I happen to be a traffic engineer who operates signals in the USA. We may not have the most advanced technology but I can assure that we don't not write code to operate our signals. We do enter different parameters that govern the amount of time that you have to wait.
In most situations it comes down to if you want to favor vehicles or if you want to favor pedestrians. As everyone has mentioned it is difficult to accommodate both as they would like.
Also as government worker I can assure we are not highly paid. We make a decent living but there is actually a shortage of people right now that want to do the work.
I trust my sources (mainly, a city planner that's been working here for 30 years). Certain engineering specialists out here sometimes make absolutely absurd amounts of money because they work on contracts with such limited scope, the equivalent of 600k or more a year.
Also, I think the notion of having to balance pedestrians' interests with drivers' is a cultural thing that filters down from the MUTCD and into traffic engineering. Drivers create almost all the risk associated with our road system yet their interests are prioritized highly. Traffic engineers are bound to this deadly model that prioritizes drivers, because road construction projects are not given government funds (which they often completely rely on) unless they conform to MUTCD.
In most situations it comes down to if you want to favor vehicles or if you want to favor pedestrians. As everyone has mentioned it is difficult to accommodate both as they would like.
Also as government worker I can assure we are not highly paid. We make a decent living but there is actually a shortage of people right now that want to do the work.