For some shoppers, a long wait in line at the supermarket may lead them to head out the door. And they don't always make the purchase somewhere else: They may just abandon it altogether.

When faced with a long queue, the majority of US grocery shoppers will head toward the self-checkout lane (65%) or choose to shop during off-peak hours (53%) when a store is less likely to be crowded, according to an April 2018 Digimarc survey conducted by Forrester Consulting.

Others respondents said they willingly buy fewer items to take advantage of the express checkout lane or use scan-and-go technology to speed up the process.

Nearly one-third (32%) said they'll quit a long line and search for a better checkout experience elsewhere. But 11% said they will abandon a purchase entirely if a line is too long.

Many of the study's respondents viewed online grocery shopping as a decent way to skip checkout lines. That aligns with a variety of data suggesting that skipping lines is a key feature of online shopping. For example, a Retail Feedback Group survey found that consumers who buy groceries online do so because it saves them time (64%) and offers a more convenient experience than shopping in-store (52%).

However much people hate waiting in lines, online grocery buying remains on the margins, held back by consumers' preferences about touching, seeing and smelling the foods they purchase.

We forecast that only 2.8% of US food and beverage sales will occur online this year, and that percentage will not grow dramatically. By 2022, we estimate that 3.1% of US food and beverage sales will take place online.