Impact on Rockridge BART station patrons
The BART tracks running through Rockridge are located between the eastbound and westbound lanes of Highway 24 (four lanes in each direction); the Rockridge BART station platform is also located right in the middle of Highway 24. The proposed soundwalls would bracket the Rockridge BART platform on both the north and south sides and would extend east and west of it for thousands of feet. The height of the proposed soundwalls could be as much as fourteen feet, measured from the Highway 24 roadway. (Soundwall height is limited to fourteen feet or 10% of the width of a freeway and Highway 24 is 160 feet wide.) This platform is approximately six feet above the Highway 24 roadway. This would allow a soundwall height of about eight feet above the Rockridge BART plarform. Yet there has been no mention by proponents of the proposed soundwalls of the possible aesthetic and environmental effects that their construction would have on BART patrons at Rockridge.
I raised these concerns with BART. In an e-mail dated October 16, 2012, BART Customer Services Rep Michael J Moran wrote,
"...it seems any potential changes in freeway sound affecting passengers at the platform is presumed to be of little effect as persons awaiting trains generally are there for a brief period of time....average of less than 15 minutes weekdays and less than 20 minutes evenings and weekends. Additionally, the distance of these proposed sound walls from the passenger platform is over 63 feet away - which provides sufficient area for rebounding noise to dissipate as well as the four lanes of flowing traffic to also buffer such sound.
As far as pollution from passing vehicles, it's highly unlikely that the sound walls walls would affect this. Prevailing breezes would carry away any fumes as would the air current created by the flowing vehicular traffic."
However, at the September 27, 2012 public meeting on soundwalls Glenn Kenoshita, a Caltrans engineer who is versed in soundwall construcition, stated that based upon his experience the proposed soundwalls would increase sound levels at the Rockridge BART platform. This appears to contradict BART's statement.
With soundwalls on both sides, "prevailing breezes" that presently dissipates emissions from vehicles operating on Highway 24 would be partially blocked. In fact, since the proposed soundwalls would extend far beyond the Rockridge station on both sides, they might funnel emissions towards the platform.
On November 13, 2012 I made a request to BART under the California Public Records Act. I asked for any documents related to calculations or engineering studies that support Mr. Moran's statements. Kenneth A. Duron, District Secretary for BART, responded on January 31, 2013 and stated that "there are no environmendal studies or documents which are responsive to your request". Mr. Moran also responded as follows:
"I am aware of the comment of Mr. Kenoshita indicating that soundwalls could increase noise though there seems to be no data or asny technical and environmental reports offered as support... [My] comment that such sound would have little effect is based on understanding that passengers are not there for extended duration... My comment regarding the prevailing breezes also is by observation at platform, those breezes flowing parallel to the platform along the greater stretch of open freeway and not perpendicular so I did not view wall placement as relevant. No data is presented to indicate any trappiong of exhause fumes.
In other words, Mr. Moran's statements are completely ad hoc and without any scientific or expert basis. He nevertheless attacks Mr. Kenoshita's statements, which were based on expertise both with the simulation programs used to model noise near freeways and with the results of actually building soundwalls. And as someone who has lived in the second row of houses from from Highway 24 for 39 years, I know that most of the time the prevailing breezes do not blow along the freeway.
One might conclude that BART as a whole does not care if its patrons are subjected to greater levels of noise and air pollution, and issued its statements in an attempt to deflect criticism. However, newly elected District 3 BART Director Rebecca Satltzman, who represents the Rockridge area, has taken an interest in this issue.
There is evidence that BART knows the effects of putting a station platform in the middle of a freeway, since there are two such stations on the Dublin/Pleasanton line. One need only note the differences between the design of the Dublin BART station (built first) and the West Dublin BART station (built after both the Dublin station and the Dublin/Pleasanton line were already in operation). The Dublin station platform is open to the freeway; the center of the West Dublin station platform is protected from the freeway by walls on both sides. (There are no soundwalls around Highway 580 next to the Dublin or West Dublin stations.) It appears that the experience with Dublin influenced the design of the West Dublin station; and that the walls at West Dublin were installed to protect BART patrons.
The configuration of the Rockridge BART station platform is presently the same as that of the Dublin station: it is open to the freeway on both sides. Adding soundwalls on the outside of Highway 24 would trap noise and vehicle pollution in the Rockridge BART platform area. There are no walls to protect the Rockridge platform from the freeway, as there are at the West Dublin station.