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.
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.