At what point does a road become too busy/fast to ride on safely? Upfront, I'm willing to admit that I have some nervousness when it comes to commuting by bike that I need to get over. However, I want to know if all of that nervousness is unfounded, or if some of it is valid.

I live in the Southeastern U.S., where bikes aren't really regarded as things that belong on the road at all. This is a map from this article published on Wired in 2015:



As you can see, the Southeast doesn't fare too well. My specific question, though, is about roads like these (image credit: Google Maps):

I've ridden on 4+ lane roads before, but never with a speed limit higher than 35 MPH (~55 KPH), and often with a bike lane. The speed limit on this road is 55 MPH (~90 KPH), and this road and others like it (with no bike lanes) would be unavoidable on my commute. Are roads like these safe to ride on or is the speed of traffic too fast?



Edit: Sidewalk Clarification

Since a lot of people have mentioned sidewalks as a potential option, I figure it's worthwhile to add some details. First, the sidewalk on this road is not consistent. There are multiple spots where it just stops and then resumes 30 or 40 feet later. In other places, it stops and resumes on the other side of the road... but without a crosswalk to get there. Secondly, I checked our state laws, and riding a bike on a sidewalk is illegal. 

As an aside, like many U.S. states, we also have an FTR (Far-To-the-Right) law, meaning riders can't take the lane (except for in a few circumstances). The state really isn't bicycle friendly.
Determining an acceptable risk level is really a subjective personal assessment, no one can tell you whether or not something is of an acceptable level of risk.  As such I will give you my judgement criteria for riding on roads shared with automobiles.


I avoid roads without a large shoulder or bike lane.  While many still advocate for taking a lane, the failure mode (e.g., a rear collision) presents too much of a risk in my opinion.
I avoid large speed differentials, I would qualify vehicles traveling over 50 kph as having a large speed differential.  This reduces reaction times as the closing velocity is quite high, which can lead to accidents.  I don't trust that most drivers are doing an effective job of scanning the road ahead of them.
I also try to avoid roads with much traffic, either by riding in off-times (e.g., 5 am) or sticking to largely unused roads. This further reduces the risk.
Finally, roads with good sight lines and acceptable closing speeds are preferred over roads with bad sight lines and higher closing speeds. (Thank you to @gerrit for the suggestion.)


I also ride away from traffic whenever I can so I tend to mix in a lot of dirt and asphalt.  For very quiet rural roads with low speed limits I am happy to forgo criteria (1) because there are fewer interactions with vehicles and you tend to stick out like a sore thumb in that scenario. But I also mitigate this further by only using these roads in good weather conditions (e.g., not at night in the rain).

In terms of line of clear sight I feel this only provides some safety as it still requires drivers to scan ahead and recognize objects.  Many do a poor job of this, or the search images they are looking for do not include cyclists so they can miss an utterly obvious rider at the side of the road.  This is why I put line of sight last.

From my criteria I don't think you need a critical assessment of your photo.  I would suggest looking at alternate routes (perhaps ones that are less direct) or look on sources such as Open Street Maps, as they have a good cycling path maps including off-road/dirt paths  that can be used to tie together routes so that busy and dangerous roads can be circumvented. 

At least where I live, this has been a good strategy.