The biggest problem is usually avenues (four lane roads, two in each direction) with high speed traffic. Around here that means lots of people turning left and

The biggest problem is usually avenues (four lane roads, two in each direction) with high speed traffic. Around here that means lots of people turning left and right and cars average about 40mph, many do 60mph. Unprotected bike lanes on these roads exist but over the past decade I've personally watched two people die on bikes from right turns and heard of dozens of collisions.