Over 1 million.
In 1955 there were more than 3 million cars on the British roads
1
200.0000
Which roads in which country.
15,256 car on the road.
Yes, there are cars (and many other types of vehicles) driving on Irish roads.
Cars were improved tremendously and roads were converted from gravel and dirt to paved roads.
If you are referring to modern British and French roads, the stone-paved roads did not have any advantages over modern roads. Tarmac is a more efficient type of surface. Many of the British and French roads follow the course of the road the Romans had built there.
Because the technology for better roads did not exist, and there was little need for 'good' roads as we know them today. Cars did not exist back then. Dirt tracks were good enough for horse-drawn carts and the like.
Airport
you will never know unless you count every car.