Recently, we reported on a letter from Caltrans to Supervisor James Ramos, in which a state transportation agency official said that Caltrans would not lower the speed limit in downtown Joshua Tree, despite recent serious pedestrian-involved accidents. A while back, we reported that another Caltrans official said he would look into the abrupt speed limit changes in the approaches to Joshua
Tree. Reporter Dan Stork followed up, and learned that change isn’t likely…
In 2014, on both approaches to downtown Joshua Tree on State Route 62, Caltrans replaced 55 mph signs with signs announcing an approaching 45 mph zone. In May of this year, we complained to Haissem Yahya, the Operations Manager for CalTrans District 8, that we thought the change was counterproductive and dangerous. He told us that a 20 mph step-down wasn’t supposed to happen, and he would look into it. We followed up with Yahya this week. He told us that he had relayed our complaint, and said that a change to a more gradual stepdown was in the pipeline. After that conversation, he checked on the status of the request, and learned that a change is not in the works, barring another speed survey, with different results. He learned that the reason for this is based upon a section of the California Manual for Setting Speed Limits (2012 revision) which prescribes rules for setting speed limits in transition
zones, and explicitly allows, and even requires abrupt speed changes in some situations. Here is a paraphrase of the Caltrans logic, based upon the rule book and official explanations: Caltrans wants to keep traffic moving. It uses speed surveys to determine existing driver behavior, and uses survey data to set speed limits that do not differ radically from the 85th percentile of speeds measured. For Joshua Tree, that standard was measured at 48 mph in the October 2013 survey. And people do drive the 65 mph limit allowed in the approaches to the village. Given observed speeds, there is no way that Caltrans is going to lower the 45 mph limit in town, nor the 65 mph limit outside of town. So the question is: how should the speeds change in a transition zone? According to the Manual, the zones are too short for gradual stepdowns, so abrupt changes with warning signs are the only way to go. If you want to see whether you think Caltrans is properly following its own rules, you can find the Manual at
http://www.dot.ca.gov/hq/traffops/engineering/mutcd/pdf/california-manual-for-setting-speed-limits.pdf
The relevant section is 3.4.1. Zone Lengths
