I know the question might seem stupid, but can you move? Relocate to a better town?
I love my job, been at the same big, urban high school for 26 years 
I live right in the neighborhood, the ten mile loop going and coming is just a self-imposed thing.
When people ask is it safe I reply......
"Yes.... most of the time" 
A complex issue.... at home on my street there are a number of drug dealers and the house next door got shot up a couple of years back, yet being an accepted part of the neighborhood we can and do leave our car doors unlocked, and you could lean on our front door and get in. No problems yet.
MOST people, even in "bad" areas, are decent, its just the criminal minority you need to mind, most often after dark.
I ride in a single layer of loose nylon; oversized shirt and pants tucked into socks. This photo was taken when I rode to New York State in 2014, pretty much I look like that except no straw hat or reflective vest while commuting. I usually wear a bandanna on my head.
Seen at the last minute at night, in car headlights or pedestrians, people who don't know me generally assume I am a homeless guy. Likewise my bicycles, tho' quietly tricked out with good-quality components, do not look flashy.
I realize my situation is unique and that my solutions wouldn't work for everyone.
The one scary situation in the three years I have been doing this regularly was on a quarter-mile stretch of dark access road running alongside a busy urban loop highway. I was riding against traffic as I must do on that stretch, no lights (I just bale off of the roadway when cars are approaching). I saw the guy some distance ahead going the same way as me, silhouetted by the lights at the next intersection. Shaved head as is common among gang members here, strongly built as ex-cons generally are, walking fast, obviously in a hurry to get somewhere.
I sped up and gave him a wide berth on the roadway, he didn't see me until I passed him. He didn't say anything, just ran after me after I passed, prob'ly wanting the bike to get to where he was going.
I'm just happy he weren't walking in the OTHER direction.....
Mike