Cook macaroni according to package directions for al dente pasta. Drain and place into a large bowl.
While macaroni is still hot, add vinegar, carrot, celery and onion. Mix together until combined.
Cover macaroni and place in refrigerator for 15 minutes, or until cooled.
In a medium size bowl, combine mayonnaise, half and half, brown sugar, salt and pepper. Mix until well combined.
Add mayonnaise mixture to the macaroni mixture and gently mix together until all macaroni noodles are coated in the dressing mixture.
Cover and place in refrigerator for at least four hours. If possible chill overnight prior to serving.
If needed after chilling, a tablespoon or two of additional half and half can be added to Hawaiian Macaroni Salad to achieve desired texture.