There are a few streets here where it is not safe to ride in the street.
4 lanes plus a center turn lane. Two Feet from the curb to the traffic. Posted speed limit is 35 mph, the prevailing traffic is going 40 to 45 mph.
Traffic lights are "timed" so you can go the 6 mile length of the street without hitting a red light. (I swear this city uses the stoplights to bunch traffic together ... 5 to 8 minute green lights. It is really bad at the 5 point intersections if you hit the light there red. Only one direction of traffic gets a green light at a time. I suspect the city "traffic engineer" and/or at least one council member owns a gas station.)
Cyclists are encouraged by law enforcement to ride the sidewalks.
There is also a city ordinance that gets the cyclist a ticket if there is more than six cars backed up behind him/her.
No, it does not matter if the first "driver" behind the cyclist is afraid to pass said cyclist with no less than 40 feet between their vehicle and the cyclist. The cyclist still gets a ticket for blocking/delaying traffic.
In short, if there is a sidewalk/bike path (one in the same in most of this city) on my route, I use it.