At least 22 cyclists broke the new road rules, but none was apprehended in a sample 30-minute period on the first day fines were introduced, the Herald has discovered.
The fixed-charge fines, which were introduced on Friday - for offences including cycling through red lights, cycling on paths and cycling in darkness without front and rear lamps - will see cyclists hit with a €40 on-the-spot fine if they are caught.
However, the controversial cycling fines could be impossible to enforce, according to a Dublin City Councillor.
Independent Cllr Gary Gannon said he doesn't expect that gardai will be able to cope with the extra workload.
A sample survey of cyclists committing offences was conducted by the Herald on a busy Dublin street, with 22 rule breakers spotted in the space of 30 minutes.
The sample, overseen on Friday, July 31, on College Green, took place between 6pm and 6.30pm and saw 19 cyclists going through red lights, with three others cycling on paths.
If each of these offences were penalised, €880 worth of fines would have been issued.
Councillor Gannon, who is a cyclist himself, told the Herald that he wasn't surprised by the results of the survey.
"I don't know realistically how they're going to be enforced," said Mr Gannon.
"If it's a case where we're just expecting the gardai to increase their workload, then it's not going to work. If that is the case, then you'd have to be very unlucky to get pulled up on it."
Some 12 cyclists were killed on Irish roads in 2014, seven more than in 2013, and Cllr Gannon thinks the fixed charge offences could make cyclists more aware of the rules of the road.
"If it can make people more aware, then it can't be a bad thing," he said.
"If we can get some sort of order there it'll certainly be beneficial for us as a city, because, to be honest, I've been a cyclist for the past couple of years and I don't know any of the rules, but have never really been stopped."
Fines will be sent to the address provided by the cyclist at the time and will increase to €60 if not paid within 28 days, €80 after 56 days and if the fine is still not paid, a court order will be issued.
No figures are held by gardai on the number of offences over the first weekend the bye-laws have been in place, and are not to be made available for another two weeks.