These findings emerged from a study by the Outdoor Advertising Association of America (OAAA) which saw 1,837 smartphone users aged 18-64 record, via a smartphone eDiary, their location, mode of transport, media activity, purchase behaviour and emotional context every half hour over a seven-day period.
These efforts revealed that OOH media typically reached panellists in the hour prior to 43% of mobile shopping activity, ahead of TV (27%), AM/FM radio (12%) and print newspapers (3%).
They also reached participants in the hour before 32% of mobile search activity, outpacing TV (26%), AM/FM radio (9%); and print newspapers (2%).
The differences were less marked when it came to social media activity generally and brand-related social media activity specifically.
In the former case OOH media reached panellists in the hour prior to 28% of mobile social media activity, matched by TV (27%) in this instance, but ahead of AM/FM radio (8%) and newspapers (1%).
And for the latter, it reached participants in the hour before 34% of brand-related social media activity, again on par with TV (34%) and ahead of AM/FM radio (15%) and print newspapers (7%).
In all cases, the study reported, OOH media exposure was greater for transit/bulletins/street furniture than for place-based media.
It also found that OOH was more likely than other media to reach smartphone users in the hour prior to QSR visits and mall visits, and in the same half-hour as considering purchases in the automotive, fashion and apparel, and fast food categories.
"These media could potentially influence consumers' purchase decisions in these and presumably other categories," the OOOA argued.
Separately, the organisation reported 20th consecutive quarter of growth in OOH advertising revenues, which rose 4.7% in the first quarter compared to the same period a year earlier.
The fastest-growing advertising categories were government and politics (+11.5%), financial (+10.5%) and media and advertising (+9.4%).
Data sourced from OOOA; additional content by Warc staff