SVBC members and staff have been working with the San Mateo County of Public Works in an effort to redesign the Alpine Road underpass at 280. This was precipitated by the recent death of Lauren Ward.
I was invited to attend the monthly meeting of the club that Lauren's husband rides with last night. They are, understandably, motivated to help make the roads safer for cyclists at this time. We discussed some of SVBC's advocacy and I invited them to work with us in our efforts to make the roads safe--starting with the Alpine/280 intersection redesign.
The folks at San Mateo County have given several us drawings of the potential intersection improvements at Alpine/280. For those of you who would like to do a technical analysis, I invite you to download the 4 pdfs and let us know your thoughts by leaving a comment to this post.
Clearly, any of the alternatives would be a huge improvement to the current situation. It's important to note that the colored bike lane option (D-4) would require special permission from the state, meaning a longer timeline for implementation. I rather like the idea, though--it really helps motorists understand where bikes are likely to be positioned. Although I think green is a more widely adopted color.
| Attachment | Size |
|---|---|
 Alpine280_D1_013111.pdf | 24.45 KB |
| Alpine280_D2_013111.pdf | 24.57 KB |
| Alpine280_D3_013111.pdf | 24.04 KB |
| Alpine280_D4_013111.pdf | 24.76 KB |
Comments
jimchoff
February 9, 2011 - 7:05am
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Alpine Rd
Like the colored bike lanes. Even though green is a frequently used color, I have seen them in blue, red, yellow. I like red, myself.
I would like to see additional yield signs in the vicinity of the striping designator "R4-4" on the drawings. One in the striping area and another on the left turn median.
dino777biker
March 2, 2011 - 1:08pm
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Stripping on Alpine Rd where it goes under 280
I concur with the comments on favoring Option 2. This option has bicyclists making fewest crossings of automobile traffic and puts the cyclists in the safest, most visible, and most obvious position on the road.
I think coloring the lane will be a significant safety improvement. It informs both cyclists and motorists on how to move through this section of road.
MikeOnBike
February 9, 2011 - 9:44am
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Based on a discussion of a
Based on a discussion of a different interchange fatality https://www.facebook.com/photo.php?pid=1564642&l=73a9c80bd5&id=1574017310 I assume we'd want to support the design(s) which "make(s) it clear that the motorist is the one who must merge, and that the bicyclist simply has to hold their lane position."
At first look, I'm not sure any of the four designs meets that goal. Some of the designs might be fixed with some minor changes.
rgdurham
February 14, 2011 - 9:06am
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Alpine bike lanes
I would like to see a combination of variation D-2, where vehicular traffic crosses the bike lane (6 foot width) only once getting on to 280 north and once again leaving 280 south and D-4 the colored bike lane.
Traffic should be slowing for the stop sign and the turn onto the freeway. The colored lane emphasizes the correct place for cyclists. For both parties.
This way the striping can be done quickly while approval is sought for the colored lane.
I would like to see a yield sign posted at the freeway exit also.
Eric Nordman
February 27, 2011 - 10:04am
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Advantages of D2 design for Alpine Road
I think D2 provides the safest approach for Alpine Road at 280. In the southbound direction the merging occurs just before the stop sign. Drivers are often slowing or stopped. The other designs have merging occurring under the freeway overpass. At this point drivers often switch to freeway mode and are less likely to merge safely with bicyclists.
Casey H
March 2, 2011 - 12:49pm
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Please consider D2 with Green
Out of all the options, I would like to point out that D2 provides the simplest and shortest "conflict" zone where cyclists and vehicles are potentially mixing it up. The D3 and D4 options extend this potential conflict zone through the first NB onramp and closer to the overpass. I don't believe this is desirable.
The D2 option would be improved by providing green paint at the three most vulnerable areas, i.e. through the intersections/ramp entrances (please avoid the red; green is pretty much the standard now and it is my understanding that this treatment would not need approval from any state board). I would also advocate providing a thin (2-3') buffer striping between the bike lane and the vehicle lanes feeding the SB ramp entrance as opposed to making the entire lane a colored bike lane. The paint tends to be more noticeable if it's stand alone through the conflict zones and will be easier to re-apply and maintain (these things don't last forever, and if it's expensive the state will be more likely to drag their feet).
Lastly, when talking to the County/Caltrains staff, let's not forget the two eastbound conflict zones. If the crews are out there with green paint, send them to the other side.
David Roise
March 3, 2011 - 7:23am
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I would concur with the
I would concur with the others that D2 is clearly the best option, with minor changes. As others have said, there is only one conflict point in D2--prior to where cars merge right onto NB I-280. After that, bikes stay in the pocket lane, and all freeway traffic (both NB and SB) is to the right of them. All through-traffic is to the left of them. This configuration is most similar to WB Sand Hill Road at I-280, which works pretty well. I would tweak the lane markings under the bridge somewhat, to make it clear that car drivers in the right lane at the stop sign should go straight onto the SB I-280 ramp--there really isn't any merging going on at that point.
One of the engineers commented that D3 is best because merging takes place after the stop sign, where traffic is slow. I think this is wrong. Many car drivers will try to race ahead of bikes at this point to beat them to the merge as they approach the SB I-280 ramp. It would be better for the negotiations to take place prior to the stop sign, where bikes are moving relatively fast and have a better chance to move across the lane. A sign prior to this merge indicating "bikes merging" and pavement markings indicating "I-280 only" or "freeway only" would be helpful.
One last point, please be sure that the pocket lane is wide enough, ideally wide enough for bikes riding two abreast. The pocket lane on EB Sand Hill Road at Santa Cruz Ave./Alpine Road (the big intersection that was rebuilt a few years ago) is much too narrow. The pocket lane on WB Sand Hill Road over I-280 is pretty good.
de2r
March 3, 2011 - 9:13am
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I support this position
I support this position entirely. The merging across and adjacent to the bike lane used in D1, D3 & D4 look much more problematic than the single merge bikes must do in D2. I'd rather merge through traffic which is slowing down to a stop, than though traffic accellerating toward the freeway onramp.
A colored bike lane would likely improve D2 further, with less confusion than in the D4 option. In D4 drivers actually have to cross the colored lane to get onto the freeway. This gives them the message that it's OK to drive through the colored bike lane. I think we want cars to feel the colored lane is inviolable space.
MikeOnBike
March 3, 2011 - 11:34am
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"The colored lane is inviolable space"
No, we want motorists to see the bike lane (colored or not) as a space they need to YIELD and MERGE across. See the link I posted on Feb 9. We want to make it clear that the motorist is the one who must merge, and that the bicyclist simply has to hold their lane position.
Paul
March 3, 2011 - 1:58pm
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Prefer Option D2
I prefer option D2 and I am in agreement with most of the comments posted here. Merging before the stop sign and the 280 NB on-ramp is better for a number of reasons:
1. traffic is slowing, and bikes are moving, giving a cyclist better opportunities to merge.
2. merges after the stop sign have lighting issues under the freeway overpass.
3. a stopped motorist should be able to see the bike lane, and any cyclists in it pretty clearly
4. motorists do not have to merge after the stop sign, giving them less incentive to try to speed away from the stop.
I will leave pavement color issues to others. The most important thing is to make the bike lane clearly visible. If this is better accomplished through the use of colored pavement, I am all for it.
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