MONTREAL -- From CTV Montreal’s second-floor perch at the corner of Papineau and Rene-Levesque, as night fell on the city, staff noticed something peculiar about the Jacques-Cartier Bridge: it was dimmer than before. 

And this has been true for several days now.

“People may not realize it, but the illumination of the Jacques-Cartier Bridge is not turned on by the flick of a switch,” said Nathalie Lessard, the spokesperson for the Crown corporation that manages the Jacques Cartier and the Champlain bridges. 

The animated lights of the bridge are affected by collected social media data, traffic and weather, which the Crown corporation refers to on its website as the city’s “mood.“

The lights first graced the bridge in May, 2017 and were unveiled during the city's 375th anniversary celebrations, coming in at a cost of $40 million. The display was designed by several companies, including multimedia entertainment specialists Moment Factory. Marie-Pier Veilleux, a spokesperson for the company explained that one reason the lights may seem dimmer now is that the 365 different colours used are seasonal and the dominant shade in winter is blue. 

The bridge also reacts to “urban data” and real-time social media mentions of Montreal. During a regular festival season, for instance, the activity on the Internet drives a vibrant light display. But with festivals off the calendar for the time being, that input is reduced. 

“Right now the mood of the city is a bit low,” Lessard said. “It’s quiet, there’s not a lot going on.” Traffic on the bridge — which is much reduced after curfew — also plays a part.

“Of course if there’s less traffic on the bridge, there will be less light for the show,” Veilleux said. 

The colours of those lights also reflect certain “dominant themes in the media” — green for the environment, aqua for technology, yellow for business, blue for sports, pink for institutions such as politics or religion, red for civil society and purple for the arts. Montrealers are also encouraged to use the hashtag #illuminationMTL to goose the light display. 

According to Lessard, “It’s a surprise to see that it is so affected by the curfew. It’s a sort of an unintended side effect.” She pointed out that also shows something profound about the design of such an elaborately conceived public display:

“It’s really the proof that the Jacques Cartier Bridge is connected.”