Dublin City Council needs better ways to control traffic than plastic bollards 'popping up like weeds'.
Trinity College Dublin Professor of Transportation Brian Caulfield has said while something is needed to protect cyclists and pedestrians, plastic bollards don't work.
He told The Pat Kenny Show the City Council needs to be more creative.
"There are other ways in which it's been done in other European cities," he said.
"But the fact is they're a necessity because of the mixed use we have in our cities; and also because of the proximity of cars to pedestrians and cyclists.
"A lot of the bollards have popped up like weeds - like the plastic ones for the cycle lanes - they're not aesthetically pleasing.
"I do think the city council needs to look at other examples across Europe, and across the world, of better ways to do that."
Prof Caulfield said one example of a better system can be seen in Italy.
"There's a couple of Italian cities that do it very well," he said.
"What some of them tend to use are hydraulic bollards, the bollards that are there to allow traffic in and out and to allow freight deliveries.
"More generically, the things that I've seen is where you use trees instead of bollards, also planters instead of bollards as well - again bringing more biodiversity back into the city.
"One example as well that I saw is where bollards are multi-functional: they're equipped with bike parking.
"There's a large lack of bike parking in the city, and it could be used with that."
'How we can do it better'
Prof Caulfield said we need to start removing the plastic bollards, some of which are cracked or damaged.
"A lot of the bollards, and a lot of the design we've done for our city, at the moment in terms of the streetscape has happened pre and post-COVID," he said.
"Everything happened pretty quickly, so I think it's perhaps a time now where we look back at what we've done and see how we can do it better."
Prof Caulfield said people who live in Dublin should be asked what they want.
"The City Council is great for engaging with the citizens of the city, and why not ask them what they want them to look like - have design competitions - that type of thing.
"While we have big, heavy, metal vehicles driving very close to humans we need something, so let's try and make it aesthetically pleasing but obviously as safe as possible too," he added.