The programme of "nudges, reminders and prompts" were developed in collaboration with innovation consultancy Innovia Technology and are part of the brand’s ongoing campaign "When you drive, never drink".
The 20 prompts used included signs in various parts of the venues encouraging drivers to stay sober, making alcohol-free drinks more prominent, and providing special menus aimed at drivers.
The study took place over 23 to 25 May, which were compared to a control period of 16 to 18 May. 700 interviews were conducted with people leaving the bars, and data on drink sales were collected.
The bars with the greatest level of support for the measures saw a 50% reduction in drink-drive behaviour, Heineken said.
Heineken said the plan was for the programme to be rolled out globally, but that it would need to be adapted to be clutrally relevant to each given market. There is no firm timetable in place yet for doing this.
It is supported by a new TV ad, "No compromises", in which 2016 Formula One champion Nico Rosberg refuses to compromise on his principles in a number of ways – eventually turning down a beer because he’s driving. It follows a similar ad from 2016 featuring F1 veteran Jackie Stewart.
The new spot was created by Azeglio Bozzardi and Martino Lapini at Publicis Italy, and directed by Joachim Back through Stink London.
Rosberg also appears in a second video, alongside Stewart and David Coulthard, in which the trio take a "designated drivers’ pledge" – an online part of the campaign designed to help drivers publicly commit to staying sober. This was created by Poke.
Gianluca Di Tondo, senior global brand director for Heineken, said: "For our responsible drinking campaign to be effective, we looked long and hard to understand the root causes of the problem, and in 2017 we attained valuable insights by conducting a global study that uncovered the behavioural drink driving triggers.
"This insight has given us the opportunity to better target our marketing in order to reduce drink driving by developing a robust behavioural change programme and a new communications campaign, both with a clear commitment to drive real change.
"We are proud that our initial results are promising, but this is just the beginning of our journey. The next step in this campaign is to work in partnership with our markets as we aim to roll this out globally."