Case Study — Halifax, Nova Scotia
Date: April 2005
History and Background
Halifax has been using pedhead-mounted APS since 1998. Pushbutton-integrated units were introduced in 2003 and are now in operation at five intersections. The APS units were installed in response to requests from the Canadian National Institute for the Blind (CNIB). All installations were retrofits to existing signals and were performed by a contractor.
Process and Procedure
Requests for APS installations come from the CNIB which typically provides the city with a list of intersections where they would like APS installed. The city reviews the list and selects intersections for APS installations based on design of the intersection and available funding. If the intersection is suitable for pushbutton-integrated units, they install Novax Vibrawalks in addition to the overhead speaker. Factors that affect the decision about pushbuttons include suitability of pole location and availability of wiring.
APS in Halifax were funded by the capital budget in a specified fund for pedestrian safety issues. There was also a federal 50-50 funding match in 2004 for APS installations.
APS Type and Features
Pedhead-mounted and pushbutton-integrated devices from Novax Industries (DS2000 for overhead speaker units and Novax Vibrawalk for pushbutton)
APS features (at installations where pushbutton-integrated devices are installed):
- Vibrotactile WALK indication
- Audible WALK indication, only in response to an extended button press
- Pushbutton locator tone
- Tactile arrow
- Actuation indicator
- Automatic volume adjustment, in response to ambient sound
Figure 9-20. APS pushbutton mounted on wooden pole, showing conduit installed into the bottom of the pushbutton device
The APS speaker is mounted on top of the pedestrian head and faces across the street. A typical configuration for a crossing in Halifax involves two APS speakers, one at each end of the crossing. The volume is adjusted so the sound only reaches ¾ the way across the street, intended to enable the user to detect the second APS when part way across the street to guide them in the proper direction. Setups with only one APS per crossing generated numerous noise complaints as the volume has to be higher to be heard across the street.
Most APS are installed on aluminum poles but some locations have wooden poles, as shown in Figure 9-20. The overhead APS on wooden poles are clamped to the signal arm or pedestrian head. Novax pushbuttons typically are wired through the back of the device. To wire the pushbuttons, ½-inch PVC conduit is strapped to the wooden pole and an LB or liquid tight flex pipe runs a hole drilled into the bottom of the pushbutton.
The overhead speakers are typically mounted to the pedestrian signal head. When the APS speakers were mounted into plastic (polycarbonate) signal heads, strong winds would push on the speaker and crack off the thin plastic of the signal head into which the speaker was mounted. Where there were plastic pedestrian signal heads, the speaker was mounted on the pole or some other metal or wood surface, as shown in Figure 9-21. Pedestrian signal heads made of aluminum did not have this issue. In areas with less of a problem with strong winds, this may not be a concern.
Availability of wiring at the pole is an important issue. If sufficient wiring is installed with the signal, installing an APS later is much easier. Pulling wire later can become prohibitively expensive.
The city handles the maintenance of the devices. Being near the ocean, moisture and salt in the air is a problem, as is salt on the roads for de-icing. The overhead speakers generally start having problems at the 5-year mark, due to the salt and moisture. They usually last from 5 to 10 years. . The Vibrawalk pushbutton devices have not shown any problems during the two years they have been in service.
Cold Weather Issues
Snow is a constant problem in the Halifax climate. Snow banks can prevent access to the pushbuttons when not cleared properly. For intersections where pushbuttons are used, pole placement becomes an important issue so all pedestrians can reach the pushbutton. If pushbuttons are located to the immediate left or right of the crosswalk, there's a better chance of them being reached by pedestrians and having the snow cleared properly. Halifax uses mini-plows for clearing sidewalks. They anticipate that this could be a problem with stub poles (i.e., knocking them over), so the use of stub poles is generally avoided.
Other problems are caused by freezing temperatures. Pulling additional wire for a retrofit installation cannot be done in the winter due to ice in the wire conduits. Extreme cold can cause some signals cabinets to fail and thus the APS to fail.
The initial installations of pedhead-mounted APS installations were configured to give the audible WALK tone at every cycle. The city received complaints about noise, especially in the summer months when people had their windows open. Due to concerns about noise, these units were set to be off (give no audible indication) from 11:00 pm to 6:00 am. The pushbutton-integrated installations, as installed in Halifax, can be accessed 24 hours per day, providing the WALK indication only when the button is held for three seconds or more. No feedback was reported on the pushbutton-integrated devices.
Traffic Signal Supervisor
City of Halifax, Nova Scotia
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