Improving work-zone safety for visually impaired pedestrians

vision impaired pedestrianNavigating sidewalks and intersections affected by road construction can be challenging for all pedestrians, but it’s especially difficult for those who are blind or visually impaired.

To help these pedestrians find their way safely, University of Minnesota researchers have developed a smartphone app that can detect upcoming work zones and provide routing instructions. The project, funded by the Minnesota Department of Transportation (MnDOT), was led by senior systems engineer Chen-Fu Liao at the U’s Minnesota Traffic Observatory.

The app builds on a previously developed smartphone-based system that was designed to provide visually impaired pedestrians with geometric and signal timing information at signalized intersections. Funding for the original project, also led by Liao, was provided by the Intelligent Transportation Systems Institute.

As part of their work developing the new work-zone component, the researchers surveyed a group of visually impaired pedestrians. The goal was to better understand their challenges and the information that would be most helpful to them when approaching a work zone. Results provided the researchers with guidelines as they determined what the app would communicate to users. 

sidewalk closed signsThe app uses Bluetooth beacons—which can be attached to signs, posts, or construction barriers in a work zone—that communicate with the GPS receiver on a user’s smartphone. When a beacon is detected, the phone vibrates and provides an audio message. The message includes the pedestrian’s current location, the location of the work zone, and suggested routing instructions. The user can tap the smartphone to have the message repeated.

The federal government strongly encourages states to provide either audible warnings or tactile maps at work zones where visually impaired pedestrians will likely be affected.

“The smartphone application is a step in that direction,” says Ken Johnson, a work zone, pavement marking, and traffic devices engineer at MnDOT and the project’s technical liaison. “It’s a way to see if this type of wayfinding device would work.”

The researchers also integrated the work-zone component with the intersection crossing information provided by the previously developed system. If a Bluetooth beacon contains both work-zone and intersection information, the app provides the work-zone message followed by the intersection and traffic signal information, based on the direction the smartphone is pointing.

20.6 million Americans 18 and older report experiencing significant vision lossMoving forward, the researchers plan to work with MnDOT and local cities to access real-time traffic signal information and work-zone construction information on a larger scale. Prior to the release of the app, additional testing will also be conducted.

In addition, the research team has received funding from the Roadway Safety Institute (RSI) to expand the project by creating a “condition aware” infrastructure that can be integrated with the smartphone app. The goal is a system that can self-monitor and keep the information it broadcasts to app users as up-to-date as possible.

The project will include the development of Bluetooth devices that can be installed anywhere, such as on a light post at an intersection or on a construction barricade or traffic cone. These devices, which will be able to sense other devices within their range, will help create a local map of the environment. A database that contains the location and message of each device will be integrated with the smartphone app to provide navigation information to visually impaired pedestrians.

“This mapping methodology will ensure that correct audio information is provided to app users at the right location,” Liao says. “It could be used anywhere—at traffic intersections, skyways, or underground tunnels—to provide directions for travelers.”

The team expects the app to be available to the public following the completion of the RSI-funded project.


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