 Later on, they did not hold up to higher-speed motor vehicle use.Methods to stabilise macadam roads with tar date back to at least 1834 when John Henry Cassell, operating from "Cassell's Patent Lava Stone Works" in Millwall, patented "Pitch Macadam".This method involved spreading tar on the subgrade, placing a typical macadam layer, and finally sealing the macadam with a mixture of tar and sand.