I am trying to create a delay before the cars come back to their initial y position after they avoid the truck in this animation. Currently, I have the timer in the avoidance () method but it doesn't seem to work no matter where I put it. Also, my blue car behaves differently to the collision than the green one and I see now logical reason for this?

/* collision detection and avoidance mechanism*/


// Declare the object variables for this program

Vehicle myVehicle1;      
Vehicle myVehicle2;     
Truck bigRedFireTruck;      
Timer timer;     


void setup() {     
  size(400, 200);      

  myVehicle1 = new Vehicle(color(0, 255, 0), 0, 100, 20, 10, 2);      
  myVehicle2 = new Vehicle(color(0, 0, 255), 0, 10, 20, 10, 1);     
  bigRedFireTruck=new Truck (color (255, 0, 0), width, height/2, 30, 14, 8, 1.5, 4);     

  timer = new Timer(200);    
  timer.startTimer();      
}      

void draw() {      
  background(225);      

  myVehicle1.drive();      
  if (myVehicle1.collDetect(bigRedFireTruck)) {      
    print("collision");
    myVehicle1.avoidance(bigRedFireTruck);      
  }
  myVehicle1.display();     

  myVehicle2.drive();     
  if (myVehicle2.collDetect(bigRedFireTruck)) {      
    print("collision");
    myVehicle2.avoidance(bigRedFireTruck);    
  }
  myVehicle2.display();      
  bigRedFireTruck.drive();     
  bigRedFireTruck.display();      
}      


// code for the superclass called Vehicle

class Vehicle {    


    // all of the fields for the class called Vehicle: declare the properties for the class called Vehicle

    color c;     
  float xpos;     
  float ypos;     
  float vwidth;     
  float vheight;      
  float xspeed;      
  float yspeed;      
  float ydirection;      
  float yReturn;      


  // constructor for the class called Vehicle

  Vehicle(color tempC, float tempXpos, float tempYpos, float tempvwidth, float tempvheight, float tempXspeed) {       // CFSR: create the constructor of the Vehicle class and declare its temporary variables

    c = tempC;     
    xpos = tempXpos;     
    ypos = tempYpos;      
    vwidth=tempvwidth;      
    vheight=tempvheight;     
    xspeed = tempXspeed;     
     yspeed=0.0;      
    yReturn=tempYpos;   
    ydirection=1;      
  }    



  // methods for the class called Vehicle

  void drive() {     
    xpos = xpos + xspeed;     
    if (xpos > width) {     
      xpos = 0;     
    }      
   yspeed= 0.0;
    ypos = yReturn;
    ydirection=1;     
    ypos = ypos+yspeed*ydirection;  
    if (ypos <0-vheight) {
    }
  }   


  void display() {     
    stroke(1);      
    fill(c);     
    rectMode(CENTER);      
    rect(xpos, ypos, vwidth, vheight);     
  }      


  // collision detection method for the vehicle class: function that returns true or false based on whether the bigredtruck collides with another vehicle

  boolean collDetect(Truck vcollision) {
    if (xpos-vwidth/2<=(vcollision.xpos+vcollision.truckTotalWidth) && xpos+vwidth/2 >= vcollision.xpos && ypos-vheight/2<=(vcollision.ypos+vcollision.vheight/2) && ypos+vheight/2 >= (vcollision.ypos-vcollision.vheight/2))
    {
      return true;
    }
    else {
      return false;
    }
  }       // end of the collision detection method for the vehicle class


  // avoidance mechanism method for the vehicle class

  void avoidance(Truck tavoidance) {
    if (timer.endTimer()) {
      ypos = yReturn;
      timer.startTimer();
    }

    if (ypos-tavoidance.ypos>0) {
      ydirection=ydirection*1;
    }
    else {
      ydirection=ydirection*-1;
    }
    yspeed=20;
    ypos = ypos+yspeed*ydirection;
  }       // end the avoidance mechanism function
}       // end the block for the class called Vehicle


class Truck extends Vehicle {      

    // declare all of the properties for the subclass called Truck that are not properties of the superclass Vehicle

    int strokeWeightTruck;       // declare the variable that will be used to set a strokeweight for the objects of the truck class different than the strokeweight of the vehicle class
  float truckCabinWidth;       // declare the variable that will be used to determine the width of the cabin part of the truck

  float spaceBtwCabinVan;       // declare the variable that will be used to determine the space between the cabin and the van parts of the truck
  float truckTotalWidth;       // declare the variable that will be used to determine the total width of the cabin
  float truckCabinHeight;       // declare the variable that will be used to determine the height of the cabin part of the truck
  float truckVanXCenter;       // declare the variable that will be used to determine the middle of the van part of the truck to draw its rectangle in rect(CENTER) mode;
  float angle;       // declare the variable that will control the position of the sin wave for the truck object(s) to move
  float truckMiddleYPos;       // declare the variable that will determine the Y position from which the sin motion occurs when the truck object(s) will move
  float truckYRangeOfMotion;       // declare the variable that will determine the radius of the sin motion when the truck object(s) will move
  float speedOfSinWaveMovement;       // declare the variable that will impart a change in the angle that controls the sin wave for the truck object(s) to move


  Truck (color tempC, float tempXpos, float tempYpos, float tempvwidth, float tempvheight, float tempTruckCabinWidth, float tempXspeed, int tempstrokeWeightTruck) {       // create the constructor of the Truck class and declare its temporary variables
    super (tempC, tempXpos, tempYpos, tempvwidth, tempvheight, tempXspeed);    

    // initialize the parameters for the constructor of the subclass called Truck

    strokeWeightTruck=tempstrokeWeightTruck;     
    truckCabinWidth=tempTruckCabinWidth;     

    // initialize the local variables for the display of the subclass called Truck

    truckCabinHeight=tempvheight;      
    spaceBtwCabinVan=truckCabinWidth;      
    truckTotalWidth=truckCabinWidth+spaceBtwCabinVan+vwidth;      
    truckVanXCenter=truckCabinWidth+spaceBtwCabinVan+vwidth/2;      

    // initialize the local variables for the movement (driving) of the subclass called Truck

    angle=0.0;      
    truckMiddleYPos=height/3;     
    truckYRangeOfMotion=height/3;    
    speedOfSinWaveMovement=0.04;      
  }      


  void drive() {    
    xpos = xpos - xspeed;      
    if (xpos < -vwidth) {     
      xpos = width;     
       }     
    ypos=truckMiddleYPos+sin(angle)*truckYRangeOfMotion;      
    angle+=speedOfSinWaveMovement;      
  }    


  void display () {      
    strokeWeight(strokeWeightTruck);    
    fill (c);    
    rectMode(CENTER);      
    rect (xpos+truckVanXCenter, ypos, vwidth, vheight);      
    rect (xpos+truckCabinWidth/2, ypos, truckCabinWidth, truckCabinHeight);       
    line (xpos+truckCabinWidth, ypos, xpos+(truckCabinWidth+spaceBtwCabinVan), ypos);      
    strokeWeight(1);   
  }      
}      


// code for the class called Timer

class Timer {     

      int resetTime;     
  int delayAvoidance;      


    Timer(int tempdelayAvoidance) {      
    delayAvoidance = tempdelayAvoidance;     
  }     


    // method to start the timer for the delay

  void startTimer() {      
    resetTime=millis();      
  }     
 

  // method to determine whether the delay has passed

  boolean endTimer () {        
    int passedTime=millis()-resetTime;    
    if (passedTime > delayAvoidance)   
    {
      println( " X seconds have passed! " );
      return true;      
    }      
    else {      
      return false;     
    }     
  }     
}