Traffic app Waze is asking UK users to tell it which petrol stations have fuel available, amid the UK's shortage of petrol at the pump.
Users of the app are receiving push notifications asking them to "help your community stay informed". This data is then plugged into the app's live map for others to see which stations are open. Similar measures have been criticised as fuelling panic buying and adding to the problem.
Many local Facebook groups and apps such as Nextdoor have been flooded in recent days with messages from people offering advice about which petrol stations have fuel.
Waze, a subsidiary of Google, said the feature to show fuel stocks was not new but the company "has made the decision to push 'notify users' to encourage its use".
"Fears of disruption to fuel supply have created bumper-to-bumper traffic at petrol stations," Waze UK manager Ru Roberts said.
"In some areas, speeds have slowed to as low as 3km/h (1.9mph) as drivers rushed to fill their cars."
The push notifications "will enable motorists to guide others to forecourts which have remaining supplies, saving unnecessary journeys to those which have already run out," he said.
Waze's app is most often used to crowdsource live traffic data, so it can tell users about sudden road closures and traffic jams.