"Narrower traffic lanes, additional turning spots and more bicycle paths" are some of the ideas Walkable Communities director Dan Burden suggests for Des Moines, according to an article in the Des Moines Register.
Once again, as I've stressed before, the presence of sidewalks isn't enough to make a walkable community - there needs to be an appealing streetscape to get people out of their cars.
Wide travel lanes encourage speeding, as well as making it more daunting for pedestrians to cross the street.
I strongly recommend taking a good look at these images from Walkable Communities of what makes appealing and non-appealing walking environments. It's a large image file but still worth the download even if you're on dial-up, just be patient. When it's in your browser, if you use IE, move your curser to the bottom right of the screen, wait for a little icon to pop up and then click the center of it to see the image full sized, then use your scross bars in the browser to see all the images.