Motorists spent €158m on paying tolls for using the M50 last year, latest figures show.
As many as 150,650 vehicles a day were using the Dublin motorway on average, up 4pc on the year before.
54.9 million vehicles went through the M50 electronic toll gates last year, the 2019 annual report for Transport Infrastructure Ireland (TII) revealed.
The report said there has been annual rates of growth in the numbers of vehicles on the M50 since 2010.Congestion
"The rate of growth is expected to decline over the short to medium term due to the build up of congestion," it said. The problem was also on surrounding roads.
There were 1,161 incidents on the M50 including 525 crashes. It said the M50 is busiest on a Thursday.
The report also revealed €9m of the €158m toll income arose from penalties. Last year there was a compliance rate of 97.6pc in paying M50 tolls, up 0.3pc on 2018, the report said.
The cost of operating the M50 toll in 2019 was €52m.
TII also oversees the Luas and, according to the annual report, "since March 2020 revenues from M50 eFlow and Luas operations and other roads and public transport services have reduced significantly".
"For the full year 2020, the Covid-19 pandemic will cause significant reductions in revenues within our commercial operations but the exact impact in 2020 and thereafter cannot be accurately predicted," it said.
The report said toll income for the Dublin Port tunnel last year increased by 5% to €22m where total traffic was around 8.8m trips.
The tunnel had an annual increase of 4% in traffic compared to 2018, bringing average weekday traffic to almost 24,000 vehicles per day.
About the Luas, the report said passenger journeys on the trams totalled 48.3 million, an increase of 15.6% on 2018 levels.
It states: "Passenger numbers on the Green Line went up 21.5% to 24.3 million largely attributable to growth on the Luas Cross City."
TII's total income last year amounted to €1.34bn including State grants of €1.119bn. Its expenditure amounted to €1.23bn, leaving a surplus of €81.24m after interest payments.
The accounts show TII chief executive Michael Nolan last year was paid €183,000.
Numbers of staff earning over €100,000 at TII last year increased from 37 to 39.