The statement 'By 1910, the motor car was plainly conquering the highway' means that
By 1910, the motor car was plainly conquering the highway. The private car was now part of every rich man’s establishment, although its price made it as yet an impossible luxury for most of the middle class. But for the adventuresome youth, there was the motorcycle, a fearsome invention producing accidents and ear-splitting noises. Already the dignified carriages and smart pony-traps were beginning to disappear from the roads and coachmen and grooms unless mechanically minded, were finding it more difficult to make a living.
The roads which had gone to sleep since the coming of the railway now awoke to feverish activity. Cars and motorcycles dashed along them at speeds which rivalled those of the express trains and the lorry began to appear. Therefore, the road system was compelled to adapt itself to the volume and speed of traffic for which it had never intended. Its complete adaptation was impossible, but the road surface was easily transformed and during the early years of the century, the dustiness and greasiness of the highways were lessened by tar-spraying. To widen and straighten the roads and get rid of blind corners and every steep gradient were tasks which had scarcely been tackled before 1914. The situation was worst of all in towns where not only was any large scheme of road widening usually out of the question but also where crowding and danger were all too frequently increased by the short-sighted eagerness of town authorities in laying down tramlines.
Yet, it was not only the road system that was in need of readjustment; the nervous system of those who used and dwelt by the road suffered. The noises caused by the conversion of the roads into speedways called for a corresponding tightening up of the nerves and especially in the towns, the pedestrian who wished to preserve life and limb was compelled to keep his attention continually on the stretch; to practise himself in estimates of the speed of approaching vehicles and to run or jump for his life if he ventured off the pavement.