Abstract
The effects of small roundabouts on emissions and fuel consumption were evaluated using the "car-following" method in a before/after study. The results showed that at a roundabout replacing a signalised junction, CO emissions decreased by 29%, NOx emissions by 21% and fuel consumption by 28%. At roundabouts, replacing yield regulated junctions, CO emissions increased on average by 4%, NOx emissions by 6% and fuel consumption by 3%. The results indicate that the large reductions in emissions and fuel consumption at one rebuilt signalised junction can "compensate for" the increase produced by several yield-regulated junctions rebuilt as roundabouts. (Author/publisher).