December 1995
Hubert van Hecke

The traffic situation on Don Diego has emerged as one of the central problems of the Don Diego neighborhood. High speeds, the dangers of crossing on foot, and the sheer volume of the traffic have come up as major concerns at all of the meetings of the recently reconstituted neigborhood organization.

In this note I would like to offer a 'European' perspective on the problem. In Europe, no less than in the US, the car is king. However, when a community decides that enough is enough, and that it is time to take back streets for pedestrians and bicyclists, the measures taken are usually more far-reaching than simply putting up stop signs.

To illustrate this, I took some photographs of solutions to traffic problems in the towns of Meyrin (Switzerland) and Saint Genis (France), where I spend a fair amount of time each year. In Meyrin, there is a road that passes behind some high-rise residential buildings at the edge of the town (see photos Meyrin 1-5). The road is meant as access to the parking spaces behind and underneath the apartments. The road separates the apartment complexes from fields and woods where children play and people go for walks or runs. Unfortunately, this road is also a cutoff for traffic that has no business there, but only wants to avoid the main route, which has a stop sign, a traffic light and a traffic circle on it. I used to take this cutoff myself. This road is similar in length to Don Diego, and has the same width. The speeds on this road used to be quite high, as it had a long straight section, as does Don Diego. This year, the problem of fast, non-local traffic had been attacked in a simple, effective way. As shown on the photographs, raised beds of shrubbery and other small constructions have transformed the road into a course that was impossible to negociate at the former high speeds, and it effectively made it useless as a cutoff for non-local traffic. I only used it one time since these modifications were made. click on the pictures to enlarge them

The photographs from St. Genis show the approach to what used to be a difficult intersection (see photos St.Genis 1-2). This used to be where a sideroad joined the main street. The main street was straight and fast, making it difficult for the side-road traffic to enter, and dangerous for pedestrians to cross. Now, on the approach to the intersection, there is a 2-foot section of cobblestones which raises the road level to that of the sidewalk. There is also a change of color of the asphalt. The cobblestones form a speedbump, though not a severe one, but the visual effect of the bump plus the change in pavement catches the attention of drivers and is very effective in slowing down traffic. In addition, the fact that at the actual center of the intersection the road surface is level with the sidewalk makes it an intersection that is friendly to strollers, wheelchairs and the like. Another technique which effectively slows down traffic is to make the road look narrower than it actually is. A two-lane street with raised planters right at the curbside 'feels' a lot narrower than the same two-lane street with only flat white lines on it. click on the pictures to enlarge them

In the accompanying sketches I have applied some of these techniques to Don Diego. Figure 1 shows the current situation at the intersection with Camino de los Marquez. Each of the arms of the intersection is about 35' wide. This is a considerable distance when fast traffic is pitted against a non-fleetfooted pedestrian. Figure 2 shows a modified situation where the traffic is encouraged to slow down with a bump, a narrowing of the pavement and a change of surface. Figure 3 shows a perspective view of such an approach. The distance that pedestrians have to cross has almost been cut in half. In this situation, a 4-way stop might not even be necessary. Figure 4 shows an alternative arrangement. The pedestrian crossing distances have been cut in half, but I believe this solution does not tend to slow down traffic as much as in fig. 2. At the near-crossing of Lucero/Adela, a bump and pavement change might be sufficient to slow down traffic at the midpoint on Don Diego (see figure 5). Note that putting stop signs there might be problematic, since it is not very clear what the right-of-way rules are at this almost-but-not-quite-straight crossing. To attack the problems at the entry to Don Diego at the Cerillos end, the best solution would be to move the entry to the former location, such that Don Diego does not line up with Guadelupe. This may be unrealistic in the short term. Instead, narrowing the road, and increasing the sharpness of the s-curve would effectively slow down traffic there (see fig. 6). As it is now, there is so much space there that cars can accelerate considerably even before they exit from the s-curve. Along the length of Don Diego, we may employ devices as shown in the photos from Meyrin, to make the strees effectively no longer a straight shot (fig. 7) In addition to improving the traffic situation, these measures also make the street look more attractive.

Fig.1: current situation Fig.2: one solution Fig.3: perspective

Fig.4	Fig.5	Fig.6	Fig.7 ???
Fig.8