A newly released study of digital-billboard safety commissioned by the Association of State Highway and Transportation Officials surveys the research currently available, here and abroad, and presents a list of best practices for communities that plan to allow and regulate what the industry likes to call “variable message” signs. The nutgraf: San Antonio's digital-billboard policy is at best negligence, and at worst malfeasance.
That may sound like hyperbole, but no one but Clear Channel was pressuring our city council to approve digital billboards in 2007, when it adopted the 12-month pilot program, which gave Clear Channel and Lamar permission to erect up to 15 signs -- they might have waited for the federal safety study due out this year, or, for instance, this document.
Things we likely got wrong, making some of our highways more dangerous than they already were:
- Dwell time, the amount of time a message remains on the sign before the next one appears. Research shows that its best if dwell time is long enough that its likely drivers will see only one image change while the sign is in their view. Ours is very, very short.
- Placement. Among the worst places to erect digital signs are at busy interchanges or on- and off-ramps, where drivers must already deal with distractions and more challenging tasks. I'm thinking of the big Clear Channel digital billboard at the Highway 281/I-35/I-37 interchange.
The Current interviewed lead report author Jerry Wachtel yesterday (scroll down to the third QueQue item under that link) -- who has criticized the City's underfunded plans to study the safety of its own signs -- and a more detailed QueBlog post is headed your way tomorrow. In the meantime, if you like details, download the full survey yourself here. (It's a lengthy Word doc, fyi.)