Digital billboards are nothing new, but McDonald’s is stepping it up a notch in order to target hunger commuters stuck in evening traffic.

By day, the billboards in the UK will display a picture of a Big Mac but as traffic around the sign begins to build, it will switch to an image of the Golden Arches with the lines “Stuck in a jam? There’s a light at the end of the tunnel.”

“Simple, tantalizing, recognizable product shots stimulate the appetite during fast-flowing traffic, while longer contextual copy lines run during heavy, slow-moving traffic, acknowledging the delays to deliver a relevant and powerful call to action,” said Dan Dawson, chief technology officer at Grand Visual, the company behind the concept.

The billboard will be fed real-time data from Google Maps, which will allow it to determine the best time to switch images.