Merthyr Tydfil is a Welsh Unitary Authority. It was created in June 2009.
| Year | All Motor Vehicles | Cars and Taxis | Road Network Total Length |
|---|---|---|---|
| 2000 | 208,700,000 | 172,200,000 | 208.4 miles (335.3 km) |
| 2001 | 206,400,000 | 170,000,000 | 208.8 miles (336.0 km) |
| 2002 | 216,700,000 | 179,300,000 | 209.3 miles (336.8 km) |
| 2003 | 215,200,000 | 177,600,000 | 209.6 miles (337.4 km) |
| 2004 | 222,300,000 | 181,600,000 | 210.0 miles (338.0 km) |
| 2005 | 229,100,000 | 187,000,000 | 210.5 miles (338.8 km) |
| 2006 | 235,000,000 | 192,200,000 | 215.3 miles (346.5 km) |
| 2007 | 241,900,000 | 195,800,000 | 215.1 miles (346.2 km) |
| 2008 | 240,000,000 | 194,300,000 | 215.3 miles (346.5 km) |
| 2009 | 241,100,000 | 195,900,000 | 215.1 miles (346.2 km) |
| 2010 | 241,800,000 | 195,700,000 | 215.6 miles (346.9 km) |
| 2011 | 243,500,000 | 198,000,000 | 214.6 miles (345.4 km) |
| 2012 | 245,100,000 | 198,000,000 | 216.2 miles (347.9 km) |
| 2013 | 246,900,000 | 199,000,000 | 216.4 miles (348.2 km) |
| 2014 | 248,200,000 | 199,400,000 | 216.7 miles (348.8 km) |
| 2015 | 257,900,000 | 205,700,000 | 216.7 miles (348.8 km) |
| 2016 | 265,900,000 | 211,800,000 | 218.7 miles (351.9 km) |
| 2017 | 255,100,000 | 205,500,000 | 216.6 miles (348.6 km) |
| 2018 | 261,200,000 | 209,800,000 | 216.4 miles (348.3 km) |
| 2019 | 262,900,000 | 212,400,000 | 216.5 miles (348.4 km) |
| 2020 | 196,800,000 | 154,400,000 | 216.2 miles (348.0 km) |
| 2021 | 242,300,000 | 188,700,000 | 216.1 miles (347.8 km) |
| 2022 | 269,300,000 | 211,700,000 | 216.2 miles (348.0 km) |
| 2023 | 277,400,000 | 221,900,000 | 215.7 miles (347.2 km) |