At a recent show I picked up two packs of resin "Jersey Barriers" from the stand of The Sleeping Dragon Hobby Shop.
https://www.sleepingdragonhobbyshop.co.uk/They are not (at time of posting) on their web shop, but they have an email address (and a 'phone number) on the site.
Each pack contains four resin cast pieces from a 3D printed master. There are some obvious print lines and some artefacts, especially on the top surface. However it does provide them with some texture (more on that later).
They are much taller than Jersey Barriers (they are 20mm tall which is a metre plus at 28mm depending on your choice of scale).
After giving them a scrub, I sprayed the "visible" surfaces with Rustoleum Rust effect spray paint for some added texture before giving them an overall coat of Halfords Grey Primer. I then sprayed them from above with Halfords White Primer.
Half of each piece was then masked (you can see the artefacts on the top - they could be reinforcement).
And sprayed with Citadel Mephiston Red.
Once dry, they were extensively dry brushed with Citadel Terminatus Stone and washed with Citadel Nuln Oil.
They will provide suitable cover for infantry, even on slotted bases.
They will also provide cover for your vehicles.
But you will need to consider their placement if you do not want to provide cover for your enemies.
Caught in a spotlight, William Killian wishes he had cleaned the Land Rover before going out.
They are a nice addition to my scenery collection, and (at the time of purchase) notably cheaper than comparable barriers.