20-Year Prospect
Unfortunately, this job has a growth rate lower than the national average, so that's a bit of a bummer (source). It's projected that between 2012 and 2022, there will be only about 30,000 new job openings, making highway maintenance a rather competitive field (source). Therefore, you might have to fight your way into securing a position, or maybe even move somewhere else.
If you live somewhere where people are heavily dependent on highways, then you might have a better shot at a gig. Yeah, it's hard to get in, but we've got you covered―certain states have a bigger employment rate for highway maintenance workers (source).
The good news is that this country's highway systems are starting to age (not so gracefully, we might add) and will need a lot of upkeep. If you manage to secure a position in the field, you and your coworkers probably won't want for work anytime soon.
Not till we have hovercars at least.