Roundabouts reduce casualty crashes by 75% for all vehicles, yet when looking at motorcyclists in particular, they only reduce casualty crashes by 37%. [update note: Scully, J. H., Newstead, S. V., Corben, B. F., & Candappa, N. L. (2009). Effect of past black spot programs on motorcycle safety, Journal of the Australasian College of Road Safety, 20 (4), 23-25.), finding a 77% reduction at new roundabouts in casualty crashes involving motorcyclists, comparable with the result for all road users]

Our research shows that the top 10 road environment factors that influence risk for motorcyclists at roundabouts are:
– geometric design
– number of lanesĀ 
– sight distanceĀ 
– lightingĀ 
– pavement markingsĀ 
– signingĀ 
– landscapingĀ 
– street furnitureĀ 
– speed limitsĀ Ā 
– surface issuesĀ 

Source: Beer K, Aninipoc E, Andrea D, Beer T, Making Roundabouts a Safe System Solution for Motorcyclists, ARSC 2014. Dashcams Australia. Bustle.