Figures were released on Monday.
Over 1,600 cars have been impounded from unaccompanied learner drivers since new legislation was introduced in December, according to the
RSA.
New figures also showed that 2,311 people have received penalty points and fines since the start of the year for not displaying their L plates.
The law states that learner drivers must be accompanied by a fully-licensed driver, who has had their license for at least two years.
On Monday, the RSA urged multiple learner permit holders, eligible to sit a driving test, or to apply for one without delay.
The average wait for a driving test across the country is now six weeks, as 83 new driver testers have been recruited since the start of 2018.
The RSA has also warned that the reduction in waiting times has meant that
some learner drivers are being caught off guard by how quickly they are being called for a test, and have not put in the necessary preparation.
Moyagh Murdock RSA CEO said: "While we have seen an 11% decrease in the number of people holding a fourth or more learner permit this year, it’s simply not enough.
"The practice of people continuing to drive on learner permits without ever taking a test is unacceptable and unnecessary in today’s circumstances, where the national average waiting time to take a test is just over six weeks. The Road Safety Authority, in consultation with the Department of Transport, Tourism and Sport, is considering options to address this issue.
"These options may include an increase in the cost of a permit; a decrease in the duration of a permit; a requirement to take mandatory lessons with an approved driving instructor or a requirement to take a driving test before another permit can be issued for a fifth and subsequent learner permit holder."
