One-way street designations

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One-way street designations are policies that direct the flow of the street to be only in one direction. Streets that are designated to be one-way will only serve a traffic that flow in one direction and although reasons may be varied this policy is often implemented to accommodate heavier traffic on the road. [1] One way streets compared to two way streets have the advantage of providing faster traffic since there is less conflicting traffic flow. Also, the traffic flow is not interrupted since there are less stops because of low chances of crossing traffic. Therefore, one way streets are sometimes more preferred than two-way streets.[2] This policy may be applied to the street on its initial construction or after it has been built. One-way street designation policy can also be active at certain times of the day or certain days of the week, rather than being permanent, depending on the situation.[3] The functioning is facilitated by signage, road markings or present law enforcement on the street. One-way street designation of street could be implemented on a varied size of roadways, alleys, streets, avenues or boulevards can be subject of one-way street designation policy.



Conceptual Example

A state seeks to smoothen the flow of traffic in its cities’ roads,decrease congestion, wants to create safe roads in roads that are too narrow to be used as two-way roads or calm the traffic in historical centers. In order to accomplish these goals, the state adopts policies which allow the cities to designate their two-way streets to become one-way streets. The cities first make the necessary research in order to find out which streets need to be converted into one-way streets using transportation data, Then, the city may need to negotiate with the residents[4] or in case for larger projects with county and state and sign an agreement where all sides agree on the conversion of the road. The converted roads are then marked with necessary signage or road markings stating that the traffic flows in one direction. The roads are then maintained by establishing necessary traffic laws where drivers who break the laws of one-way streets would be fined. [5] Since the one way street does not need to have a median lane therefore provides more space and has less number of turns, the road can accommodate more cars which move at a higher speed which would solve the traffic problem in the city and also provide more curb parking spaces.[6]

Specific Example

In 1922, Greater Los Angeles Traffic Commission appointed a committee to investigate the possible area of uses of one way-street designation policy in L.A.. The main reason for the policy to be adopted was that it was argued that one-way streets accommodate 40% more traffic. Therefore, although the policy was tried to be adopted in 1937 and 1942, the policy was adopted in October 6th, 1947, which affected its 5th and 6th streets. From then on many other streets of the city was converted into one-way streets. First, 8 of the east-west streets converted into one-way then in 1953, 8th and 9th streets were converted. Later in 1956 and 1971 4 more streets were converted which the first three was for the construction of the Harbor Freeway. The conversions for the Freeway was done with agreement signed between city, county and the state. In the same year 2 other streets where switched to provide extra access for the new Convention Center. More recently construction for the Red Line became a catalyst for the new conversion of Figueroa, Flower, Grand, Olive and Hill into one-way streets.[1] The conversions would made by adding chapters about one-way streets to Code of Ordinances which allow the council to designate the new one way streets.[7]



Tradeoffs of implementing this policy may include:

  1. Residents inconvenienced by the one-way flow and oppose to it because of the reason that it will add more time and effort in trips in the direction which they can no longer drive. [4]
  2. Drivers that disregard the one-way sign and drive into oncoming traffic[8]
  3. Increase of parallel streets instead of cut-through traffic thus, instead of having one road that serves both directions, the neighborhood now has to have multiple parallel one-way roads that serve opposite directions. [4]
  4. Decreased safety for pedestrian road users due to drivers not looking at both sides of the street in case of pedestrians crossing on either side, thinking he/she only needs to look one way for traffic. [9]
  5. Potential decline in revenue of retail businesses, which may now only attract customers making trips in the direction of the one-way street. [9]
  6. Challenging navigation due to the layout of the streets[9]
Compatibility Assessment

Compatibility Assessment.png

If answered yes, the following questions indicate superior conditions under which the policy is more likely to be appropriate:

  1. Is the existing street network experience significant traffic congestion that increases trip times?
  2. Does the current street network cause any danger for pedestrians?
  3. Does the existing street network currently include primarily bi-directional streets?
  4. Is the existing street network result in an increasing rate of accidents per mileage?
  5. Would the designation of streets as one-way be able to occur without materially impairing the revenues of retail businesses?


