To sum: A step in the right direction, but make sure to double-check things... and can Google really replace local knowledge?
It's no surprise that I not only enjoy my ride to work, but can usually make it in under 15 minutes (12 is my record, from a combination of really good luck with traffic lights and really pushing it). There's also a less adrenaline-worthy 20-minute version that I do when I'm not in any particular hurry, that takes me down the "Wiggle" to 14th St. to Townsend instead.
The existence of something like the "Wiggle" represents the sort of quandary in which I'd imagine anyone trying to make automated bicycle maps would be faced. The particular sequence of streets which allows for an easy traversal of the anticline which roughly divides the Western Addition from all points west is one of the first things any cyclist learns when he moves to San Francisco, but it isn't intuitive by any means.
San Francisco's street layout makes no qualms about its utter disrespect for the (rather dramatic) geography of the city (having been optimized instead for easy subdivision, sale, and development of property in a 19th-century boomtown), so cyclists take advantage of a bevy of local knowledge regarding how precisely to navigate the city's terrain without having a heart attack. No map will really make this obvious, though the SF Bicycle Coalition has done their best job by producing a map which not only has the "Wiggle" on it, but also color-codes every street by grade.
Still, bicycling has a certain DIY ethic to it, and learning to ride successfully seems to require one or both of a lot of trial and error, and being inducted into a local fellowship of cyclists who can tell you all the little secrets no map will ever show you. You can cut through this parking lot here! This street's a mess; take that alley. Swim upstream for half a block here, you can avoid a 6-block detour. Watch out for the drivers here. Etc. etc... Sometimes I think urban cycling requires its own form of "hobo signs":
So how good a job can a service like Google Maps do of giving acceptable bicycle directions? I decided to have them map out my commute. Here's what they spit out:
These are some interesting directions. Google's LatLong post about the bicycling feature makes note of how they've incorporated thousands of miles of trails and off-street paths into their maps. In this case, they're being a bit overzealous. Not only do they route me on a pedestrian path through Alamo Square, but it also terminates in a stairway. Meanwhile, there is a perfectly acceptable bike lane on Fulton St. immediately next to it:
It seems like a little further on, they're doing the opposite, and relying too heavily on directions for automobiles. San Francisco is currently engaged in a project to remake Market Street, which involves forced right turns for drivers at 6th St. and 8th10th St. The purpose of these turns is to optimize the street for public transit... and cycling. Google wants me to travel down 5th St., which is recently sharrowed as a result of the modification of the injunction against the Bike Plan (details at the SF Bike Coalition). That's all fine and dandy, but they want me to make a right turn on 6th, and then an immediate left into an alley, just to get to 5th St. As part of the Market St. plan, bicycles are allowed to continue on at each point where cars are forced to turn. I'm worried that Google is probably only relying on the directions for cars at that intersection. I've reported this to them as well:
All in all, these directions are a mixed bag. I actually decided to take the turn at 6th St, Stevenson, and 5th St. just to see if it were doable. It is, though I don't like having to merge across 6th St. to make a left turn (which I reported). However, despite that routing quirk, it's at least not a fatal flaw. Sending me down a stairway, however, is, even though I could probably negotiate it OK on the front-suspension MTB that I use as a daily commuter.
I'm sure Google will probably improve this service (it is, of course, in beta) to deal with some of the worse issues I've reported. I wonder whether automated bicycling directions will ever really replace local knowledge, though. I feel like I've passed some sort of trial by fire here in SF just by virtue of trying to get around a city whose geography and layout is designed to thwart you, and that some of that experience can't be transmitted or calculated or computed. Will all that trial and error and passing of advice be replaced by an algorithm? Time will tell. I worry that something will be lost if it does, but if the end result is that more cyclists are on the street, I think it will have justified the means. At some point, cycling in the US will have to shed its outlaw image... as much as I enjoy it, I also know that the true measure of safety is numbers.