Massachusetts commuters might catch a glimpse of the future out their car windows on Monday: the state’s first billboard ads for a marijuana dispensary.

New England Treatment Access, or NETA, which operates medical marijuana dispensaries in Brookline and Northampton, has purchased space on four billboards: two on the Massachusetts Turnpike near Exit 5 in Chicopee, one on Route 28 in Somerville, and another near the Mass. Ave. exit off Interstate 93 in Boston.

The ads are simple: set against a bright green background, they read, “Why wait for better health?,’’ and carry NETA’s Web address.