Really, do you need 107 reasons?
Well, here's a good reason not to commute by bike in Beijing. If you happen to be travelling home from work in a bike lane next to, oh, let's say, a lady on a small motorcycle, and she happens to swerve into you, she might knock you off your bike. She might even land, along with her motorcycle, on top of you. You might extricate yourself from the pile to discover you're losing blood at an alarming rate. Also, you'll realize there is no ambulance service. So you'll call the Embassy, but it'll take 40 minutes for them to find you there by the side of the road. It'll take your spouse that long to find you, too. Maybe she could've gotten there faster but, you know, she probably had to find a neighbor to come over and sit with the kids. So, even if you're lucky enough to crash on the same street as the hospital, it'll be well over an hour before you get to the ER. You'll need stitches. Lot of stitches. Inside of your face and out. And you're likely to be pretty bruised and cut up and sore. Maybe you'll even have some nerve damage if you hit your shoulder particularly hard. Also, your bike will be mangled. Which is okay, really, because at this point you really ought to give up commuting by bike, don't you think?
(p.s. Bart's doing much better now.)