Of 151 drivers stopped by Thames Valley Police, 137 were using their phone.
The operation was carried out in Berkshire, Oxfordshire and Hampshire.
An unmarked lorry was used to spot offending motorists during a five-day period in 2016. Police said they were disappointed with the figures.
"Sadly we have seen many examples over the last 12 months of lives lost unnecessarily because a driver has not had their full attention on the road," Sgt Paul Diamond, who led the operation, said.
The joint operation with Hampshire Constabulary was carried out on the A34, M40, M4, M27 and M3.
In August last year, four people died on the A34 on the Oxfordshire/Berkshire border when a lorry driver, who was scrolling through music selections on his phone, smashed into stationary traffic.
The driver, Tomasz Kroker, was jailed for 10 years.

Following flooding at Brunton Park, Carlisle have three 'home' fixtures at neutral grounds and beat Notts County at Preston's Deepdale on Saturday.
Stanley's last two home games were postponed because of waterlogging.
"I'm really upset about how the league's handled the Carlisle affair," Coleman told BBC Radio Lancashire.
"We are now games behind Carlisle. We've had two postponements and they've been allowed to play elsewhere and I don't think it's right or fair.
"I don't think it's fair on the rest of the 23 teams who have to go to Carlisle when some teams won't have to go there.
"I just don't think it's anywhere near any shape or form fair.
"I've got nothing against Carlisle, I wish them all the best in their ventures and what they do, but it's shifting the rules.
"I've got every sympathy for the people that have lost belongings and homes, I'm not decrying any of that - I'm just saying strictly from a football point of view it's an unfair advantage to play at another ground."
The Cumbrians will also play upcoming matches at Blackburn's Ewood Park and Blackpool's Bloomfield Road.
A van driver eating breakfast cereal on the M27 and an HGV driver shaving behind the wheel on the M4 were spotted by police in a crackdown on distracted motorists.
[NEXT_CONCEPT]
Accrington Stanley manager John Coleman has criticised the Football League for allowing Carlisle United to move their home games because of flooding.