I’m late to this thread, but such a thing must be awful for you. Please be kind to yourself. Since nothing can be done for Maggie now, try to think how nice it will be to give another dog a home.
Thanks again to everyone for their kind replies. It helps. 
There’s another thread on this board now about what to do if you find a dog in someone else’s car. I encourage you to read it.
Oh my god I can’t even imagine. I’d be a basket case. I’m so sorry.
I’m so sorry to hear about your Maggie. I cannot imagine your pain; I’m tearing up here. 
How terrible, I can’t imagine how I would feel. I had an old roommate who had a similar situation occur when she acquired two new kittens. One randomly went missing, and she thought maybe he sneaked outside and put up flyers all over the neighborhood. She found him a few weeks later, inside the large tupperware container she kept odd things in under her bed. Apparently he had climbed in while she was moving things around and suffocated :(:(
She was devastated, and I was devastated for her. I have to go snuggle some kitties now. :(:(
I’m so sorry this happened to you. It’s very easy for others to judge, but we’ve all had moments of inattention, most of us are just lucky the consequence wasn’t devastating.
Just one comment on your followup:
Your can get seat belts for your dogs. They are not terribly expensive and in the event of a car accident they could not only save your dogs life but yours too. Any unrestrained item in your car is a hazard in an accident a medium to large sized dog is on going to weigh more than most of the items in your car.
Fine Print, I am so sorry. I could only get about half way into it. Being a dog owner and reading the description of the chewed things and her curling up on the floor under the drivers seat was too much.
I wish you strength as you deal with this. Hopefully your posting is a reminder that helps another avoid the tragedy you have suffered.
I don’t care if this is a zombie thread, I was crying in front of my laptop reading it. I hope things are better for you now, FIne Print.
I missed this thread the first time, but I did want to say I’m sorry for your loss.
A tip given on an Oprah show about a woman who left her baby in the car for hours on a hot summer’s day, with the ultimate tragic result: When you have a pet or a child in the car, please put a shoe on the dashboard and do not remove it until the child or pet is out of the car. It could save their life!
Thanks to all who have replied and read this thread.
Since the thread’s been bumped, I thought I would convey some good news.
We have adopted another dog. Her name is Chelsea and (from what we can tell from the limited information the shelter had for us) she is either a flood or tornado rescue dog from the disasters earlier this year. She is a young Tibetan Spaniel (a ‘tibby’). I’ve never heard of the breed before but I’m very charmed. Our remaining dog, Bella, has bonded well with her (heck, so has the cat!) and the pets are all doing well. My Dad, who was the most hit by Maggie’s death, is also utterly enchanted by this new arrival.
As it turns out, with my parent’s health troubles plus the brutal Texas heat, we have not walked the two dogs at all. They wear each other out with playing. But in the fall, my parent’s health should be better and the weather cooler. So the question is, how do my family make sure this doesn’t happen again? I can understand how anyone reading this could be worried that history might repeat itself. One dog has already died on our watch, how can we dare to risk another?
The truth is, I don’t know. There is no foolproof product that I can find (at a price we can afford, police K-9 units usually have a device that costs about $700) that will warn of a dog in a hot car. There are (Thank God) alarms that will warn of a baby in a hot car (they are alarms that attach to the baby carrier and scream if the signal device [carried by the parents in a purse or pocket] gets too far away).
My honest thanks to all of the people who have suggested tricks to remember the dogs in the car. But some of these tricks require using your memory, which is the root of the problem. In short, if you remember the reminder, you have probably remembered the dog. And if you forget the dog, you will probably forget the object or clue you left to jog your memory. I’m not complaining by any means. I can’t think of any better idea. Leaving a shoe on the dash is one I have not heard though. Thank you, Annie-Xmas.
I truly believe that, having gone through what we have gone through, it is damn near impossible for us to forget another dog. But such complacency is what led us to this horrible situation.
Again, I am writing this to show that some good has come from bad. But also to hope that our story sticks somewhere deep down in those who read it so that they are that much more less likely to forget their own dogs.
Thank y’all again for your kindness.
Some Helpful Links (some examples, far from a complete list)
Heat alarm for dogs: http://www.criminalisticsinc.com/products/hotdog/hotdogplus.htm
Heat alarm for babies: http://sistersofinvention.com/child_products/readch.html
Seatbelts for dogs: http://www.vkrpets.com/safety%20harness%20(2).html?gclid=CIKjjseu7qoCFSQBQAod424ONw (good suggestion, Moonlitherial)
Ditto
How about you buy a neon cat collar with a big bell and attach it to your steering wheel when the dog is in the car?