Letter from Chile: Observing the Effect of Design on Speed in Santiago

About ten years ago, Amanda (Jones) Eichstaedt and I took a one-week class called "Fundamentals of Traffic Engineering" offeredby UC-Berkeley's ITS Technology Transfer program. We were both at a place in our careers where we felt like we could not move progressive treatments for pedestrians and bicycles forward because we did not understand the language and philosophy that public works employees used to block us. Taking this class seemed like a good way to improve our understanding of traffic engineers. As we hoped, the course was illuminating and helped us to understand how traffic engineers are taught, what guides their decisions, and what may restrict them.

On the drive home Amanda said, "If I've learned anything this week, it is that it's all about design speed." We then went on to discuss how design is paramount for setting the speed people will travel and the safety consequences of a local neighborhood street built to allow speeds of 45 mph or higher.

This past month I have been in Santiago, Chile, and have thought a lot about design speed. This large metropolitan city has added many bike facilities in the last ten years. Mostly they are ciclovías, which are separated bike facilities, often in the place of a sidewalk. Historically the central streets of Chilean cities have had big, wide, beautiful sidewalks; now some of that sidewalk space has been converted to two-way bikeways in some areas. They are usually six feet wide, three feet per direction.

In addition to these ciclovías, there are some on-street separated (by paint or by raised pavement markers) bikeways, with the same six-foot dimensions. Riding on either facility is weird. It is hard for me to get used to riding on what used to be sidewalk space, and it is hard to cross at intersections. You have to go down one ramp and across the street and up another. This leaves a lot of room for unexpected clashes with pedestrian or automotive traffic.

Watching everyone else ride, I see a variety of behaviors. Least surprising is that where there isn't a ciclovía, people ride on the sidewalk anyway. It is exactly what one might expect: They have been told to ride on what is virtually the sidewalk, so that is what they do. People do ride on the streets, a bit, but Chilean streets are very narrow (typically less than 10 feet) and riding in the street really only works well on the very wide (20 feet plus) bus lanes.

With much less room to maneuver in streets and bikeways, everyone drives or rides a bit more slowly. Also, because there are many cyclists and they cross at many intersections, it is never clear when they might pop up. This seems to slow down traffic a bit, or at least make drivers more defensive. The narrower two-way bikeways make it difficult to pass other cyclists, and (as is typical in the U.S.) some riders are much more aggressive than others--which can be scary. Unsurprisingly, I have seen a bit of conflict between pedestrians and cyclists. People here walk on every street and they don't want to be hit by a roving cyclist. I imagine the city has fielded many complaints about the ciclovías and how they have changed sidewalk traffic patterns.

I have not taken a hard position on whether or not Santiago has made a mistake with very narrow, sidewalk-ish bikeways, but I do see that the somewhat clunky design has forced everyone to slow down. Yes, Amanda--it's all about design speed.

by Carolyn Helmke