Caution!

I do not advise anyone to bicycle through a rotary. Do so at your own risk.

What is a Rotary?

Some states use rotaries, otherwise called traffic circles or roundabouts, where two thoroughfares intersect. They are donut-shaped road configurations with an island usually of grass or other low lying foliage in the middle. In the United States, traffic proceeds counter-clockwise around the circle after entering at multiple locations. Traffic within the rotary has the right of way unless otherwise controlled by a traffic light.

These roadway features are particularly challenging when negotiated by bicycle. I live in Massachusetts where rotaries are inordinately popular and I regularly commute 15 miles or so by bicycle. One of my routes has six - count 'em - SIX rotaries, so I consider myself an authority.

Caution, Again!

First of all, bear in mind that drivers, already annoyed by their commute and in a hurry to get where they are going, are going to be doubly annoyed by the presence of a bicycle in the rotary. They hate the rotary already, and they will hate you as being part of it. So use extreme caution and courtesy, or better yet, plan a route that avoids all rotaries.

Technique

But if you insist on biking through a rotary or you have no choice, here is my technique.

Different conditions dictate different strategies. Following I will describe the conditions of a few of the six rotaries I negotiate on my fastest commuting route and the strategies I use.

Rotary 1: Uphill approach, uphill exit, wide paved shoulder, sparsely traveled suburban thoroughfare. A glance over the left shoulder for traffic entering the rotary from the cross street is sufficient to get me through safely.

Rotary 2: Flat approach, slightly downhill exit, no shoulder, busy intersection. After yielding to any traffic in the rotary, I accelerate into the first opening, matching the speed of the car in front of me. I stay behind that car and watch where they go, staying out of their way, and exit fast.

Rotary 3: Intersection of US1 and West Roxbury Parkway. Downhill approach, uphill exit. I approach at top speed, but am prepared to yield to traffic in the rotary. If possible, I maintain speed through the rotary, merging w/ traffic and exiting fast. If I must yield, I proceed cautiously, staying out of the way of entering / exiting traffic.

Rotary 4: Intersection of East Street and Interstate 95. Slightly uphill approach, heavy traffic including trucks at high speed, glass-and-debris-filled shoulder, uphill exit. I am very circumspect as I enter, navigate, and exit, constantly looking in all directions and adusting speed and trajectory as necessary. Often I get past one exit and stop, waiting for traffic to pass before negotiating the next exit. When I proceed, I accelerate to get past the danger zone as quickly as I can. When exiting, I point at the driver I want to pass in front of as they are entering the rotary and, when I am sure I have their attention, signal my intention. At the same time I remain prepared to stop or take evasive action if my signals are misunderstood.

I hope this either disuades you from attempting rotaries on your bicycle or is helpful to you as you engage in this madness. Personally I like the adrenalin rush, as I'm sure the rabbit does when it dashes across the interstate.