The excess money has been used for tunnel maintenance.
Dublin's Port Tunnel operators have earned over €90,000 from excess toll fees.
That's the figure since 2019 as motorists who don't have the correct change have overpaid.
Most toll booths don't have a person on hand to deliver change or coins.
Transport Infrastructure Ireland (TII) has kept the money for 'tunnel maintenance' and other works.
Dublin Tunnel will be closed Thursday 9th June - Full Closure - 22:00 - 05:00
For more information on upcoming closures please visit https://t.co/OZoEHSTJTw pic.twitter.com/fS36gFZraz— Dublin Tunnel (@DublinTunnel) June 6, 2022
Many toll users pay by card now or have a tag in their vehicle that automatically processes payments.
TII made €44,900 in 2019, €19,500 in 2020, €19,000 last year and €7,600 to the end of March this year.
The numbers have fallen over the last couple of years due to the Covid-19 pandemic.
With travel restrictions in place and fewer motorists on road, their excess intake has been lower.