add downshift only for gears above 1

VectoCore/VectoCore/Models/Declaration/DeclarationData.cs

@@ -265,7 +265,10 @@ namespace TUGraz.VectoCore.Models.Declaration
 
 				var fldMargin = ShiftPolygonFldMargin(fullLoadCurve.FullLoadEntries, engineSpeed85kmhLastGear * 0.9);
 				var downshiftCorr = MoveDownshiftBelowFld(Edge.Create(p6, p3), fldMargin, 1.1 * fullLoadCurve.MaxTorque);
-				var downShift =
+
+				var downShift = new List<ShiftPolygon.ShiftPolygonEntry>();
+				if (gear > 0) {
+					downShift =
 						new[] { p2, downshiftCorr.P1, downshiftCorr.P2 }.Select(
 							point => new ShiftPolygon.ShiftPolygonEntry() {
 								AngularSpeed = point.X.SI<PerSecond>(),
@@ -273,7 +276,7 @@ namespace TUGraz.VectoCore.Models.Declaration
 							}).ToList();
 
 					downShift[0].Torque = maxDragTorque;
-
+				}
 				var upShift = new List<ShiftPolygon.ShiftPolygonEntry>();
 				if (gear >= gears.Count - 1) {
 					return new ShiftPolygon(downShift, upShift);