Functioning of pedestrian signals
Red man, green man symbol
Pedestrian Signal Timing
Length of the WALK interval varies by time of day. WALK interval usually calculated using a walking speed formula of 1.3 meters per second, but up to 1.5 meters per second can be used.
No flashing clearance interval
Fixed timed signals in most of central business district
Streets typically were narrow (by US standards) with a great deal of pedestrian and bicycle traffic. Streets included wide bike lanes, often slightly raised from the street level.
No unsignalized right turn lanes for cars, but there are right turn lanes for bicycles.
Curbs are typically 3–4 cm high, which is said to be acceptable to persons with mobility impairments.
Detectable warning surfaces installed in some locations at the curb, usually in a one-foot band. No detectable warnings at edges of cut-through medians.
Number of APS
Figure 10-15. The tactile arrow on the APS in Denmark was on top of the device which was located on a pole near the crosswalk line. Most intersections were pretimed so no pushbutton was included on this device.
Very common in central business districts; outside of central business districts APS are installed at the request of the Danish Blind Association and only at requested crosswalks of the intersections.
Most installations have audible signals coming from devices at pushbutton height, whether they have pushbuttons or the signals are fixed timed; overhead beaconing speaker devices are currently installed in combination with pushbutton locator tones at a few trial locations.
Signals must conform to a national standard.
Locator tone and WALK indication
- Both are 880 Hz square or saw-tooth wave tones. Locator tone is pulsed at 30/minute and WALK indication pulsed faster.
- The Danish standard requires that the WALK indication be five times the rate of the locator tone.
- The pulse length of the locator tone is 400 ms and the pulse length of the WALK tone is 200 ms.
- All APS respond to ambient sound, unless special permission is received to set the signal to a constant low level.
- Although the standard for setting the volume is that the signal should be audible 3 meters from the pole, the signal was quite often audible as far as 10 meters from the pole.
- The installer determines volume by listening.
- Located consistently at the end of the crosswalk line so locator tone could be used to line up for crossing.
- Consistency of location is considered very important; the APS is installed no more than 0.6 meter from the curb line and the horizontal distance from the crosswalk line is not more than 0.3 m.
- Stub poles are installed if signal poles are not available in the appropriate location.
Figure 10-16. Danish APS with tactile bar (arrow) mounted on the top. The bar is aligned with the crosswalk, and two knobs at the end of the bar indicate a median and the far side of the street.
- A knob on the end of the bar indicates the far side of the street and additional knobs indicate the number of islands or medians that will be encountered prior to the far side.
- All APS devices have a bar aligned with the crosswalk, functioning as an arrow, on top of the device.
- Where there is a pushbutton, it is usually located on the backside of the APS, toward the pole, with sufficient space for fingers to reach between the APS and the pole.
- In general there is no need to push a button, as most intersections have pre-timed pedestrian phases.
Locator tone was same tone as the WALK interval tone, and at the same intensity. Repetition rates at some locations in Copenhagen did not seem to conform to the published standard.
At a multi-leg intersection, the APS were very usable for crossing and alignment.
- APS were very consistently located in relation to the crosswalk.
- Directional bar (arrow) was useful, as were crosswalk maps on the side of the signals.
- Medians were cut-through, without detectable warnings, but the sound of the APS on the median gave some information about the median location.
The representative of the Danish Blind Association mentioned concerns of some people that the signals were too loud, causing noise pollution.
Mohammed Abazza, Traffic Engineer, Copenhagen
Neils Christian Johanneson, Siemens
Inge Kyhl, Orientation and Mobility Specialist, Institute for the Blind and Partially Sighted in Denmark
Mehta Rohe, Danish Blind Association
Jørn Vammen, Signals Engineer, Danish Department of Transportation
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