by Wade Walker, Regional Engineering Manager, Alta Planning + Design

MLK_Two_WayCities are continuing to explore avenues (pun intended) to revitalize their downtowns and benefit from more vibrancy, including a more walkable, 24/7 atmosphere.  Many of these cities were saddled with one-way street networks “back in the day” when the daily M.O. was for Joe Commuter to drive into his downtown office from his house out in the suburbs, and then get back as soon after 5 pm as possible.  By having these one-way systems, cities could pump significant volumes of cars into downtown and then discharge them back out quickly.  Two things have changed significantly since then that render many of these one-way networks obsolete. First, downtowns are being rediscovered as a desirable place to live, and they have things to do after 5 pm.  Second, the interstate system was created starting in the 1950’s, which has supplemented (and sometimes supplanted) the role of one-way systems in moving traffic into and out of downtowns.  So there is a lot of opportunity to consider converting a lot of these systems back to two-way.

A few important points to consider if your city is considering a conversion:

  • Healthy congestion is OK in successful downtowns.  Nobody wants to sit on a street that resembles a parking lot.  However, many downtowns have an advantage over their suburban counterparts since there is usually a dense network of streets and redundancy in routes.  If you’re considering a one-way conversion, expand your traffic analysis to take into account the entire network, not just the subject street(s).
  • Two-way streets are much friendlier to the occasional or first-time visitor.  Not much is more frustrating to a first-time visitor than trying to get to a destination downtown and being continually shunted away due to one-way streets.  Recirculation of traffic results in increased VMT (equaling more emissions and pollution), increased turning movements (resulting in greater probability of accidents), and increase driver frustration (resulting in a first time or occasional visitor making a decision to not come back).
  • Visibility is key to commercial success.  On a one-way street, not all frontage is equal; the downstream corners are invisible to drivers since they are actually behind the moving car as it goes through an intersection.
    Retail Eclipsing

    Retail Eclipsing

    This “retail eclipsing” as shown in the diagram is a very real characteristic of a one-way street—if two-way traffic is allowed, each and every corner has the same potential to be seen and patronized.  Rectifying this disadvantage is one reason why cities like Chattanooga and West Palm Beach have seen retail vacancies on former one-way corridors virtually disappear in the years following the conversion.

  • Speed kills…literally.  The comfort of walking or cycling in a downtown is directly related to the speed of the traffic moving along the corridors.  One-way streets often have excess capacity, and the ability for aggressive motorists to pass slower moving vehicles by “slaloming” results in vehicles moving faster than they should in a downtown context.  Two-way streets often prevent this type of behavior and result in slower-moving traffic which is more in line with pedestrian and bicycle activity.  Keep in mind that if you think of downtown as a destination, there is no need to move cars as fast as possible once that destination is reached.  It’s more important to focus on moving people, and not just cars.

In conclusion, many cities have had a lot of success in converting one-way streets.  But it’s important to understand that it’s not a silver bullet.  Simply changing the direction of the street will not guarantee economic revitalization; many conversions have come about as part of a comprehensive downtown revitalization plan.  However, not addressing the one-way issue can put your downtown at a significant disadvantage in achieving economic prosperity and walkability.

Wade co-authored a paper on the subject of one-way street conversions for the First Urban Streets Symposium in 1999; it can be downloaded and reviewed here:  One Way Streets in Downtown-Walker_1