JavaFX: Animation not moving - animation

Question

I am trying to make an animation in which the car moves from left to right. If it reaches the right end, it starts over again. This type of animation is easy with PathTransition. But I have to change the car speed through the keys UP/DOWN during animation. For some reason I am not able to do that with PathTransition.
So, I am making a simple animation. But the car is not moving in this case. Can someone help me find my mistake:
package exercise_15_29;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.input.KeyCode;
import javafx.scene.input.KeyEvent;
import javafx.scene.layout.Pane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.scene.shape.Line;
import javafx.scene.shape.Polygon;
import javafx.scene.shape.Rectangle;
import javafx.stage.Stage;
import javafx.util.Duration;
import javafx.animation.KeyFrame;
public class Exercise_15_29 extends Application {
static Group car = new Group();
Circle wheel1 = new Circle(15, 95, 5);
Circle wheel2 = new Circle(35, 95, 5);
Polygon body1 = new Polygon();
Rectangle body2 = new Rectangle(0.0, 80.0, 50, 10);
Line path = new Line(0, 90, 500, 90);
int speed = 100;
boolean play = true;
public static void main(String[] args) {
launch(args);
}
public static void moveCar(){
if(car.getLayoutX() == 500)
car.setTranslateX(-500);
else
car.setTranslateX(10);
}
#Override
public void start(Stage primaryStage) {
body1.getPoints().addAll(new Double[]{
10.0, 80.0,
20.0, 70.0,
30.0, 70.0,
40.0, 80.0
});
body1.setFill(Color.BLUE);
body2.setFill(Color.SKYBLUE);
path.setVisible(false);
car.getChildren().addAll(wheel1, wheel2, body1, body2);
Timeline animation = new Timeline(new KeyFrame(Duration.millis(speed),e -> moveCar()));
animation.setCycleCount(Timeline.INDEFINITE);
animation.play();
Pane root = new Pane();
root.getChildren().add(car);
root.getChildren().add(path);
Scene scene = new Scene(root, 500, 100);
scene.addEventFilter(KeyEvent.KEY_PRESSED, e -> {
if (e.getCode() == KeyCode.P) {
if (play)
animation.pause();
else
animation.play();
play = !play;
}
});
primaryStage.setTitle("Hello World!");
primaryStage.setScene(scene);
primaryStage.show();
scene.setOnKeyPressed(e -> {
if (e.getCode() == KeyCode.UP)
animation.setRate(animation.getRate() + 0.1);
else if (e.getCode() == KeyCode.DOWN){
animation.setRate(
animation.getRate() > 0 ? animation.getRate() - 0.1 : 0);
}
});
}
}