The Dutch "Dueling One-Way"

Journey Abroad

It's been nearly a year since I visited the Netherlands, my first trip outside of the U.S. in over 10 years. One lesson that has stuck with me is the way residential streets can be quickly repurposed to increase safety and livability of their residents.

The quickest approach to reduce speeds is to simply restrict where vehicles can go. While biking around the neighborhoods of Utrecht, I found these signs that showed a stretch of road to a red box, with a notice below ("uitgezonderd") followed by the bicycle symbol.


Figure 1: A "dead end" warning sign with "Uitgezonderd" notice below (Utrecht, NL) 

"Uitgezonderd" in Dutch translates to "excepted," meaning this sign is a dead-end warning for drivers, with the exception of bicycles and scooters. At the end of the street is a single bollard that can be removed for emergency vehicles. This single bollard acts as a filter, where people walking and rolling can pass through. Certain cities in the United States employ this technique, often coupled with "Bicycle Boulevards," to ensure bicycles and people walking are prioritized along a shared automobile/bicycle roadway.


Figure 2: A colorful "Diagonal Diverter" that filters vehicles from people walking and biking. This strategy can be too blunt for some streets.

However, this strategy can appear too blunt in many cities where traffic engineers insist that a connected grid is essential for automobile travel, or that access must be maintained for emergency vehicles. What can be done when you don't want to completely restrict the flow of traffic?

This is where the Dutch have another tactic: one-way streets for automobiles, but two-ways for bicycles.


Figure 3: A "Do Not Enter" sign, with a notice "uitgezonderd (excepted)" bicycles and scooters. (Utrecht, NL)

By allowing two-way bicycle traffic on a one-way auto street, the access for residents and deliveries are maintained while the network for people riding bicycles is uninterrupted. This compliments the Dutch ideology that bicycling is simply faster walking. A sidewalk is not considered a one-way sidewalk, why people riding a bicycle be forced to treat the street as a one-way street?

So how can a network of one-way automobile streets with two-way bicycle traffic provide for a safe environment for all road users? Well the incorrect approach would be to simply take the typical street grid and alternate the direction of each street. Many urban downtowns operate this way as a result of traffic engineers optimizing traffic flow "through" the downtown core:


Figure 4: Simplified grid of continuous one-way streets.

By making each one-way street a continuous direction, a person riding a bicycle is going to have to maintain automobile speeds to feel comfortable. This defeats the purpose of making bicycling "faster walking," and ensures only the most able-bodied and fearless riders will feel comfortable riding (unless physical separation is installed). Allowing two-way riding would be unsafe unless there is dedicated space for bicycle riders to move "upstream," such as this contra-flow lane found in Corvallis, Oregon:


Figure 5: One-way shared bike/auto street with a contra-flow bicycle lane. (Corvallis, Oregon)

The "Dueling One-Way"

One alternative is to use "Dueling One-Ways" to alternate the direction of the one-way streets. By alternating the direction of the one-way street when it approaches an intersection, vehicles are forced to turn off the street while bicycles can maintain their direction:


Figure 6: Diagram of a Dueling One-Way (Source: RJ Sheperd)

The "Dueling One-Way" pushes vehicle traffic away from the bicycle priority route, potentially allowing automobile traffic to evaporate since it no longer provides unimpeded access for automobiles. Rather, automobiles are likely to use the main distributor roads to reach their destination. In our example grid, we have dueling one-ways at most intersections, include when a bicycle priority street crosses a larger two-way neighborhood collector:


Figure 7: Diagram of multiple "Dueling One-Ways" in a street grid (Source: RJ Sheperd)

The other benefit to this strategy is that it still maintains emergency access, which often comes at the expense of building All-Ages bicycling facilities.

So far the only place I have experienced "Dueling One-Ways" is in the Netherlands. We may find the first example of "Dueling One-Ways" in Portland, Oregon as part of the city's Northwest in Motion plan. Northwest Portland has some of the highest density neighborhoods in Portland, yet some of the lowest bicycle mode-share. Many of the bicycle priority streets are used as "cut-through" streets, making it stressful and inaccessible for many would-be bicycle riders.


Figure 8: Alternating one-way along NW Jefferson in Portland, OR. (Source: Northwest in Motion Draft)

Would the "Dueling One-Way" help reduce the stress of a bicycle boulevard in your town? Where do you think a series of Dueling One-Ways could make it safer for kids and older adults to walk and ride?