Edge Lanes May Already Have the Desired Effect

Last Thursday [3/31/22], I encountered new lane markings on freshly resurfaced Evergreen St, part of my daily commute in Pt Loma. Surprised, I looked up details of the design now referred to as edge lanes, and started following news reports and associated discussion. Rather than a center stripe down the middle of the road to designate two way car traffic, they designate a center car lane with dashed bike lanes on either side. The idea is that cars travel down the middle of the road, and when approaching an oncoming vehicle, merge into the bike lane when safe to do so, or slow to fall behind a cyclist - a very similar maneuver to how cars regularly interact with me on Evergreen st.

One of the common fears voiced at community meetings or news interviews are of a head-on collision between cars. The roads generally selected for this treatment are residential, and carry a 25 mph speed limit. These are speeds chosen such that a driver has sufficient reaction time and braking distance if a child runs into the street, or a car blindly backs out of a driveway. If you were to encounter a car heading straight at you, what would be your reaction? Most likely to get out of the way, and/or slow towards zero mph. A collision between cars traveling at zero and 25 mph is not something anyone wants to experience, but thanks to decades of crash testing, a vehicle occupant would likely fare far better than the roughly 10% of pedestrians or cyclists that die when struck by a motor vehicle at 25 mph.

Does this fear reveal something we know about our residential roads but don’t explicitly mention? That people drive too fast and make it unsafe? We have a national epidemic, with pedestrian and bicyclist deaths rising approximately 40-50% over the last decade. Rather than ignore the underlying problem and hope that it will go away, or attempt to fix it through education or enforcement of speed limits, city engineers decided to try a new solution. They changed our perception of traffic flow using paint. Many people who are upset, in their calls to restore the previous road design, may miss the larger picture. Or if they don’t, perhaps they have different ideas on what could be done to address it. And this is where we should center our discussion - on how to best reduce motor vehicle speeds on our residential roads, and incidentally, roads like Gold Coast and Evergreen that service schools. 

It is clear that business as usual has not solved the problem, so we need to try something different. A review of edge lane roads in other communities in the US and in Australia, have concluded that this treatment reduced crashes by 44%. And this doesn’t include additional examples we can draw from Denmark, or The Netherlands, which developed their cycling culture through decades of policy decisions

As a cognitive scientist, I study perception, attention, and how we plan our actions. We smoothly navigate our environment by subconsciously predicting the future, hundreds of milliseconds at a time. We monitor how incoming sensory information matches our predictions, and adjust our movements as necessary, like an outfielder chasing a fly ball. It is startling and upsetting when we encounter a familiar scene that provides conflicting information: paint markings suggesting a one lane road where previously two lanes coexisted. This forces us to recalibrate our predictions and our driving behavior. Knowing we have to share space with other vehicles demands more attention. And humans are notorious for choosing to endure pain rather than perform a difficult mental task. But maybe a residential road demanding more attention is a good thing. 

So while the city pauses its rollout of the new street design, and we have time to learn about navigating edge lanes, let’s think about how we can make our streets safer for everyone, rather than rush to restore the previous street design. As I commented in the Mira Mesa Town Council meeting, if the changes lead to drivers slowing down, some of the desired effects may have already been achieved.

Upon completion of the western segment of W. Pt Loma this fall, biking options will look like this. Explore the W. Pt Loma + Sports Arena Blvd corridor in this google map.

Completion of the West Point Loma Blvd Cycletrack (eastern segment)

Looking west down W. Point Loma Blvd towards Adrian St.
Photo looking west down W. Point Loma Blvd towards Adrian St. showing some of the new 2019 bike lane striping.

Returning from scientific meetings and a holiday in July, I found the eastern span of the W. Pt Loma Blvd cycletrack completed (Adrian Street to Sports Arena Blvd). This is reason to celebrate. I’m personally happy because my partner’s daily commute to work is safer, and she already sees more bicycle and scooter riders on the track. As a community, Point Loma is one major step closer to having a fully connected bike way between Ocean Beach and Old Town Station. The San Diego River Bikeway currently connects these nodes, but for those that want to access the restaurants, breweries, businesses or neighborhoods between Old Town and OB, this new cycletrack on W. Pt Loma is a potential game changer.

Upon completion of the western segment of W. Pt Loma this fall, biking options will look like this.
Upon completion of the western segment of W. Pt Loma this fall, biking options will look like this. Explore the W. Pt Loma + Sports Arena Blvd corridor in this google map.

The new cycletrack offers slow and fast riders space to safely maneuver, and generally increases the visibility of traffic at intersections. Turning left across W. Pt Loma is easier than before in the stretches where there is now one full speed (35 mph) travel lane, rather than two, to reach the center turn lane.

There is still room for improvement in the westbound direction as riders cross from Sports Arena Blvd onto W. Pt Loma Blvd. Across the interchange, westbound traffic changes from two travel lanes and a bicycle lane, to two travel lanes with bicycle sharrows, until the street widens back to separated bike lane after clearing the southbound left turn lane. I was taught in driver’s ed to never change lanes within an intersection, and regularly encounter confusion between cyclists and drivers over how to merge through this intersection.

Corner detail of West Point Loma Blvd and Sports Arena Blvd

All in all, I enjoy this new W Pt. Loma route more than ever. I look forward to completion of the western segment so that I too can enjoy a safer daily commute. I often pass people or dogs walking in the new cycletrack, and with ample space to pass, it feels like the street is more accessible to all. The western segment will also improve Rue de Orleans and W. Pt Loma Blvd - one of the more dangerous intersections identified as one of the ‘Fatal 15’ locations where repeat fatalities occur. These ‘Fatal 15’ inform the city’s Vision Zero approach for targeted pedestrian safety improvements.


Help BikeSD bring safer streets for all San Diegans
Yes! I want to support BikeSD and their their advocacy work!