For example, given two streets with speed limits of 35 mph, drivers on the one with a sidewalk average 34.7 mph. Drivers on the road without the sidewalk averages 42 mph.
One of the most interesting parts of this report is the effect of beauty on the speed of traffic. A line pulled from the report and highlighted on the Tom Vanderbilt Traffic blog—
The aesthetics or “beauty” of a road environment has also been investigated in relation to traffic safety. Drottenborg (1999) studied the impact of speed on streets that appear as “beautiful” due to the blossoming of cherry trees along the streets in Lund during springtime, and similar streets that lack such beautification. She found that the free-flow mean speed decreased by about 5 percent and the number of vehicles traveling at high speeds between 50-60 km/h decreased by about 12 percent during the cherry blossom period.
That's pretty awesome.
And I know it to be true. I definitely slow to an amble down streets like Montview when the leaves are starting to change.
Of course, there is an associated increase in the appreciation of your surroundings as you slow down. It allows you to stop and smell the proverbial roses. Or coffee. Or bacon. Or whatever it is you like to smell.
And I have to be careful not so succumb to modal bias here. You can see and appreciate more on a bicycle than you can zooming along in your car. But I've definitely seen and noticed things while strolling on foot that I missed while zooming along on my bike.