Sussex Police said in the last five years, it has only fined one person for breaking the 20mph speed limit in Brighton and Hove.
The penalty was handed out to the unlucky driver in June last year - making them the only person to have been stung since the 20mph zone was introduced in Brighton city centre.
Sussex Police say it is the only fine they have issued since the reduced limit was first introduced in 2013.
But residents on social media have labelled the news as 'farcical' and say many drivers do break the limit, but there is a lack of police enforcement.
Brighton and Hove City Council admitted the limit was not routinely enforced back in 2015.
East Sussex also has 20mph zones in Lewes, Kingston, Seaford, Hastings and Stone Cross.
The traffic calming measure is meant to be safer if there is an accident, and Facebook users have called on Sussex Police to be stricter with those who break the limit.
Paul Hutchings, who requested the information from the police force, said: "The 20mph limits are routinely flouted and according to an Sussex Police FOI request, just one person has been fined for breaking them since they were introduced nearly 6 years ago.
"That's farcical. These limits will make our city safer and improve our quality of life. If drivers can't police themselves we need law enforcement to do the job for them."
But others backed the speed limit being only lightly policed, commenting that there were more important crimes in the country officers had to focus on.
Nigel Slade commented: "20mph speed limits are not enforceable by the police. They are a local bylaw and therefore do not trump the Road Traffic Act.
"Police have better things to do than enforce 20mph speed guides."
And Joy Flowers said: "They don't have enough man power to police real crime, so expecting them to monitor random 20mph rules won't happen."
Caroline Penn, a former local councillor said: "They simply do not have the resources for the enforcement.
"The average speed in the city is around 25mph, so not a significant difference.
"However there are places particularly where roads are difficult to cross or near schools where enforcement would be welcome.
"It is a matter for the police, so there is very little they can do in terms of enforcement."