They certainly are! I guess alduin is just trying to burn some calories. Time travel makes one quite out of shape I suppose. Resetting my ps3 didn't help, but starting from the beginning again is not a big deal at thi point. It would've been hilarious if the headsman would've done his job. --- Vie Victis!
Alduin learned from the other thousands of players that if he shows up a few seconds later, He wouldn't have to deal with a Dohvakiin.
I also heard about a glitch where the carriages do weird stuff. They break off their normal path and fall off the side of the mountain; the horse glitches out and starts swinging around randomly; etc. --- PSN: VT-14 Skyrim PS3 Troubleshooting Guide --> http://www.gamefaqs.com/ps3/615804-the-elder-scrolls-v-skyrim/faqs/65084