Depends on many factors, including how much you value human life. Quoting from <a href="http:&#x2F;&#x2F;onlinepubs.trb.org&#x2F;onlinepubs&#x2F;nchrp&#x2F;nchrp_rpt_672.pdf" rel="nofollow">http:&#x2F;&#x2F;onlinepubs.trb.org&#x2F;onlinepubs&#x2F;nchrp&#x2F;nchrp_rpt_672.pdf</a> :<p>&gt; The initial design and construction cost of a roundabout can vary significantly depending on the roundabout size, right-of-way impacts, illumination requirements, and other design or aesthetic features that may be desired. A new single-lane roundabout intersection in an unbuilt environment can have construction costs comparable to a traffic signal. However, as the size of the roundabout increases, particularly in a fully built-out commercial or residential area, the cost of roundabout construction can be higher than that of a traffic signal, depending on the footprint of the roundabout relative to that needed for the signal. However, the ongoing operations and maintenance cost of a roundabout can be less than that for a signal, with the possible exception of increased illumination needs for a roundabout. Although the initial construction cost may be more, a roundabout can have less operating and maintenance costs than a traffic signal, and the service life of a roundabout is significantly longer, approximately 25 years, compared with 10 years for a typical signal (2). Roundabouts also provide substantial cost savings to society due to the reduction in crashes, particularly fatal and injury crashes, over their service life.<p>It also depends on how much you value people&#x27;s time waiting for a light to change, as described in the parent scenario.