Many of Thomas Telford's innovations in highway engineering were way ahead of his time, but are now familiar practice on modern motorways, ranging from using experiments to provide a rational basis for design to constructing massive cuttings, embankments and bridgeworks. The present paper describes the state of Britain's roads in the eighteenth century-when it took 230 h to travel between London and Edinburgh-and then discusses Telford's road-building activities and his novel approach to design. The disagreement with John McAdam is also described, together with an assessment of Telford's contribution to the evolution of modern highway engineering.