A motorway authority in the UAE came back to us with a drawing, not a question. The section said “clear acrylic, 18 mm, aluminium-posted, EN 1793-2 tested” and every pre-bid phone call that week was about the same thing: getting a highway noise barrier acrylic panel that holds a real acoustic figure and a real impact rating, not a sales pitch.
Why thickness starts at 15mm on a highway
On a live motorway a barrier panel has two jobs that fight each other: it must stop enough traffic noise, and it must survive the impact of an errant vehicle. Below about 15 mm a clear acrylic sheet starts to flex and can transmit more low-frequency sound than it reflects; above about 25 mm it becomes heavy and expensive for the marginal gain. Most European and Middle-Eastern highway projects therefore specify clear acrylic between 15 mm and 25 mm, with 18-20 mm the common sweet spot for urban corridors.
A seven-line checklist before you order
- Nominal thickness and the tolerance you can live with.
- The acoustic standard (EN 1793-2, ISO 140 or local) and the dB figure the panel must meet.
- Impact / crash standard if the barrier sits on an elevated or high-risk stretch.
- UV stability requirement for the local sun load — cast acrylic holds clarity outdoors.
- Panel module width and how the sheet mounts in the post channel.
- Expansion allowance so panels do not bind in heat.
- Test documentation the authority will accept at tender.
For the acoustic test documents side of this, our guide on transparent noise barrier panel test report explains what to check, and the material trade-off sits in acrylic vs polycarbonate noise barrier.
Frequently Asked Questions
Q: What thickness should a highway noise barrier acrylic panel be?
A: Most motorway and urban road projects use clear acrylic between 15 mm and 25 mm, with 18-20 mm the common middle ground for a balance of acoustic performance and cost.
Q: How does acrylic reduce highway noise if it is transparent?
A:Transparent acrylic reflects and attenuates traffic sound while passing daylight; rated panels are tested to a standard such as EN 1793-2 and come with the documentation.
For a project-specific quotation on transparent acrylic or PC noise barrier panels, email oversales@rpplexiglass.com with your corridor length, panel size and the acoustic standard you must meet.