The £4m project will see a simple traffic-light-like LED system on the dashboard to alert drivers as part of the existing GreenRoad driver safety and fuel efficiency system.
The GreenRoad system gives drivers instant feedback about their driving manoeuvres, encouraging smoother, safer, more fuel-efficient driving.
Stagecoach says it has been in discussions with GreenRoad over the past eight months on how to extend the telematics technology to further improve safety for its fleet - including 3,800 double-decker buses - around low bridges.
Data from Network Rail shows that there were 1714 railway bridge strikes across the country in the 2019-20 financial year. Most of these incidents involve heavy goods vehicles (HGVs), with between 40 and 50 a year related to buses.
As well as the potential for serious injuries, bridge strikes have significant financial and other costs for the country. On average, a single bridge strike costs more than £6,000 and in 2019-20 these incidents resulted in more than 7,800 hours of delays for rail passengers alone.
In Scotland, over 6,000 delay minutes were caused in total and the incidents cost £460,000 (mainly in compensation for operators).
The Carlisle Road bridge in Cleland is the most struck in Scotland - being hit 13 times in the 2019/20 financial year.
The intelligent GreenRoad system will use GPS vehicle location data and mapping services to alert the driver to nearby low bridges. If the technology determines that the bus is heading towards a low bridge, it will sound an in-cab alert, allowing a safe exit route that avoids the bridge.
Following a 16-week software development phase, the technology and associated speakers will be installed on Stagecoach buses across the country by summer 2021.
Stagecoach Chief Executive Martin Griffiths said: “Everything we do starts with safety: for our customers, our people, pedestrians and other road users.
"Buses are already one of the safest forms of travel.
"But every year we invest millions of pounds in training our professional driving team and new technology to make our public transport operations even safer.
“Our country’s infrastructure includes many railway bridges designed in an era before modern transport vehicles went on the road, creating a safety risk.
"We have been working for many months with GreenRoad to design this important Low Bridge Alert enhancement to their proven safety technology, and are now implementing it to bolster the extensive measures we already have in place.
"We look forward to delivering the benefits from our investment across the country.”
The initiative has been welcomed by Network Rail, which works with the Driver and Vehicle Standards Agency (DVSA), highways bodies, and road transport providers to help prevent bridge strikes.
Network Rail’s Chair, Sir Peter Hendy CBE, said: “Bridge strikes are an unnecessary burden on our railway.
"They pose serious safety risks, cause hours of delays for rail passengers and road users and swallow up public funds which should be used on upgrading and improving our network.
“I commend Stagecoach on taking the initiative with the roll-out of this technology and I hope to see other operators take a similar proactive approach to tackling the issue in the near future.”