N.,
My favorite development book [i used to teach teachers], Touchpoints, by T. Berry Brazelton, M.D.talks specifically about this in the 18-month-old section of the book on page 165, "Today, many parents of toddlers are away at work all day.When they return at night, they dream of a loving reunion.Often they don't get it.A healthy toddler will save up all her most intense feelings for them.Parents who are at work all day come home to--or pick up at child care--a baby who has been waiting all day to break down. When she sees them, the toddler may let it all go...Professional caregivers are rarely presented with the same passionate disintegration that parents are greeted with."
This is because your child feels safest with you and as such wants to meltdown with your love and support. I know it doesn't help with your dilemma but I thought it might console you a bit to know that this behavior is completely normal and appropriate for your child's age.
I too was going to suggest giving a snack in the car...if hunger is a component in the meltdown, a snack might help it be less dramatic. Another idea is to ask the child care facility to give him a snack late in the day...maybe you can provide the snack if they are resistant to the idea.
Another suggestion I have for you is to form a night time routine that is the same everyday from the time you pick him up until the time he goes to bed. For two to four weeks do it EXACTLY the same way, until you feel he gets it and knows what is coming next...do the routine in the same order each night, around the same time each night and start talking about what comes next a few minutes before you change gears. This will give your child a chance to anticipate what is coming next and prepare himself for it. After a few weeks you should notice an improvement in him. Once he understands the routine you will be able to deviate from it once in while and as long as you let him know 10-30 minutes in advance, he should be fine. At this age consistency is REALLY important. They need to feel in control of what is happening and by setting up a routine you can provide that sense of control for him.
I'm a stay at home mom so our night time routine starts when Daddy gets home from work...and on most days it's the same...play with and then go upstairs with daddy while he changes clothes [10-15 minutes], eat dinner together and talk about our day, play with daddy and mommy [5-15 minutes], bath, pj's, books, tv in mommy's bed [we tivo Wonder Pets and watch one episode every night] then time to sleep. my husband does the bath, pj's, and books alone, i usually come up and lay in bed with them for tv time and then i walk him to his room abd put him in the crib. my son is not quite 23 months old and he starts climbing off my bed to walk to his room as the episode of Wonder Pets is ending, without any prompting.
I tell my son the next three big things that will happen in our day, throughout the whole day in order to prepare him for transitions. So, when he wakes up I tell him we are going to have milk, then change diaper/get dressed, then go downstairs. While I am getting him dressed I tell him we are going downstairs next, we can play with toys for a few minutes then eat breakfast...during breakfast i tell him the three big things we will do between then and nap time...usually a class or errand, lunch and nap. During lunch I tell him what is going to happen after nap until Daddy gets home...you get the idea! Anything that is really different in the routine that day gets talked about a bunch throughout the day. It works well for us.
I know this is really long...hopefully you got something out of it! Good luck.