Road numbers' colors/shapes in Google Maps

Question

I have noticed that road numbers in Google Maps have different colors and shapes from one country to another, here are some examples:

Does it mean anything? or is it just to match the country's symbols? I could not find a legend to explain this in Google Maps.

Answer 1

It's just to match the normative symbols to some degree that are usually used for each of the various types of roads in each country.

You can fairly easily check this by comparing any maps or roadsigns in the country you're from, the country you're in, or international road atlases, which also try to match the normative symbols.

By "types" or "grades" of road, that means different symbols are used for things such as "expressways", "freeways", "highways", "interstates", etc.

The exact terms and definitions vary from country to country and language to language, but they cover such things as what the maximum speed is, how many lanes there are, whether there will be intersections or traffic lights, whether they cross boundaries between countries, states, provinces, prefectures, etc, whether they are paved or unpaved, whether they are residential, etc.

For those adamant for references for common knowledge and easily checked observations, there is a Wikipedia article, currently under the title "Highway shield". It has lots of reproductions of the symbols/logos/shields for various grades of road used in various countries.

• The N40 is a National Highway of Pakistan:
  

• The A1 is a Highway in Nigeria.

• The one that jumps out as the most obvious is the one in your top-right map. It's obviously an Interstate in USA to anyone from the US, who's visited the US, or who's seen enough US movies and TV:
  

• The N20 and N330 are National Routes (Route nationale) of France:
  ,
  ^{(By ZeroFour (Own work), via Wikimedia Commons)}

• The "30" is a highway in Saudi Arabia, but doesn't seem to have a Wikipedia article in either English or Arabic. Nor does there seem to be an article in either Wikipedia about the country's highway system in general.

• The one in the bottom right is also from the US, but is not an interstate, it's a U.S. Highway:
  

Answer 2

I would like to expand on hippie's excellent answer with respect to Saudi Arabia. The highways symbols with the country map outline are national highways, which is a recent development as Saudi Arabia continues to build out its road infrastructure.

In Saudi, the older signs simply had the name of the major destination, and the road was named for the major cities along its route. This is a sign on the Dhahran-Khobar highway:

Later on, the cross-country roads were numbered in a state highway system; these signs now have the road number and if it has the Saudi country outline, its a national highway. In this image, you see Makkah (40 West), Qassim (65 N) and Kharj (65 S).

Saudi state highway 40 runs from Makkah (on the west coast) to Dammam (on the east coast); it is one of the most used national highways in Saudi Arabia, as it passes through Riyadh (the capital).

As you can see, the signs are in English and Arabic, but the road symbols are in Arabic numerals with the direction in English and Arabic.

In addition to the above, there are other road symbols as well. For example, this sign displays a couple of them:

From the top left, there is:

1. 40 W (main highway leading to Makkah)
2. The road symbol for the Holy Mosque (this is shown when roads lead to Makkah and within Makkah to the Holy Mosque). These were added as a universal pictogram (similar to the airplane outline that identifies an airport).
3. The white sign with 80 M is the local motorway designation.
4. The symbol after it 267 is the regional road marker (a local road that is off the main highway). In this case, it leads to the mountain city of Taif).