RT Journal Article T1 Numerical Computation of Egg and Double-Egg Curves with Clothoids A1 Vázquez Méndez, Miguel Ernesto A1 Casal Urcera, Gerardo A1 Ferreiro Darriba, Juan Bosco K1 Clothoid K1 Cornu spiral K1 Euler spiral K1 Highway connections and interchanges K1 Egg and double-egg curves AB The clothoid, also known as Cornu spiral or Euler spiral, is a curve widely used as a transition curve when designing the layout of railway tracks and roads because of a key feature: its curvature is proportional to its length. The classical method to compute a clothoid is based on the use of Taylor expansions of sine and cosine functions, usually starting with zero curvature at the initial point. In this paper the clothoid is presented as the only curve with a constant rate of change of curvature, which parametrization can be obtained by solving an initial value problem. In this initial value problem the curvature at the starting point can be chosen, being able to develop simple, efficient, and accurate algorithms to connect two oriented circumferences by means of clothoids. These algorithms are presented as a useful tool for designing egg and double-egg curves in highway connections and interchanges PB American Society of Civil Engineers SN 0733-9453 YR 2020 FD 2020 LK http://hdl.handle.net/10347/32521 UL http://hdl.handle.net/10347/32521 LA eng NO Vázquez-Méndez, M. E., Casal, G., & Ferreiro, J. B. (2020). Numerical computation of egg and double-egg curves with clothoids. Journal of Surveying Engineering, 146(1), 04019021 NO Revised version (June, 2021) of the preprint corresponding to the paperpublished in Journal of Surveying Engineering. NO The authors would like to thank Loris Lori from Terni, Italy (Centro SviluppoMateriali and ThyssenKrupp Acciai Speciali Terni), for replicating all examples andpointing out the misprints corrected in red in this revised version. M.E. VázquezMéndez thanks the funding support from project MTM2015-65570-P of Ministerio deEconomía y Competitividad (Spain)/FEDER. DS Minerva RD 28 abr 2026