Traffic lights are set to be rigged to go red for cars but green for buses - to make public transport more important that private drivers.
Buses in Swansea will be fitted with GPS to track their routes and tell the traffic lights to turn green.
But the move is likely to hold up other drivers travelling in other directions - as their lights suddenly go red.
The technology is being trialled in Swansea city centre to help get speed up their public transport.
Operator First Cymru says it hopes the move will encourage more passengers to use the service.
Managing director Justin Davies said: "We have the ability to know exactly where our vehicles are minute by minute as the day progresses
"As we collect that data, that's going to be transmitted into the local authority in Swansea.
"If a bus is running a little bit late, the traffic lights will change to favour the bus to enable its journey to be slightly speeded up and catch up the time.
"Where the bus is running normally the traffic light sequence will be absolutely as it is."
"Because we've got so much more information now than we've previously had, we're starting to see quite clearly where the timetables don't quite work or where the services aren't working as well as we want them to - the punctuality isn't where it needs to be.
"We need to go through the process of adjusting the timetables, work out where we need to take some time away from journeys or even add a bit of time in."
"Over the next six months, you'll see a step change in the quality of service being delivered."