Any infinite length that it needs to be in order to get from one place to another.
By which you mean the length of a road? Sure, why not?
20km
To measure the stem length on a road bike, use a measuring tape to determine the distance from the center of the handlebar to the center of the fork steerer tube. This measurement will give you the stem length of your road bike.
5,00000000000cm or 692mm
The recommended valve stem length for a road bike is typically 42mm to 60mm, depending on the depth of the rim.
Kilometers
You can measure distance or length in kilometers, such as the distance between two points, the length of a road, or the size of a country.
The recommended spindle length for a road bike with a compact frame design is typically around 103-107mm.
In Malaysia, it cost RM20-30K to build a road of 100m in length.
"Long" and "length" are related but not the same. "Long" is an adjective describing the extent of something from one end to another, while "length" is a noun that refers to the measurement of that extent. For example, you might say a road is "long," but the "length" of the road can be measured in miles or kilometers.
2,500 km
6900.40589828 km