The Justice Minister says Gardai have set up a working group to look at why half of speeding motorists dodged a recent court appearance.
Of almost 67,000 speeding cases listed over the past 22 months, around 31,000 were struck out for non-delivery of a summons.
Leitrim, Kildare, Laois, Kerry, Galway and Monaghan are among the worst counties affected.
Susan Gray from the PARC Road Safety Group says it's alarming to see so many motorists getting off: "The Minister of Justice has assured Deputy Tommy Brouin that her officials have asked for clarification from the court service and from the gardaí on why this figure is so high.
"The non service for summons of speeding… what is happening."