Presentation to CBAC

April 6, 2017

The April 2017 Caltrans Draft Project Report to install rumble strips in Amador and Alpine Counties has not considered the CBAC recommendations in the Dec. 14 letter to the Caltrans Director. I’d be surprised if the authors of the Project Report have read those recommendations.

I understand that Caltrans has yet to adopt any of the rumble strip recommendations. However, these were approved unanimously by the CBAC in December 2016, and the threat that rumble strips pose to bicycle safety makes a compelling case that they should be considered.

If the recommendations are adopted, the way Caltrans installs rumble strips would change substantially. While the proposed recommendations are under consideration there should be a moratorium on rumble strip installation by Caltrans in California.

This makes economic sense. From the Federal Highway Administration web site the cost of installing rumble strips in the US ranges from $500 to $6000 / mile. The only cited example from the Highway Administration web site of the cost of rumble strip removal was $13,000 / mile in Michigan. So, if Caltrans ends up having to remove rumble strips because of incorrect installation it is likely to cost at least twice as much as the original installation based on Highway Administration information.

Also, before any other rumble strip projects begin Caltrans should fix their recent installation on Niles Canyon Road. Though Caltrans got many aspects of that installation right, rumble strip depth in several places were severely out of specification. We measured a depth in one instance of 7/8 of an inch, almost 3 times the specified depth of 5/16. Caltrans should know its actual cost of removing and replacing rumble strips before it embarks on projects that may need to be corrected.

Here is a list of the specific problems with the Draft Project Report vis-a-vis the CBAC recommendations:

1. The report proposes the use of ground in rumble strips. The main, and most important, recommendation from CBAC is to use an Audible Traffic Striping product approved by Caltrans in lieu of ground in rumble strips. We are aware that Audible Striping is problematic where snow removal is required. But, of the 4 roads covered in the proposed project, only Hwy 88 east of Pine Grove or maybe Pioneer would be affected by snow removal.

2. On page 12 of the project report, section 7A reads: “At the sections of the highway where shoulder width is less than one foot, edge line rumble stripes will be installed as per recommendation from D10 Traffic Safety. Where adequate shoulder width is not available, bicyclists ride on the travel lane.” I am stunned by the level of insensitivity to the plight posed to cyclists by section 7A of the report. Of course, bicyclists are obliged to ride in the travel lane if the shoulder is too narrow. But to advocate putting a rumble strip on the edge line in such a circumstance effectively denies bicyclists access to the paved shoulder, even if it is only one foot wide. Many times when touring I have had to ride my bike onto the gravel shoulder to, for example, get out of the way of two commercial trucks approaching each other. It is unreasonable and dangerous to require a bicyclist in the travel lane to negotiate a rumble strip on his right in order to reach the edge of the pavement. In Standard Plan A40B Caltrans states that: “rumble strips should not be used right of direction of travel unless a minimum of 5 feet 0 inches of clear shoulder width for bicycle use is available between the rumble strip and the outer edge of the shoulder.” The CBAC recommendation concurs with Standard Plan A40B. Section 7A of the project report contradicts both. 3. The first sentence of the introduction mentions “shoulder rumble strips” as something distinct from “edge line rumble strips”. CBAC recommends that rumble strips should always be installed on the edge line. If the CBAC recommendation is adopted the concept of “shoulder rumble strips” would no longer exist for Caltrans. The CHP often cites excessive speed as a contributing factor for highway collisions. A number of studies have shown that drivers reduce their speed when the lane narrows. Installing rumble strips to the right of the edge line effectively makes the travel lane wider. Driver fatigue is also a factor in many of the collisions rumble strips are designed to prevent. It is better to alert a drifting driver sooner rather than later. So, putting rumble strips to the right of the edge line makes no sense from a vehicle safety perspective. Also, bicyclists should not have the space available for them arbitrarily restricted. 4. The photo on the first page of the report shows a 12 inch wide “shoulder rumble strip”. The CBAC recommendations state that all rumble strips should be 6 inches wide. A 12 inch wide rumble strip has no practical advantage over one 6 inches wide. 5. There was no mention in the report of not installing rumble strips on down-grades greater than 5% as was recommended by CBAC.