I would say that trunk classification is not the best tag for roads like these despite their widths and traffic volumes, as they are still only local roads. In an urban scenario like this, trunk classification should be applied only to major non-freeway highways that serve as major commuter routes to suburban/exurban communities, or as thruways for non-local traffic—essentially the most important non-freeway highways. Think of the sort of roads you'd use to pass through the city or The Las Vegas Valley doesn't have too many examples of these sort of roads considering how remote and freeway-centric it is, but Route 160 out to Pahrump is a good example of a commuter highway to a major satellite town and Route 146 is a viable alternative route to the freeways for traffic traveling between places like SoCal out to Henderson/Boulder City.

Using another, albeit smaller city which has more trunk routes closer to its urban core, Carson City has a few of prime trunk route examples. US 50 in the west heads out to Sacramento—another relatively close-by metro area, US 395 in the south is more remote but links Carson City to major satellite communities like Minden and Gardnerville and eventually towards SoCal, and US 50 in the east links to Fallon—a relatively significant rural town outside of the immediate metro area. What also makes these highways prime examples of trunk roads are that they don't exclusively serve Carson City and provide thruways for long-distance travel (for example, tourists in Reno can pass through CC via US 395 to Los Angeles, or trucks traveling between Sacramento and Fallon can use US 50 through the city). Las Vegas Boulevard, while a major, high-capacity, and famous road in its own regard, is still effectively only a business route for locals and tourists, rather than being a major inter-regional highway like the previous examples.