Certain none of the responsible people were interested to take credit for those insignificant bridges. 
The term "mukim" was certain the Malay name for the area smaller than the district level. In Malaysia that term is still in used on the maps. For instance there is a place know as Senai in the State of Johore.On the Map it is listed as Mukim of Senai. The Roman numeric standard was an older form of numbering adopted for used by the the British from the Latin. For instance 
I (one) to X (ten), V (five) and III(three). So when the figure of XVIII is exactly 18 by our new standard. Therefore the name Mukim XVIII of Ang Mo Kio signify the area located on the Map. Presently it not the site of the New Town of Ang Mo Kio but just next along side. It was the housing estate built by the United Overseas Land Limited known as "Faber Gardens". This was the kampong area where our old attap dwelling used to stand at No. 126 A Lorong Kukus. 
In conclusion I suggest that the name of Mukim of Ang Mo kio is far older than the new Town of Ang Mo Kio. It is highly likely than the name was chosen by Town builders following that original name on the Map.