The Open Accessible Pedestrian Signals (Open APS) project seeks to address the Call for Innovation - Enhancing Mobility for Blind and Low Vision Pedestrians challenge. We provide free and open tools for generating the hardware and software assets needed to produce accessible pedestrian signals (APS) at a dramatically lower cost than the existing solution, with more features.
As of December 31, 2016, there are APS units installed at 209 intersections citywide, 78 of which were installed over the past year.
Between 2012-2016, NYC added roughly 25 accessible intersections per year. In 2016, the city committed to increasing this to 75 accessible intersections per year. While we applaud this rollout, blind and low vision people deserve a more widespread accessible solution sooner. Price has been a significant limiting factor; each intersection costs about $43,000. Learn more about NYC APS Intersections.
We demonstrate a working prototype that provides APS with greater functionality than the current implementation, at a much lower cost. Our approach leverages open city data, commodity consumer tools, and an open-source approach to enable a broader deployment of APS at city intersections, giving greater accessibility for people who are blind and low-vision.
Existing NYC APS Solution
The current APS solution is a sign box installed parallel to each crosswalk. The box emits a chirp, so it is discoverable; when pressed, it will say “wait” if the crosswalk sign is not green; and emits a recognizable sound during the duration the crosswalk is green.
The existing APS solution does not provide wayfinding guidance. There is no speech announcement of what intersection a person is at. Also, there is no support for low-vision people to more easily read street names.
The current cost per intersection averages approximately $43,060. For the 78 intersections where APS was installed in New York City, the total cost was $3,358,690.
- The baseline estimated cost to furnish and install an APS unit on an existing pole is $985.
- A typical quadrant intersection will need eight units, meaning that the estimated cost per intersection is at least $7,880. In many instances, an intersection may require additional work that increases the cost of the installation.
Proposal: Open APS
We propose a more advanced set of functionality at a fraction of the price. Our devices are customized to each intersection and crosswalk, giving specific signage and audio guidance. To make this cost-effective and feasible, we will automate the creation of the signage and audio content using city public records data; and we will generate these assets free of cost.
Two modes: full crosswalk guidance, or orientation-only
Our solution is built to support two modes:
- Full crosswalk guidance: we are connected to the crosswalk light status (walk, changing, don’t walk) and can give guidance on whether it is safe to cross.
- Orientation-only: we provide location and orientation information, but do not give crosswalk guidance
The full crosswalk guidance mode is enabled when the device is connected to the crosswalk light signal (hardwired connection). We can give guidance on the light status (via LED lights, voice, and haptic feedback). While this is a much better pedestrian experience, it may incur significantly higher installation costs.
The orientation-only mode is our fall-back state. The APS gives tactile wayfinding guidance, and when pressed gives audio instructions about the location, hazards, and orientation; but we will not be able to provide guidance for when it is safe to cross. Devices may be installed in orientation-only mode in locations where it is too expensive to connect to the traffic signal; and if power goes out, the device can continue to operate off a backup battery in orientation-only mode.
- Prominent display of street name, in both large reflective font and braille
- Tactile direction arrow
- Walk / Don’t Walk LED lights are visible to near-sighted people, or if intersection is blocked. (Note that we use white-red LEDs instead of green-red LEDs to avoid colorblind confusion).
Our APS emits different chirp sounds to indicate walk / don’t-walk.
The sign is a large button that speaks when pressed:
- Announce street being crossed
- Give light information (wait, or OK to walk)
Longer presses are used to request more in-depth information:
- Crossing safety: crosswalk length, bike lane, medians, and hazards.
- Location: cross-street, and bearing.
Example long-press audio for don’t-walk:
Transcript: “Wait to cross W 23rd St at 7th Avenue, Wait the Cross Walk is 52 feet long and goes South-West”
Our prototype’s total cost of goods (COGs) was $66. Our open solution does not have any licensing or annual fees. Therefore, at our current COGs, building 8 APS boxes for a 4-way intersection would cost about $528.
Note that at scale, these COGs would be significantly lower; and also, the enclosure and electronics would almost certainly be mass-produced, further lowering the cost.
Like the existing APS installations, our solution will need power (~3 watts) and a hardwired connection to the crossing signal state (while timing can be predicted, it’s a safety issue to avoid e.g. maintenance changes or clock skew). We do not require internet connectivity; the devices work offline.
Compared to the current NYC APS solution, our proposal has a number of benefits:
- Improved safety: We give more detailed crossing information to call out potential hazards
- Improved wayfinding Low-vision and blind people can much more easily learn where they are, with details about their bearing and cross-street
- Lower cost means larger deployment: A budget of $591k/year could purchase 1120 intersections using our solution (1120 intersections * $528/intersection), compared with 75 intersections using the current technology (75 intersections * $7880 per intersection).