Just 44% of drivers convicted of killing cyclists go to jail and more than a quarter do not even receive driving bans, a report by the BBC has found.
Figures obtained from all 45 police forces across the UK show that just 148 people have been charged with killing a cyclist in the last seven years.
In 2013 alone, 109 cyclists were killed on UK roads and more than 3,000 were seriously injured.
Of the 108 drivers found guilty of killing a cyclist between 2007-14, just 47 went to prison.
Those who ended up in jail served an average sentence of less than two years, while the average length of driving ban was 22 months.
For 26% of drivers found guilty of killing a cyclist, no ban was imposed.
George Holland's father died after being hit by a driver while cycling on a country road. Holland told the BBC his family has not received justice after the driver at fault received 200 hours community service, an £80 fine and an 18-month driving ban.
"[The driver] drove straight into the back of him and snapped his neck and he died instantly", Holland said.
British Cycling, which governs the sport in the UK, is campaigning for tougher bans and longer prison sentences for serious offenders.
"Our legal system doesn't support fully enough the more vulnerable road user and it doesn't reflect the responsibility people have when they drive a car", said former Olympic cyclist Chris Boardman, policy advisor for British Cycling.
But a spokesperson for the AA, Lorna Lee, defended current legislation by saying: "The courts already have a wide range of sentences that they can give to drivers who kill cyclists."