Walk
sign."� which may be followed by the name of the street to be crossed.
"Vibrotactile devices, where used, shall indicate that the walk interval
is in effect, and for which direction it applies, through the use of
a vibrating directional arrow or some other means." Vibrotactile pedestrian
devices "should be located next to, and on the same pole as, the pedestrian
pushbutton, if any, and adjacent to the intended crosswalk."
Volume
Volume: Audible tones "shall be audible from the beginning of the associated
crosswalk."
WALK tones should be no louder than the locator tone except when there
is optional activation to provide a louder signal tone for a single
pedestrian phase.
WALK signals and locator tones should respond to ambient sound, be
no more than 5dB louder than ambient sound, and be 89 dB max.
Locator tones should be audible 6 to 12 feet from the pushbutton or
to the building line, whichever is less.
Developing
Standards and Guidelines Pedestrian pushbuttons Pushbuttons
Shall activate both the Walk interval and the accessible pedestrian
signals
Should contrast with the housing
May have locator tones
Locator tones shall be easily locatable
Locator tones shall repeat at one-second intervals and shall have
a duration of 0.15 sec max
At locations with pretimed or nonactuated signals, pushbuttons may be
used to activate the APS.
Location of pushbuttons
Pushbuttons should be located
adjacent to a level all-weather surface,
on an accessible route to the curb ramp
within 1.5 m (5 ft) of the crosswalk extended,
within 3 m (10 ft) of the edge of the curb, shoulder, or pavement
Where two APS pushbuttons are located on the same corner, the pushbuttons
should be separated by a distance of at least 3m (10 ft).
Pushbutton signage
Tactile arrows
should be oriented parallel to the associated crosswalk
should have high visual contrast
Name of the street in Braille may be provided.
Audible beaconing
The audible tones may be made louder for the subsequent pedestrian phase,
up to a max of 89dB, by holding down the pushbutton for a minimum of 3
seconds.
may also alternate back and forth across the crosswalk to provide
optimal beaconing.
Other
APS "...shall not be limited in operation by the time of day or day of
week."
When used, APS shall be used in combination with pedestrian signal timing.
A speech message when the WALK signal is not on shall be the term "Wait."
If the pedestrian clearance time is sufficient only to cross from the
curb to a median (of sufficient width for pedestrians to wait) and accessible
pedestrian detectors are used, an additional accessible pedestrian detector
should be provided in the median.
Revisions
The MUTCD is revised on a continuous basis, following Federal regulatory
procedures. Users should check current provisions on the MUTCD website
at mutcd.fhwa.dot.gov.
