Furlong in the Hoddle Grid of Melbourne are also one furlong in length. Much of Ontario, Canada, was originally surveyed on a ten-furlong grid, with major roads being laid out along the grid lines. Now that distances are shown on road signs in kilometres, these major roads are almost exactly two kilometres apart. The exits on highways running through Toronto, for example, are generally at intervals of two kilometres. The furlong is also a base unit of the humorous FFF system of units. The exact conversion of the furlong to SI units varies slightly among English-speaking countries. In Canada and the
Furlong United Kingdom, which define the furlong in terms of the international yard of exactly 0.9144 metres, a furlong is 201.168 m. Australia does not formally define the furlong, but it does define the chain and link in terms of the international yard. In the United States, which defines the furlong, chain, rod, and link in terms of the U.S. survey foot of exactly metre, a furlong is approximately 201.1684 m long. The United States does not formally define a "survey yard". The difference of approximately two parts per million between the U.S. value and the "international" value is insignificant for