The Case For Good Road Design

Long time readers have heard me talk about engineering, enforcement and education; what I call the three Es of bicycle friendliness. My overwhelming belief is that all three are required to create truly bicycle friendly places.  Think of a tripod with telescopic legs.  Extend two legs but not the third and the whole thing falls down.  It’s like that with bicycle friendliness, too.  You need all three.

Of the three, the one I devote the least amount of time to in my writing is engineering infrastructure.  There are a number of reasons for this.  Probably most importantly, I’ve met a lot of advocates and organizations who focus exclusively on engineering.  They do a more than adequate job of covering it.  Secondly, I’m not a highway engineer.  How to build safe roads for all users is not my area of expertise.

That said, I am a road user and I know what works for me.  Interestingly enough, it doesn’t seem to matter which mode of transportation I choose.  There’s usually one street design that’s a clear winner and it’s the same design whether I choose to move around on foot, bicycle or by car. Let me use two pictures to illustrate an example.


Main Street, downtown Salt Lake City looking south from the skybridge in City Creek Center.

Illinois Street, Indianapolis from the Artsgarden looking north.

Illinois Street, Indianapolis from the Artsgarden looking north.

These two streets are virtually identical in many respects. Both bisect the urban core of major cities.  They’re approximately the same width so they have the same theoretical capacity.  Speed limits are similar (20 mph on Main, 25 mph on Illinois). That said, they could not be more different in terms of engineering.   The primary differences include:

  • One way (Illinois) vs. two way (Main)
  • Extensive (Illinois) vs. limited (Main) vehicle parking
  • Sharrows (Main) vs. no bicycle (Illinois) accommodation
  • Transit (Main) vs. no transit (Illinois)

So what do you think based on the pictures?  Is there a clear winner in terms of bicycle friendliness?   If so, which street would you feel more comfortable cycling on?

I’m familiar with both of these streets as a motorist, pedestrian and cyclist.  I can use either one, but there’s no doubt I’d rather be on Main.  Here’s why.

  1. The average speed on Main is about the same as the posted limit of 20 mph.  This makes sense since there’s only one lane each direction and there are a lot of bicycles.  Motorists have no choice but to wait on cyclists.  In spite of this, there’s very little congestion here.  Intersections clear and there’s general order.  The average speed on Illinois is closer to 40 mph, sometimes faster if traffic allows.  Motorists can change lanes to gain an edge and many do.  Congestion is about the same.
  2. Cyclists who want to turn left can easily do so off of Main.  On Illinois, we have to navigate three lanes of fast moving traffic to legally make our turns.  Even with the presence of light rail, Main is still easier for bicyclists to navigate.
  3. Illinois has door zones on both sides of the street.  Very few motorists expect to see cyclists here.  To be safe, we have no choice but to take the lane but there are no signs or warnings to motorists to expect to see us in their space.

Engineering doesn’t necessarily mean protected bicycle lanes or sidepaths.  In many applications, shared pavement works just fine.  I’m a big fan of this approach.  We simply don’t have the resources nor does it make sense to give each road user his or her own private space that sits empty most of the time.  We need to learn to share better…to utilize scarce resources to the benefit of all road users.

Even more importantly, when we share roads in intelligent ways, we begin to change the culture that still seems to think that bicycles don’t belong on the street.  I cannot emphasize enough just how important this is.

When we think of shared streets, we often think of quiet side streets that see very little traffic.  Main Street shows us two things. First, that shared streets can be busy arterials in the heart of the city and two, engineering done well makes all the difference in the world.


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