At what age would you let your child go to school alone?

I don't have kids but after 8 years driving around the city I can tell you it really depends on where you live, if it's a safe neighborhood or not. most people I know let their kids go alone around 10 or 11 years old, but some wait until they're 12 or 13, it all depends on whether the kid is responsible and knows the route well. personally I think you gotta let them go eventually because otherwise they never learn to fend for themselves, but yeah, first you gotta make sure the route is safe.