If you think it's dangerous to be a pedestrian in construction zones such as those on 6th Street in downtown Minneapolis, where sidewalks are blocked and rerouted, consider how difficult they are for people who cannot see.

A new smartphone application currently in development by the University of Minnesota Traffic Observatory in partnership with the Minnesota Department of Transportation could help make it safer for pedestrians who are blind or have poor vision. It could alert users to construction hazards and give instructions on how to navigate around them.

The application, which does not yet have a name, works like this. A Bluetooth beacon is attached to a sign, post or barricade in a construction zone and sends the information to a GPS receiver on the user's smartphone. (GPS receivers have become a standard feature on mobiles and smartphones.) When a work zone is detected, the user's smartphone picks up the sensor, vibrates and sends a corresponding audio message. The user can tap the phone to have the information repeated.

Researcher Chen-fu Liao has run a number of tests at the busy intersection of Hwy. 13 and Parkwood Drive in Burnsville. There, by pointing the phone north, Liao gets information that tells him to "wait for walk signal," how many lanes the highway has, that there is a center island separating the lanes and how long he has to cross once he has a walk signal. Point the phone west to cross Parkwood, and he gets a different set of instructions.

On 6th Street, for example, messages could be programmed to tell him that a sidewalk is torn up or closed ahead and to use one on the opposite side of the street.

"The application will help the visually impaired with work-zone routing or information about the intersection — a point-to-point personal solution," Liao said when he recently gave The Drive a demonstration.

The plan is to install the technology at every work zone, Liao said.

On average from 2002 to 2006, about 15 percent of fatalities resulting from crashes in work zones involved pedestrians, workers and bicyclists, according to federal data. The Americans with Disabilities Act (ADA) requires that pedestrians with physical and/or mental disabilities be accommodated during construction. The federal government strongly encourages states to provide either audible warnings or tactile maps at work zones for visually impaired pedestrians.

The application is still in the testing phase, but Liao said it is already garnering some interest from the U.S. Department of Transportation, and it could become an ADA requirement if the demonstration proves useful.

He said the app won't be rolled out for several months, as researchers conduct more testing with visually impaired users and evaluate its effectiveness. Researchers also are gathering information on traffic-signal timing.

It's likely that users would be able to access the application without paying a monthly fee, Liao said.

Initially, the application will be geared for construction zones, but future improvements could incorporate information about transit or other hazards such as having to cross light-rail tracks.

To see how the application works, check out the video on startribune.com/video.