In a challenging market, out-of-home (OOH) ad spend is climbing in the UK, although the gains are small. eMarketer estimates total UK OOH ad expenditures will edge up just 1.4% in 2017.

“That’s overall spend. Digital is a different story,” said eMarketer senior analyst Bill Fisher, author of a new report, “UK Digital Out-of-Home Advertising: Growing Revenues and Growing Potential.” eMarketer PRO subscribers can access the full report here. Nonsubscribers can purchase the report here.

GroupM’s latest forecast indicates UK digital out-of-home (DOOH) ad spend growth will top 20% this year, accounting for nearly half of the OOH market. That heady proportion comes from just 10% of physical assets in some cases, indicating the sizable revenue potential for this medium.

The huge reach and impact of OOH is being supplemented by digital assets—this isn’t a digital vs. traditional debate. Such assets offer greater levels of flexibility, allowing for more precise campaign timings and durations, and are also helping to bring “activation” to what has traditionally been a branding tool. Localized DOOH campaigns have been proven to spur uplifts in smartphone brand actions, for example.

In the latest episode of "Behind the Numbers," eMarketer senior analyst Bill Fisher talks about how the UK is blazing the trail for digital out-of-home advertising. This episode is made possible by Criteo.