#define PIN_RED    5 
#define PIN_YELLOW 17 
#define PIN_GREEN  16

#define RED_TIME     1000 
#define YELLOW_TIME  1000 
#define GREEN_TIME   1000 

void setup() 
{
  pinMode(PIN_RED, OUTPUT);
  pinMode(PIN_YELLOW, OUTPUT);
  pinMode(PIN_GREEN, OUTPUT);
}

void loop() 
{

  digitalWrite(PIN_RED, HIGH);   
  digitalWrite(PIN_YELLOW, LOW); 
  digitalWrite(PIN_GREEN, LOW);  
  delay(RED_TIME); 

  digitalWrite(PIN_RED, LOW);   
  digitalWrite(PIN_YELLOW, HIGH); 
  digitalWrite(PIN_GREEN, LOW); 
  delay(YELLOW_TIME); 

  digitalWrite(PIN_RED, LOW);   
  digitalWrite(PIN_YELLOW, LOW); 
  digitalWrite(PIN_GREEN, HIGH); 
  delay(GREEN_TIME); 
}