Assuming that a jurisdiction has decided to adopt the policy, the following questions will need to be answered when determining how to implement this policy:

  1. How will the streets to be converted are going to be selected?
    1. Use of contemporary traffic analysis technologies to gather data from high demand roads.[10]
  2. How the newly assigned one-way roads will be introduced to the public and perceived by the driver?
    1. Publicly presenting the designations on legal papers and publishing them on a easily accessible and understandable website.[11]
    2. Designing and implementing the right signage as in one-way signs, white lane coloring, wrong way signs facing opposite directions.[12]
  3. How should the one-way street be designed so that it will be safe and efficient?
    1. By having previously tested and used design standarts as refernces and applying them according to the particular case. [13].
  4. How will the one-way road be maintained and the rules/regulations be enforced?
    1. New laws and regulations could be set up so that police may enforce them. For examples fines and credit reductions applied to drivers. [14] [15]
  5. How will the one-way road be displayed on contemporary navigation technologies or maps?
    1. A navigation application named Waze has an extended study about how one-way roads are displayed and designated on maps.[16]
    2. City of Toronto provides digital datasets for one-way streets that can be utilized by commercial mapping applications. [17]



  • For governance level(s): Local.









  • Two-Way Street Conversion.] Riggs W, Gilderbloom J. Two-Way Street Conversion. Journal Of Planning Education & Research [serial online]. (2016) 2016;36(1):105. Available from: Publisher Provided Full Text Searching File, Ipswich, MA. Accessed October 22, 2016. The results of this study shoes that traffic flow increased after implementation of two-way flow, but traffic accidents decreased. It also noted that other ancillary benefits, such as increase in property values and reduced crime. These results provide evidence that conversions can promote mobility, safety, and livability.
  • The economic and environmental effects of one-way streets in resident[ial areas.]. Kennedy, John. Hill, Dennis. (1970). Socioeconomic considerations in transportation planning: 75-79 , Available from: Highway Research Board. The study analyzes the consequences of locating one-way streets in residential areas the following were examined: (1) existing theory concerning agricultural location: (2) transportation and urban land use; (3) environmental preferences including noise; and (4) the role of the urban economy. Study then compares theoretical observations with actual conditions by selecting a one-way system or systems for case study and consolidate and interprets the results obtained from the theory and case study.
  • The Best-Laid Plans: How Government Planning Harms Your Quality of Life, Your Pocketbook, and Your Future.. O'Toole, Randal. (2007). The Best-Laid Plans: How Government Planning Harms Your Quality of Life, Your Pocketbook, and Your Future, Available from: Cato Institute. The book makes the case for repeal of federal planning laws and closure of government planning offices by defending the point that, thanks to government planners, American cities are choked with congestion, major American housing markets have become unaffordable, and the cost of government infrastructure is spiraling out of control.
  • Evaluating Urban Downtown One-Way to Two-Way Street Conversion Using Multiple Resolution Simulation and Assignment Approach. Chiu,Yi-Chang. Zhou,Xuesong. Hernandez,Jessica(2007). / JOURNAL OF URBAN PLANNING AND DEVELOPMENT: 222-232. ,Available from: ASCE. The article highlights the unique features in the methodological aspect and illustrates the considerable

benefits resulting from the proposed Multiple Resolution Simulation and Assignment Approach framework.



  1. 1.0 1.1 1.2 What's Up With That: Downtown's One Way Streets, Dakota Smith, March 11, 2008
  2. The Case Against One-Way Streets, Eric Jaffe, Jan 31, 2013
  3. 3.0 3.1 § 18-4004 One-Way Streets
  4. 4.0 4.1 4.2 4.3 4.4 SIGNAGE: ONE-WAY STREETS, City of San Antonio
  5. Syracuse, Indiana - Code of Ordinances, ARTICLE 5. - ONE-WAY THOROUGHFARES
  6. Evaluation of the One Way Street Alternative for Valley Road, Princeton Engineering Department September 2015
  7. Redding, California - Code of Ordinances, Chapter 11.04 - TRAFFIC REGULATIONS GENERALLY
  9. 9.0 9.1 9.2 3 REASONS TO TURN THESE ONE-WAY STREETS INTO TWO-WAYS, Rachel Quednau ,August 5, 2016
  10. Evaluating Urban Downtown One-Way to Two-Way Street Conversion Using Multiple Resolution Simulation and Assignment Approach Yi-Chang Chiu, Xuesong Zhou and Jessica Hernandez
  11. Syracuse, Indiana - Code of Ordinances, ARTICLE 5. - ONE-WAY THOROUGHFARES
  12. One-Way Signsand Sign Placement, Stephen Thompson and Patrick Wright, Pennoni Associates
  14. 39:4-85.1 Designation of One-Way Traffic
  15. 3.04.030 Designation of one-way streets and alleys.
  16. Determining one-way streets
  17. Data catalogue, One Way Streets, City of Toronto
  18. 18.0 18.1 18.2 Streets, One-Way, Christopher Miller
  19. Traffic Control Devices , City of Roseville
  20. Contraflow Bicycle Lanes on Urban Streets Cambridge, Massachusetts, Cara Seiderman
  21. Why one-way streets are bad for everyone but speeding cars, Emily Badger, April 17, 2015
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