DALLAS • There are many depictions of a future in which people have mastered the art of manipulating the opacity of glass.
The tinted world of tomorrow is coming and airports - mini-cities of steel, concrete and lots of glass - are interested.
In a test late last year, Dallas-Fort Worth International Airport outfitted one of its gates with a new type of "smart glass" that can adjust for sunlight exposure.
The test was designed to see if the product, called View Dynamic Glass, might improve passenger satisfaction along a small stretch of terminal real estate - specifically, gate seating at A28 and a burger restaurant's east-facing bar, one regularly torched by the Texas sun.
It turns out that a cooler, darker bar encourages an extra round or two. Alcohol sales soared 80 per cent in October, compared with the same period in 2016, the installation of electrochromatic glass being the only difference.
Alcohol contributed 17 per cent of the restaurant's total revenue in October 2017, compared with 9 per cent the previous month.
The lesson was clear: Remove heat and glare from a glass-ensconced bar and people will dally longer, spending more.
For years, airport executives have analysed the links between travellers' impressions and their spending, with terminal "dwell time" the critical link: People tend to hustle through New York's dreaded LaGuardia as rapidly as possible, while lingering in acclaimed venues such as those in Seoul, Singapore and Munich.
As the fourth-busiest airport in the United States, Dallas-Fort Worth could benefit from this dynamic, its officials concluded.
"We definitely see the impact," said Mr Casey Norton, a Dallas-Fort Worth Airport spokesman.
The restaurant had approached the airport about its lagging sales, he said, and "they hypothesised that it was too hot" for customers to stick around.
The glass used in Dallas is manufactured by View Inc, a 10-year-old Silicon Valley company that targets commercial offices, hospitals, higher-education facilities, airports and other places where customer satisfaction is a priority.
French materials giant Compagnie de Saint-Gobain SA has a similar electrochromatic product called SageGlass.
The technology works somewhat like the windows on a Boeing 787 Dreamliner; a button lowers or raises opacity.
"We spend 90 per cent of our time indoors," said Mr Rahul Bammi, View's chief business officer. "The things that really matter are light, air quality, temperature and sound. We impact at least three of those in a positive way."
The study at Dallas Fort-Worth, conducted by a Cornell University design professor, also found that surface temperatures on seats and carpeting near the new gate glass were 10 deg F to 15 deg F lower, boosting dwell time by 53 per cent over that at a nearby gate with regular glass. Spending around the cooler gate rose as well.
The additional revenue may come at exactly the right time for airports in the United States. The rapid adoption of ride-sharing services has dented parking revenues, a massive source of cash for airports.
Parking and ground transport accounts for about 40 per cent of North American airport revenues, while spending on food and beverages is the fastest-growing portion of their concessions business, according to the most recent survey by Airports Council International - North America.
Privately held View does not release any financial data, but said that it has provided glass for 400 projects since 2012.
San Francisco International Airport is spending US$3 million (S$393 million) for View's electrochromatic glass in the US$2.4-billion overhaul of Terminal 1.
In the coming weeks, Dallas-Forth Worth plans to solicit bids for about 500,000 sq ft of such glass to use in gate and concession areas with sun exposure.