Tarmac is actually tarmacadam which is tar + macadam, which is a kind of road only without the tar part of the tarmac. This is how they used to insure the quality of macadam:Size of stones was central to McAdam's road building theory. The lower 8 in (20 cm) road thickness was restricted to stones no larger than 3 inches (7.5 cm). The upper 2-inch-thick (5 cm) layer of stones was limited to stones 2 centimetres (3⁄4 in) in diameter; these were checked by supervisors who carried scales. A workman could check the stone size himself by seeing if the stone would fit into his mouth.Also macam roads are named like that because McAdam invented them.
xX_sp00ks_Xx, Today at 09:05:49 am
The naming of Macadamia nuts have nothing to do with this, but were named after John Macadam, an Australian chemist.