Want an economically vibrant Complete Street?
Transforming those ugly 5-lane or 7-lane suburban “Stroads” into walkable boulevards is a lot more possible than it used to be, thanks in part to what we call “Place-Making Alternative Intersections.”
Engineers want to reduce congestion. Planners want to create walkable Activity Centers. If one side wins, the other side loses. Place-Making Intersections create Win-Win: They reduce traffic signal delay, which opens opportunities to calm traffic without causing A to B drive times to increase. Some designs actually reduce the pavement required for managing vehicles, making room for cycle-tracks and street trees.
The result? You can “drive slower, but travel faster” (and safer) through a fantastic mixed-use district. Win-Win!
If you need to reinvent an ugly Stroad, but traffic engineers are worried about congestion and travel times, this may be exactly what you need.
What can you learn here?
Traditional large suburban intersections have 4-phase signals: 1) EW through lanes; 2) NS through lanes; 3) EW left arrow; 4) NS left arrow. Alternative Intersections involve strategies to improve signal efficiency by handling left turns in some other way. This site focuses on designs that achieve 3-phase or even 2-phase signals, (making engineers happy), but the same designs can also be used to reduce speed limits and reclaim pavement from cars for Complete Street features.
There are three basic “Place-Making Families” of Alternative Intersection designs explored here: 1) Quadrant Intersections, 2) Thru-Turns (which encompass Median U-turns, RCUT/RCI, Bowties, and roundabouts), and 3) One-Way Split Intersections. See links to these topics below.
Quadrant Intersections
Quadrants redirect left turns to secondary intersections where traffic is easier to manage using a backway path. Since former left-turn lanes are no longer needed, they can be converted to planted medians, pedestrian refuge, whatever you want!
Thru-Turn Intersections
“Thru-Turn” is a catch-all phrase for designs with names such as Median U-turns, Bowties, Restricted Crossing U-Turn or Intersection (RCUT/RCI), and even roundabouts. The idea is to convert left-turns into “Right-U-Thru” or “Thru-U-Right.”
One-Way Split Intersections
One-way streets are often criticized as bad for walkable development. Maybe so in historic downtowns, but when it comes to retrofitting huge suburban “Stroads” – it is hard to find a design with more to offer to struggling retail areas. It is often possible to convert a single huge arterial into two one-way streets, where each is narrow and people friendly: slower in maximum speed, but faster in A to B speed due to less signal delay.
- One-way Intersections, Pt 1 (Walkability advantages, relative to Stroads)
- One-way Intersections, Pt 2 (Examples, both existing and proposed)
- StrongTowns: Are One-Way Streets Really That Bad?
- StrongTowns: Can One-Ways be a Middle Way for the Suburbs?
- Download pdf: Top-10 Advantages of One-Way Couplets
- Download pdf: Top-10 Arguments Against Couplets, Addressed
- TownCenterIntersections.org
Use StreetPlan.net for Free!
StreetPlan.net offers free tools for “rightsizing” arterial streets, including the cross-section design tool shown below. The tool uses “red / yellow / green” to guide you through context-based best-practices for walkable streets supported by the Institute of Transportation Engineers, Congress for New Urbanism, and National Association of City Transportation Officials (ITE, CNU, and NACTO)
