Well, the truck was definitely real, not an artists concept sketch. An image gallery at the Nevada Department of Transportation website shows the following picture:
The caption simply labels it as an 'Early Department of Highways truck."
Many other interesting images in this gallery, Historical Image Gallery 1917-1939, which gives us a date range, but no other information.
Since the question has been edited to focus on the time, we can narrow this down. The book lists vehicles from 1897 to 1927, but the gallery from NDOT is from 1917 to 1939, so using these two date ranges we can conclude this truck ran sometime in the ten year span between 1917 to 1927.
Looks like we might be able to tighten that a little bit more. The truck this device is built on appears to be a WW1 era US Army vehicle known as the Standard B "Liberty" truck
Since the wiki article states these trucks were prototyped in 1917, with first
official production of the First-type truck began in January 1918
We can assume this truck didn't reach civilian hands until some time after the armistice in November 1918.
Following the war, many Class-B Liberty trucks were sold-off surplus
to the civilian market and other militaries.
so 1919 or 1920 is a more likely earliest possible date.