Existing road memorials to victims of collisions will be exempt from new rules, Transport Infrastructure Ireland (TII) has confirmed.
TII and the Department of Transport's new policy for local authorities states memorials are not allowed on motorways, dual carriageways and roads with a speed limit over 60km/h.
However, TII's Head of Roads and Greenways Capital Programme told the Oireachtas Transport Committee that existing memorials will not be removed by TII or local authorities "out of respect".
Geraldine Fitzpatrick said the policy recommends that local authorities have their own rules for roadside memorials and also acknowledges existing memorials.
She said roadside memorials can present a risk for all road users.
Ms Fitzpatrick said parking around roadside memorials can present an "inherent risk", adding that vehicles parked on the "side of a high-speed around is a hazard in itself".
She said local authorities might look to find an appropriate public space for new roadside memorials.
TII's Chief Executive Lorcan O'Toole said there have been examples where roadside memorials have caused accidents and fatalities.
Chairperson of the Oireachtas Committee on Transport Michael Murphy said he only became aware of the policy when he read it on the front page of a newspaper last year.
The Fine Gael TD said roadside memorials are "expressions of grief" and raised concerns about bereaved families being left in the dark.
He said the new policy must strike the right balance between "safety, local discretion, and compassion".
Mr Murphy said he was acutely aware of the "distress" and confusion caused by the "lack of consultation".
A group representing people who have lost loved ones in fatal traffic collisions said the confirmation is "one less pain, worry".
PARC founder Susan Gray said: "It would have been soul destroying for families seeing their memorial being removed as they are a form of comfort for many.
"I feel sorry though for those in the future who will not be allowed to place a memorial plaque at the place where their loved one died."