EXCLUSIVE: THEA testing for V2X interference in 5.9GHz band


The Tampa Hillsborough Expressway Authority (THEA) is undertaking new testing for interference in the 5.9GHz transportation communications safety band, following the announcement last year that unlicensed wi-fi will be allowed to operate in the lower half of the spectrum.

Speaking exclusively in the latest edition of the TTI podcast, THEA innovation director Bob Frey, who helps oversee the USDOT’s Connected Vehicle Pilot in Florida, explained that, while the transition from DSRC communications protocol to C-V2X, also mandated in last year’s Federal Communications Committee (FCC) ruling, was likely to progress smoothly, there was more concern about potential for interference if the available spectrum is narrowed.

Frey revealed that as part of the fourth phase (CV4) of the pilot in Tampa, Florida – which leads directly on from the first three phases: planning, deployment and data collection – testing is being undertaken specifically aimed at identifying potentially dangerous interference from unlicensed wi-fi. Although it should be noted that ITS America and AASHTO are still advocating for the spectrum to be preserved.

“We are actually installing a signal generator, and we’re going to do some testing on the impacts of different signals on real-time safety applications,” says Frey. “We’re interested in red-light violations and wrong-way warnings, that drivers are going to rely on. These have to happen extremely quickly to be useful. As opposed to traffic information systems, which you have a little more time on. They might tell you there’s a crash up ahead and you need to take a different route – that gives us a little more time on getting that information out.

“But the real-time safety ones are where we need to be wary of interference – we need to make sure that we’re putting these out there, that they’re safe and they work, and that the public can count on them as traffic safety management, similar to what we do with signals.”

You can hear the full interview with Bob Frey in Episode 11 of the TTI Podcast.



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Tom has edited Traffic Technology International (TTi) magazine and its Traffic Technology Today website since May 2014. During his time at the title, he has interviewed some of the top transportation chiefs at public agencies around the world as well as CEOs of leading multinationals and ground-breaking start-ups. Tom's earlier career saw him working on some the UK's leading consumer magazine titles. He has a law degree from the London School of Economics (LSE).