(Photo from SDOT Blog)
Have you traveled on 35th SW and/or SW Roxbury since the recent rechannelizations (and other changes)? SDOT has just published its first report on the aftermath – see it on the SDOT Blog website, now that the work is mostly done. An excerpt:
… The project team has been monitoring the revised segments of 35th Avenue SW and SW Roxbury Street on a daily basis. We’ve also collected data in an effort to obtain preliminary insights into the effects of the recent changes.
To date, we’ve seen no change in volumes on 35th Avenue SW or SW Roxbury Street. Daily traffic volumes on these streets remain within the same range as pre-project volumes. During our public outreach process, some people commented that they were concerned about drivers diverting to nearby residential streets after the channelization changes. We’ve received no reports of diversions from residents and our volume data does not indicate diversions to residential streets. However, we will continue to keep an eye on this issue moving forward.
Our first look at vehicle speeds on 35th Avenue SW is encouraging. The street once commonly referred to as “I-35” in the neighborhood no longer sees the majority of drivers pushing speeds up to 40 miles per hour. Instead, most drivers now travel around 34 to 35 miles per hour. This is a significant improvement but we’d like to see drivers traveling at lower speeds which are closer to the new posted speed limit of 30 miles per hour. We will expand our speed data collection efforts in October and November and hope to see lower speeds as drivers adjust to the new conditions.
There’s no doubt that these corridors feel different than they used to, especially during the afternoon commute when traffic volumes are highest. With just one general purpose travel lane in each direction, vehicle queueing at signalized intersections is more substantial during the afternoon/evening commute period. However, longer signal cycles effectively mitigate the queues and vehicles are able to clear intersections in just one green phase. Occasionally, emergency response vehicles such as police and fire will preempt signals at SW Holden Street, so it can take up to two signal cycles to clear the intersection when traffic volumes are high.
Again, the corridor feels different but vehicle and transit travel times have been minimally impacted. During community outreach, we mentioned that traffic modeling projected delays on 35th Avenue SW of one-to-two minutes with a maximum delay of 2.5 minutes during the afternoon rush hour. Our travel time data, based on driving the 35th corridor dozens of times during peak hours, show that our models were a bit conservative:
The data tables are in the full post on the city website – with car and bus travel times – as are ways to get your feedback to the city.
P.S. If you missed the backstory on the 35th and Roxbury projects – check the links and slide decks in this story we published while the road work was under way.