Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 17
17
Pedestrian Signals hour crossing the major street (total of all crossings) all fall
above the curve in [Figure 3], or
Pedestrian crossing control devices can be grouped into · For 1 hour (any four consecutive 15-minute periods) of
two types: pedestrian displays and vehicle displays. Pedes- an average day, the plotted point representing the vehicles
trian displays in the United States typically feature a "Walk" per hour on the major street (total of both approaches)
and a "Don't Walk" phase, which operate in either flashing
and the corresponding pedestrians per hour crossing the
or solid state depending on the phase. Other countries use
major street (total of all crossings) falls above the curve in
green and red walking figure symbols instead of the text
[Figure 4]."
description. Vehicle displays are further divided into typical
green/yellow/red signals that are more commonly used at
Alternatives for the two conditions above are also given for
roadway intersections for vehicular traffic control, and the
speed limits (posted, statutory, or 85th percentile) that exceed
newer pedestrian hybrid signals (e.g., PHBs) that feature a
35 mph or intersections that lie within an isolated commu-
modified arrangement of vehicle signal displays. The United
nity with a population of less than 10,000. The pedestrian vol-
States and other countries have warrants (FHWA 2009) for the
ume signal warrant is not to be applied at locations where the
installation of pedestrian signals, but the installation of other
treatments is less standardized. The pedestrian signal warrants distance to the nearest traffic control signal or stop sign is less
in the United States were initially intended for midblock loca- than 300 ft unless the proposed traffic signal will not restrict
tions or conventional intersections that would otherwise be the progressive movement of traffic (FHWA 2009).
stop controlled. A warrant is generally intended to define when If one or both of the conditions is met for the pedestrian sig-
a treatment (in this case a signal) is justified. Warrants are not nal installation, further guidance on placement of the pedes-
requirements to place signals. trian traffic signal is provided:
· Traffic signals installed at traditional intersections or major
Midblock Crossings driveways should control the minor street or driveway traf-
and Conventional Intersections fic through actuated means and should include pedestrian
In the United States, the Manual of Uniform Traffic Control detection.
Devices (MUTCD) provides warrants for when traffic sig- · If the pedestrian signal is installed at a non-intersection
nals may be installed (FHWA 2009). There are a total of nine location, it should be installed no closer than 30 m (100 ft)
warrants, one of which deals with pedestrians. In the 2009 from the nearest side street or driveway controlled by stop
MUTCD, Warrant 4 (Pedestrian Volume) states that a traf- or yield signs and should also be pedestrian actuated. Rec-
fic signal "at an intersection or midblock crossing shall be ommendations are also provided for adequate sight dis-
considered if . . . one of the following criteria is met: tance, including removing obstructions within 100 ft of the
signal heads on each direction of the approach and equip-
· For each of any 4 hours of an average day, the plotted points ping with proper signage and pavement markings.
representing the vehicles per hour on the major street (total · If the pedestrian signal is installed within a signal system, the
of both approaches) and the corresponding pedestrians per traffic control signal should be coordinated appropriately.
Figure 3. Warrant 4, pedestrian four-hour volume (source: FHWA 2009).
OCR for page 18
18
Figure 4. Warrant 4, pedestrian peak hour (source: FHWA 2009).
Last, traffic signals may be justified outside the bounds of Specialized pedestrian signal applications such as the PHB
the aforementioned MUTCD guidance if the 15th-percentile [HAWK (high-intensity activated crosswalk)], Pelican, Puffin,
crossing speeds are less than the assumed 3.5 ft/s at all inter- and Toucan crossings (Fitzpatrick et al. 2006) have all been
sections. The MUTCD states that the pedestrian volume designed for midblock crossings. Installation of these devices
crossing the major street may be reduced as much as 50%. at roundabouts presents a unique set of challenges. In many
In looking at international literature, a variety of pedestrian- cases, such an installation would create conditions that are not
related signal warrants from the United Kingdom, Canada, and recommended by the MUTCD.
Australia were identified. In Canada, the national MUTCD and
an Ontario traffic manual provide pedestrian-based warrants · According to Section 4D.01 of the 2009 MUTCD, "Midblock
for the installation of full traffic signals (City of Hamilton crosswalks should not be signalized if they are located within
2005). Intersection pedestrian signals, or half signals, are also 30 m (100 ft) from side streets or driveways that are con-
used in some locations in Canada. Warrants and guidelines for trolled by stop signs or yield signs" (FHWA 2009). While not
these devices largely reside at the local level (or provincial level directly applicable to roundabouts, this suggests that prox-
in the case of British Columbia) and include measures such imity between a pedestrian signal and sign-controlled move-
as vehicular and pedestrian volumes, pedestrian delay, avail- ment may cause confusion.
able gaps, roadway geometry, sight distance, speed, pedestrian · According to Section 4D.13 of the 2009 MUTCD, signal
demographics, and distance to the nearest adjacent signal. heads should be located no closer than 40 ft and no farther
In the United Kingdom, pedestrian traffic signals at round- than 180 ft from the stop bar, except where the width of an
abouts are fairly common. The warrant for such a signal is intersecting roadway or other conditions makes it physi-
based on the formula PV2 > 108, where P = pedestrian volume cally impractical (FHWA 2009). The minimum distance is
per hour (average of peak 4 hours) and V = vehicle volume per necessary to ensure that the signal head is visible through
hour (average of peak 4 hours). Both sides of the splitter island the windshield of a car. At a typical roundabout, the cross-
must satisfy the criteria separately in order to meet the warrant walk is only 25 ft from the circulatory roadway. This would
(entry and exit volumes from roundabouts must be considered result in the stop bar being placed in the circulatory road-
separately) (Baranowski 2004). way to achieve proper signal head placement on the exit leg.
In Australia, some states have pedestrian-based warrants for · Section 4D.12 recommends that "at signalized midblock
full signals at intersections and midblock signals (Queensland crosswalks, at least one of the signal faces should be over the
2003, New South Wales 2008). These warrants are similar to traveled way for each approach." In this case, mast arms
U.S. warrants in that they are primarily based on traffic and would be needed for signalized crosswalks at roundabouts,
pedestrian volumes, with additional emphasis placed on avail- which would increase cost.
able crash information. Additional wording is added to include
warrants for signals that "cater mainly to persons with partic- In addition to the above sections, there is a general need to
ular disabilities" including disabled, aged, or hearing-impaired ensure that the signal indications on the roundabout entry do
pedestrians. not create confusion with the yield sign at the circulating lane.
