Roundabouts are a relatively new type of intersection control in Canada, and as such
there is growing interest in how they compare relative to established types of control
using stop signs and traffic signals. Roundabouts have a clear set of advantages and
disadvantages compared to these traditional intersections, which are set out in Section 2
of this paper.
Intersections play an critical role in the operation of a road network. Therefore it is
important to make sound defensible decisions about type of intersection control, both
when implementing a new intersection and when modifying an existing intersection (or
road section) due to motor vehicle capacity or user safety issues. When stop and traffic
signal control were the only alternatives this process was straightforward and
accomplished using traffic signal warrants based on side street delay and historic safety
performance. Now that roundabouts are a possible alternative the process is potentially
much more complicated. A number of road agencies in Canada and the United States
have developed practices to aid in making a decision about type of control. A selected
range of these practices is described in Section 3 of this paper as well as practices in
Australia, which is a country with similar density and road network characteristics as
Canada and the US but a much longer history of roundabout implementation.
Section 4 of this paper synthesizes the various roundabout implementation practices
descried in Section 3 as being either basic intersection-level, “enhanced” intersectionlevel,
or network-level.
