Anne McMenigall and Claire Wallace's husbands, Andrew McMenigall and Toby Wallace, died after being mown down by 32-year-old Robert Palmer's lorry in Newquay, Cornwall, on July 2 last year.
Mr McMenigall, 47, from Craigleith, Edinburgh, and Mr Wallace, 36, of Hawick, were taking part in 960-mile ride from Land's End to John O'Groats.
They were raising money in aid of a trust named after a former colleague at the firm where they worked, Aberdeen Asset Management, who died from cancer and a charity that supports children and their families with the disease.
After Palmer was jailed at Truro Crown Court yesterday, the women criticised UK transport laws as too "lenient", with charges against individuals difficult to attain, and claimed resources for dealing with traffic offences were being cut back.
They said in a statement: "There are no words to describe the devastation and loss we, and both our families, feel following the deaths of our husbands. They were exceptional and giant men in every sense of the word.
"It is a tragedy so many other families are also mourning loved ones who have been killed on Britain's roads, particularly when many of these deaths were completely avoidable.
"So many of these families do not ever see a sentence brought against the person who killed their husband, their child, their brother, their father."
It added: "Transport laws are lenient, charges are difficult and onerous to attain, and less and less resource is being dedicated to road traffic collisions."
Mr McMenigall was a senior investment manager with Aberdeen Asset Management.
He had two children, Jennifer, 15, and Lucy, 12, one of whom had recovered from cancer.
Cambridge graduate Mr Wallace was a senior relationship manager with the company in Philadelphia and had previously rowed the Atlantic in aid of charity. Both were keen cyclists and were wearing reflective gear and riding in single file when they were fatally struck.
Palmer, of Bude, Cornwall, had previously pleaded guilty to two charges of causing death by dangerous driving on the A30. He also admitted a further charge of dangerous driving in relation to a second similar crash 10 weeks later on the same road.
At the time of the fatal crash Palmer - a night time delivery driver for Frys Logistics Ltd in Launceston - had little sleep because instead of resting during the day he was working on vehicle maintenance for the firm. He was also habitually using his phone to send text messages while making deliveries for discount store Lidl.
Sally Moore, lawyer for the victim's families, said: "It seems incredible this man was ever let behind the wheel of any vehicle, never mind a heavy goods vehicle."
Sentencing, Judge Christopher Harvey Clark, QC, told Palmer: "You had almost certainly fallen asleep but it is equally clear you were disregarding the rules of the road by texting continuously and it would seem at length.
"You completely ignored their presence on the road ... you mowed them down.
"It is clear that at the time when this tragic accident occurred you were suffering from extreme fatigue and exhaustion."
He said Palmer should not have been on the road and it was his responsibility to take sufficient rests. The judge added: "All the indications are that long before the fatal collision you must or should have been aware of your condition.
"It is also clear - although I accept not a primary cause of the accident - you had been inappropriately and illegally using your mobile."
The judge said both Mr McMenigall and Mr Wallace were "fine and good men" who were very successful in their careers and personal lives. He said the fundraisers were the kind of people "who make this world a better place."
He added: "They met their deaths as a result of your criminal actions. I recognise the terrible loss to their families and friends. They cannot be replaced."