A search engine that lets travelers find and book a stay in non-hotel lodgings, Tripping.com, has detected a burgeoning “budbnb” trend in Colorado.

San Francisco-based Tripping.com aggregates vacation rental listings from the likes of HomeAway, Booking.com, VRBO and other sites, and shows travelers the best prices on available lodgings. It currently lists about 8 million properties, according to founder and CEO Jen O’Neal.

About 3 million of the properties on its site are “instantly bookable.” That means users don’t have to spend days emailing back and forth with a vacation rental owner to arrange a transaction and a stay.

In states where cannabis is deemed legal for recreational use, vacation rental owners are increasingly using “420” and “420-friendly” as keywords to draw travelers, O’Neal observed.

Her data team detected an 86 percent increase in the use of the keywords “420” and “420-friendly” for Colorado-based listings from 2014 to 2015, when the state made recreational cannabis legal.

Colorado enacted a law in late 2012 that made the private and limited use and possession of marijuana legal for adults 21 years and older. The state established a system to regulate and tax sales of marijuana in late 2013. Legal pot sales commenced in the state in early 2014.

Tripping.com is monitoring different cannabis-related keywords in its listings, and weed-related searches to see how the travel and tourism market is impacted by marijuana’s legalization.