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Pros & Cons - 4 to 3 Lane Change

Before and After Lane Config

This webpage pertains to the Alameda de las Pulgas lane change from 4 lanes to a 3 lane configuration. It is an on-going evolution being shaped by community input and concerns.


  • Significantly shorter crosswalks (about 25% to 30% shorter, 60% shorter at "Y" intersection)
  • Significantly safer roadway for all pedestrians, cyclists, motorists, and residents
  • Much calmer traffic with fewer distracted drivers 
  • Center left turn/merge lane - eliminates many of the current sudden stops and swerving, caused by turning motorists stopping in the travel lane
  • Turning left on to Alameda from side streets and driveways  -- much easier as only 1 calmer travel lane to coordinate and ability to use the center merge lane as a refuge to merge into travel lane . Currently one has to coordinate the two on coming lanes plus the lanes that one is turning on to -- with no safety merge lane refuge
  • Greatly improved cycling safety with the buffered dedicated bike lanes and removal of the 'shared' bike traffic lane (aka no need for Sharrows)
  • Allocates the room needed for the future wider and ADA compliant sidewalks.
  • Emergency response route is improved by having only one lane each direction, with room for motorists to pull over and ability for emergency vehicles to use the full roadway of 40+ feet
  • Retains parking
  • Protects several significant/heritage trees that are near current walking path
  • Safer and easier for Residents to enter/exit driveways
  • Does not restrict volume of traffic - same amount of traffic flows, just calmer and lower speed


  • Peak hour traffic on one lane can have a longer line than the current two lanes
  • While the expense of this is low ($30k to $40k), it is still an expense
  • This forces community to decide between safety and higher speed traffic (especially at peak hour)

Comment count



Remember when this was done to the Avy/Alameda area around the Goose? Supposedly we were to have "Carmel-like experience", by slowing/calming traffic... well, we sure did SLOW the traffic... ugh! And the woman responsible for spearheading the idea promptly relocated when the project was completed! Thanks so much. Now we suffer daily, not exactly a calming experience. Do you really want to share this with more of MP and Atherton? Atherton will be needing more lanes, not less, when the Las Lomitas School project is completed.
BTW, I cycle 5 miles to and from work 3X a week, and I navigate with care thru the areas mentioned to Portola Valley using Alpine Rd.

This 4 to 3 lane change does not include sidewalks, but does include the survey boundry for the future sidewalks (see Safety Issue #11 - Alameda Sidewalks).  Since the proposal is not to encroach on residential property for the new and wider sidewalks, it will instead use the available road width for the needed sidewalk width.    The primary action needed for this proposal is re-striping the traffic lines:  Removing current lane marks and painting new 3 lane configuration lines.   That restriping process will also provide the survey marks for future ADA compliant sidewalks.