The Biking on Google Maps feature is a hot topic on cycling blogs (like this one), and on Twitter these days. This has been a long time coming, and many people are undoubtedly excited about the possibilites this brings.
I've looked at it, and wanted to take a moment to talk about my opinions of it.
First thing you see when you pull up the site: www.google.com/biking a map with bike paths (dark green) and bike friendly roads (green) highlighted. Just from what I know of Salt Lake city, I think the bike friendly roads are both roads with bike lanes, and frequently traveled routes.
Now, I am aware that it is only a "beta" version, and therfore will hopefully get a few revisions before they release the final version. Since the announcement last night, I haven't had a chance to enter in an unknown route and go out exploring (work and Utah's fith season "sprinter" are getting in the way of any quality outdoor riding right now), so I plugged in a familiar route that I take when I bike in to work.
Just like with driving, you get your route highlited on the map, with turn by turn directions and an estimated travel time. It appears that they are basing the estimated travel time at about a 12 mph speed. It also gives you an alternate route that you can select.
Like I said, I have made this trip by bicycle several times. There are a couple things I found interesting about the route(s) it provided.
First off, in several instances, It instructed me to diverge off of through streets, and routed me through residential neighborhoods.
For example, I needed to get from 1300 E to 900 E. Instead of just having me make a left turn on some street, then right on to 900 E, it routed me through several neighborhoods.
In another instance, It had me off of a road with a good bike lane (700 E) and instead put me on 600 E - another small, residential road, which goes directly into Liberty Park - and back out. Also, 600 E doesn't have a signal where it leaves the park at 900 S. which is a fairly busy road.
The alternate route it suggested is a major artery, which I don't usually travel on, as the cars are traveling above 50 mph, and there isn't any dedicated bike lanes on it.
Overall, it is a great addition to Google Maps. It does still need work, and with time, I'm sure that they will get most of the problems worked out. More than a useful tool to get you from point A to point B in an unknown city, it is an indication that bicycles are becoming more accepted in our society, and that is more valuable than any map.