What about water filled plastic barriers? http://www.made-in-china.com/showroom/resourcesint/product-detailzqMJlfFDaQGv/China-Water-Filled-Plastic-Barrier.html
They may not be permanent, but some stay in place for long periods of time. _______________________________________________ Tagging mailing list [email protected] http://lists.openstreetmap.org/listinfo/tagging
