The trucks don't leave until after the race starts. They make several announcements telling you how much time you have until the start so you can judge when to drop it off. They always hold one truck/van back for the people who completely miss the caravan.
Also, as someone who has both run the marathon and collected bags with the scouts at the start, here's some two top tips:
-Don't rush. It's not worth the stress. Double check that you have everything out of your bag that you'll need for the race. Give yourself plenty of time to drop off your bag and get to the start in time.
-Before you hand it in, make sure you have EVERYTHING (gel packs, phone, lucky talisman) you need for the race. Once it's up in the truck it can be impossible to find it again. It sounds crazy, because it would have just gone in there, but with hundreds of bags in the same spot, it's hard to fish it out again.
I am despondent, and turning to the friendly Runner's World forumites for help and support. I've been having major problems with my left foot since March, and after lots of visits with different doctors, several misdiagnosis and one VERY PAINFUL cortisone injection, my orthopedist now is fairly sure it is psoriatic arthritis. (All will be confirmed later this week). As I only just turned 38, I am considered quite young to be diagnosed with arthritis. (Though it is fun to joke about being arthritic and 38. Not.) I ran the FLM in 2005, and have been a runner since I was 12 years old. Has anyone else been diagnosed with this and continued to run? Will I be able to run again? If anyone has any experiences or advice to share, I would be most grateful. Thanks.
Well, Plodding Hippo, I hope at least you got a Good Luck from me and my sons. We moved over to the other side of the road when we saw that everyone was getting herded to that side until about 8:30 when there were so many people the road was flooded with runners.