For reasons outside the scope of this post, I park my car in a lot near Amnesia (9th and Revolucion) and walk back and forth on Revolucion from the parking lot to the Zona Norte.  I've been doing this for years and the biggest problem I've had are the "barkers" trying to get me to visit places and buy stuff.

Revolucion is well lighted.  There are lot of clubs open at nigh and, day and night, there's lots of "movement."  It's safe.  (You're in a lot more danger of tripping and falling--especially if you've been drinking--than you are of being mugged.)

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Tijuana today is like Chicago was during Al Capone's era, except it's drug dealers instead of rum runners battling it out with the cops (and each other).  The violence is among cartel members and between cartel members and the cops.  

TJ violence occurs in the poor outlying areas of Tijuana, like La Florida and Matamoros. It doesn't occur where tourists visit, including (but not limited to) Avenida Revolucion and the Zona Norte.