Fixed version is uploaded! It's just a change of like 3 lines, so it might be easier to just manually apply the git diff to your existing project:
diff --git a/SimpleRacingEngine_3D_carmodels.gmx/SimpleRacingEngine_3D_carmodels.project.gmx b/SimpleRacingEngine_3D_carmodels.gmx/SimpleRacingEngine_3D_carmodels.project.gmx
index 622e83f..59e20a7 100644
--- a/SimpleRacingEngine_3D_carmodels.gmx/SimpleRacingEngine_3D_carmodels.project.gmx
+++ b/SimpleRacingEngine_3D_carmodels.gmx/SimpleRacingEngine_3D_carmodels.project.gmx
@@ -105 +105 @@
- <constants number="8">
+ <constants number="9">
@@ -108,0 +109 @@
+ <constant name="TRACK_U_PRECISION">10000</constant>
diff --git a/SimpleRacingEngine_3D_carmodels.gmx/objects/obj_car.object.gmx b/SimpleRacingEngine_3D_carmodels.gmx/objects/obj_car.object.gmx
index 3073c84..0d4bd06 100644
--- a/SimpleRacingEngine_3D_carmodels.gmx/objects/obj_car.object.gmx
+++ b/SimpleRacingEngine_3D_carmodels.gmx/objects/obj_car.object.gmx
@@ -36,0 +37 @@ u = 1.00//Forward coordinate
+uu = TRACK_U_PRECISION
diff --git a/SimpleRacingEngine_3D_carmodels.gmx/objects/obj_trackcontrol.object.gmx b/SimpleRacingEngine_3D_carmodels.gmx/objects/obj_trackcontrol.object.gmx
index c55c5c8..c8882e3 100644
--- a/SimpleRacingEngine_3D_carmodels.gmx/objects/obj_trackcontrol.object.gmx
+++ b/SimpleRacingEngine_3D_carmodels.gmx/objects/obj_trackcontrol.object.gmx
@@ -73 +73,2 @@ global.ufactor = 1/global.tracklength
+global.uufactor = TRACK_U_PRECISION/global.tracklength
@@ -105,0 +107 @@ for(car = 0; car < global.cars_total; car++){
+ n.uu= n.u*TRACK_U_PRECISION
diff --git a/SimpleRacingEngine_3D_carmodels.gmx/scripts/player_apply_movement.gml b/SimpleRacingEngine_3D_carmodels.gmx/scripts/player_apply_movement.gml
index 3e6cf06..3f204c1 100644
--- a/SimpleRacingEngine_3D_carmodels.gmx/scripts/player_apply_movement.gml
+++ b/SimpleRacingEngine_3D_carmodels.gmx/scripts/player_apply_movement.gml
@@ -16 +16,2 @@ alpha = angle_difference(trackdir,argument0)
-u += lengthdir_x(argument1*global.ufactor,alpha)
+uu += lengthdir_x(argument1*global.uufactor,alpha)
+u = uu/TRACK_U_PRECISION