NEW FORM OF ROAD RAILWAY TRANSITION CURVE

Road and railway transition curves have again become the subject of im portant scientific research and serious traffic engineering analyses b ecause of high driving speeds and demands for automatic drive (i.e., c ar pilots). This article shows, in an original way, how to define or r econstruct the track of a vehicle when passing the elements of a conti nuous curve (straight lines, circles) so the track (curve) suits all r equirements to which transition curves must be adapted. The praxis whe reby a known mathematical curve (e.g., a cubic parabola, lemniscate, o r chlotoid) was assumed as a transition curve and its suitability was analyzed has been passed over. On the basis of assumed kinematics mode ls of the motion of a vehicle along joint alignment elements with a ch anging radius of curvature, the writers have analyzed different transi tion curves resulting in safe, comfortable, and economic driving. The curve resulting from a parabolic velocity chart of front wheel rotatio n during such movement which found the most suitable has been named PO LUSA; a geometrical analysis of POLUSA has been performed and a manual for practical use completed.