This　paper　presents　a　reliability-based　method　for　the　design　of　intersection　sight　distance　(ISD)　at　traffic　roundabouts　using　the　linear　and　nonlinear　deceleration　profiles　of　the　entry　vehicles.　The　reliability　method　is　based　on　the　first-order　second　moment　method　which　is　simple　and　relatively　accurate　compared　with　advanced　methods.　The　nonlinear　deceleration　profile　includes　a　shape　parameter　that　produces　the　linear　profile　as　a　special　case.　Deterministic　and　reliability-based　formulas　for　the　required　ISD　for　an　approaching　vehicle　are　developed　for　the　entry　vehicle　on　the　left　and　the　vehicle　on　the　circulating　roadway.　Then,　the　design　values　of　the　ISD　legs,　applicable　to　any　type　of　roundabout,　are　presented　for　different　probabilities　of　non-compliance　(Pnc)　and　different　coefficients　of　variations.　For　the　special　case　of　single-lane　symmetrical　roundabouts,　which　have　a　well-defined　geometry,　the　lateral　clearance　needs　are　established.　The　sensitivity　analysis　shows　that　ISD　is　very　sensitive　to　both　the　mean　and　variance　of　the　critical　headway.　The　results　show　that　the　deterministic　method　results　in　ISD　values　that　correspond　to　a　very　small　Pnc,　indicating　that　the　method　is　very　conservative.　The　proposed　method,　which　provides　flexibility　in　selecting　ISD　for　any　given　Pnc,　should　be　of　interest　to　highway　designers　and　practitioners　to　promote　roundabout　safety.　©　2020　by　the　authors.