Functioning of pedestrian signals
- A "red man, green man" signal is used
- Pedestrian signal timing
WALK or "green man" timing is figured based on walking time of 1 meter per second and is calculated to the center line of the intersection.
Flashing DONT WALK timing was reported to be based on a walking speed of 1 meter per second, however this timing seemed to average about 3 seconds regardless of the width of streets.
- Mr. Sugimoto at the Japanese National Police Agency (JPNA), which manages all intersections, stated that intersection timing always includes a pedestrian phase, and at locations with vehicular actuation, pedestrian buttons are provided to lengthen the phase and/or actuate an audible signal.
- Many intersections have pretimed signalization.
Streets are generally wide. Driving is on the left.
Even where there is a very wide median it is not considered or used as a pedestrian refuge.
Most intersections have pedestrian crosswalks; a fence is typically used where crossing is prohibited.
At areas with high levels of pedestrian traffic, there may be exclusive pedestrian phasing. Most intersections with exclusive pedestrian phasing have audible signals.
Japan has very few non-signalized turn lanes or pork chop type islands.
Tactile Walking Surface Indicators, such as 'dot tiles' (called detectable warnings in the US) are ubiquitous in urban areas and have been in use since the 1960s to indicate danger or a need to make a decision. Dot tiles are used in combination with "bar tiles", a directional surface. Together they provide a continuously demarcated route for pedestrians who are blind.
Figure 10-2. At this intersection a chain fence is used where crossing is prohibited, and bar tiles indicate a travel route
Number of APS
Japan has 170,000 signalized intersections. Of those, 10,570 intersections have APS.
There are a variety of APS systems, most with sound broadcast from the pedestrian signal head (pedhead). A number of melodies and tones are used to indicate the WALK interval. The tone or melody varies from municipality to municipality; each is allowed to choose its own. JPNA has also developed a receiver-based system called PICS.
- 7,978 intersections have cuckoo or chirp from the pedhead during the WALK interval
- 2,592 intersections have melodies from the pedhead during the WALK interval
- 300 intersections in 20 cities have an infrared APS system (PICS-A) compatible with the Smith-Kettlewell/Talking SignsÂ® standard as developed and evaluated under the direction of JPNA
Functioning of broadcast APS
- Most common sounds for a WALK interval.
- Alternating signal is now the recommended signal and costs a "trivial amount" more than non-alternating. Usually use birdcalls; and are beginning to install alternating signals with different sounds, (chirp and chirp-chirp) on different sides of the street, to improve beaconing.
- Variety of melodies broadcast into the intersection, with a change in melody during the clearance interval.
- Often quite loud; sometimes possible to hear the melody of one intersection from a block away
- Message was "Walk" and the street name in Japanese
- Speaker in the pedestrian signal head may be pointed straight down toward the pedestrian below.
- Some APS in Tokyo used increased repetition rate of cuckoo or chirp during the clearance interval
- Very few APS had locator tones at the pushbutton.
- APS may have a sound for the pedestrian clearance interval:
- Yokohama used sound like that of an emergency vehicle
- Fairly common in Tokyo to center the APS speaker over the crosswalk on mast arm extending from the pole
- APS sound is usually turned off at 8:00 pm because residents nearby are bothered by noise.
Functioning of PICS System
PICS system is being developed, evaluated and installed under the direction of JPNA.
- Communicates from an infrared transmitter called an "IR station," and short range radio transmitter installed at the intersection, to a receiver carried by pedestrians.
- There are two types of PICS systems.
PICS-A speech system
Figure 10-5. The PICS-A system is shown with four infrared transmitters mounted on a horizontal mast arm
PICS-A speech system provides pedestrian traffic signal information and location information for bus stops and public facilities through a speech message to visually impaired pedestrians. As the traveler approaches within 10 meters of the intersection where the PICS-A system is installed, an FM radio message is received by the hybrid radio/IR receiver in either a speech or vibration mode. The vibration alerts users to the presence of the transmitted signal. The speech message identifies the intersection. When pedestrians arrive at a corner and are within the crosswalk with the receiver aimed toward the infrared transmitter on the opposite corner, they receive IR-transmitted speech information about the status of the pedestrian signal. A third function extends the pedestrian phase when a button on the receiver is pushed.
PICS-B image system
The PICS-B image system extends green lights and provides route guidance and information about the surrounding area on a visual display to people with mobility or hearing impairments. Portable receivers (transceivers) are pointed at "IR stations" located near pedestrian traffic signals to extend the pedestrian signal timing, make emergency contacts, and obtain route guidance and information about the surrounding area. A visual display provides information to the pedestrians.
The authors found the variety of overhead speakers loudly broadcasting musical sounds or birdcalls to be confusing and distracting. Although these systems have been in use in Japan for about 40 years, there is growing concern in Japan about the noise pollution they cause.
The PICS-A system provided signal and directional guidance quite efficiently. Radio transmitted information was useful for general intersection information on approach. A large array of transmitters is required for this system, as shown in Figure 10-5.
- A head-mounted receiver has now been developed by Mitsubishi Precision Corp. Barlow and Bentzen used this receiver at one intersection and found it effective.
- The standard receiver is hand-held and can hang on a neck cord or be put in a pocket when not in use.
Sources of information
Kunio Kurachi, Mitsubishi Precision Co., Ltd, Tokyo
Takabun Nakamura, Okayama Prefectural University, Okayama
Hirohiko Ohkubo, Mitsubishi Precision Co., Ltd., Tokyo
Michiko Shimizu, Orientation and Mobility Specialist, Tokyo
Osamu Sueda, Rehabilitation Engineering Society of Japan and University of Tokushima
Mikio Sugimoto, National Police Agency, Government of Japan, Tokyo
Masaki Tauchi, Okayama Prefectural University, Okayama
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