A team commandeered a regular service bus to spy on a city's drivers from above in what is thought to be the first scheme of its kind in the country.
From their vantage point they could look down into cars and see motorists on their mobile phones or committing other traffic offences.
They alerted colleagues in waiting patrol cars or motorbikes to the offenders who were then pulled over.
Police are using a double-decker bus to catch law-breaking motorists
One motorist was spotted texting for ten seconds by one officer minutes after he boarded the top deck of the Citybus.
he double-decker bus is great to catch people looking down on their laps using phones
Andy Llewellyn – Police officer
The operation on Friday afternoon and all day Saturday in Plymouth, Devon resulted in more than 130 motorists being caught.
Of those, 39 were using a mobile phone, 36 were pulled over for not wearing a seat belt and two vehicles were seized for not having insurance.
A further 53 drivers were reported for speeding and two more were arrested for drug driving.
A team commandeered a regular service bus to spy on a city's drivers
Officers would alert colleagues in waiting patrol cars or motorbikes after seeing an offence
Pc Andy Llewellyn of Devon and Cornwall Police said: “The double-decker bus is great to catch people looking down on their laps using phones.
“This is a great example of how we can maximise policing resources by working closely with partner organisations in the community.“
The driver of one Range Rover was stopped for using his mobile phone while stationary in traffic – and had no idea he had been spotted from the bus top deck.
Pc Llewellyn added: “Careless and inconsiderate driving is something that people may not recognise as a fatal factor.
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“In Plymouth and across the force area we are looking to address this and the other driving behaviours in the fatal five to improve road safety awareness.”
Police plan to repeat the exercise and Citybus spokesman Mark Horide, said: “It's been very successful – we will be doing it again.
“We support any police initiative that addresses personal safety.
“Our drivers report back on a regular basis to say they see people on their mobile phones while driving. It's something we are fully aware of.”