Thinking of allowing Seth on a yellow bus for field trip.

I was going to say no as he is 5 and only 36lbs, his class is going to the Planetarium. I then realized the Planetarium is literally right outside the base gate closest to his school. SO the bus will be on post for about 3 min driving 25-40 MPH then it will leave post go over and down a bridge and driver about .02 miles at 35 MPH then turn right into the college and drive about .03miles at 20 MPH on the college grounds.

Sorry for all the details but I want them there so you can get just how close it is but I need reassurance because well I know the dangers of a child under 50lbs and smaller than a 5 yr old on a bus.. So ummmm tell me it will be okay.

I would personally do it, but ds rides a yellow bus daily from his preschool to his daycare. ...It's something I do worry about, but I have no other choice at the moment since I work and go to school. His bus ride never has a speed limit over 25mph and it's 1mile away from each other with about 5-6lights, so the bus doesn't have much time to reach a higher speed limit.
However, when his daycare takes field trips "never farther than a few blocks, just far enough to not be walking distance and to many streets to cross - otherwise they walk places" they have their own BIG VAN and they carry a Booster out for each child and Booster them. I of course would like ds to be harnessed, but I think taking these measures are nicer then the alternative. Some kids at his daycare are tiny though.

When ds first started daycare/preschool and the trip in between his daycare told me to feel free to call to check in to see how ds was doing as much as I wanted. This is exactly what I did to, Maybe you can ask his teacher if you could call and see how things went/are going? Just to ease your mind. Let them know this is his first yellow bus trip and you are just a little worried.

I would do it. I understand the child is less safe than a bigger child on a bus, but is the child less safe than in a car? Enough less safe to make a realistic difference? And you wouldn't think twice about driving him there yourself.

I guess I was hoping some people who feel his I do about buses would chime in and give opinions.
Thanks for trying, really but I know how compartmentalization works and he doesn't meet the guidelines to be adequately protected on a bus and I won't feel ok with it until he does.
Really though thank you.
I will probably let him go though b/c it is so close. Any further would not be an option..