One of the biggies that affects the usefulness of public transit for the elderly and disabled and simple sidewalk access. The transit agency has no control over the quality of the sidewalk or even the bus stop amenities in many cases. In Santa Cruz County, California, happily, we have a group meddling do-gooder seniors and disabled advocates who have identified high priority sidewalks that they need to get to their bus stops along with the correct jurisdictional contacts so they know who to bug. The transit agency for our county participates in grant funding applications with the appropriate jurisdiction to fix these accesses. This reminds me of another transit access issue which transit agencies have no control over, and that's the practice by many cities to bury bus stops in snow, since plows shove the snow to the side of the road and onto the sidewalk. Transit users absolutely should call the city and complain loudly about this practice.

This looks interesting, but it doesn't seem to work for me using either Chrome (35.0.1916.153 m -- up to date) or I.E. (11.0.9600.17126 also up to date) on Windows. I get the "choose a city" dialog, accept the San Francisco default, press "Start" and ... nothing happens. Looking at the Javascript console, it appears the mapbox library might be broken (or perhaps has an invalid key for whatever service it uses?). The error message says: "Unable to geocode city. Womp Womp. undefined" followed by: "Uncaught TypeError: Cannot read property 'geometry' of undefined"

@Jack: Commute times are available from the US Census Factfinder app. Clikc here and modify the Geography tab if you'd like to see different cities. I used Metro areas to compare Portland/Vancouver vs Houston, which shows 25 minutes vs 28 minutes commute times for workers who don't work at home. I also included San Jose CA because that's my town. If the link to the Census website doesn't work, I captured a screenshot here. I'm sure someobody has broken this down by ZIP code and created a map to show this in graphical form.

I guess I've assumed traffic projections are based on *some* kind of real world experience. Are they designed on models created in the 1970s or something and never updated since then?

Good stuff. Perhaps worth mentioning that sharrows can sometimes be placed incorrectly in the gutter zone, depending on jurisdiction.

The only "DIY" skirt guards I've seen are crocheted jobs that you hook to the rear fenders with clips, like the ones available from http://www.simeli.nl/

I just noticed this says in California. It looks a lot like the railroad I sometimes bike on, though without the fancy outrigger. http://www.flickr.com/photos/bike/3318007572/

Yeah, almost always on abandoned track. I have a friend here who goes exploring like this through southern California and Arizona. It's a special thrill biking over a deep canyon using an unmaintained railroad trestle bridge.

@awyllie hints at this, but it's the reason planning is often closely tied to cycling promotion. Conversely, our historically low gasoline prices encouraged development that took advantage of those low prices. Our collective spendthriftness is catching up to us now.

Urbana used the BMX stem and handlebars to get some front-back and height adjustability, rather than going with replacing the stem. Yeah, it seems a little clunky, but it works.

I agree regarding high risk (fast cycling on a road ride, mountain biking) vs low risk (trip to the corner store). That short trip to the store in a car still has the risk of head and bodily injury associated with speed. 35 MPH might seem like a crawl in a car, but that's almost insanely fast for most people on a bicycle; Mark Cavendish's finish line speed in a winning sprint is scarcely higher than that.