From Speaker Ryan Whipple from Session 2:

  • Do you foresee any issues with driver comprehension of displaying the circular green indication together with the flashing yellow right turn arrow indication?
    • Excellent question, it’s definitely something we considered.  The flashing yellow left turn arrow with green indication is currently being used at multiple locations throughout the state for permissive lefts, and the initial results from what we’ve researched have had good compliance.  We anticipate that the flashing yellow right arrow will have similar compliance.
  • With all the additional striping in the Palm intersection, along with additional signing and changes to traffic signal phasing, is there concern that you are asking too much from the driver to compute as they travel through the intersection.
    • This is also a great question.  We actually just received last week comments from the City of Imperial Beach about this exact same concern.  After working with our team, we’re actually going to propose removal of  some of the conflict striping for the bicycles crossing 13th along Palm (the adjacent project).  Additionally we’re going to use programmed visibility heads for the bicycle signal heads to minimize visual conflicts for drivers.
  • Do you allow the display of bike head (one direction) and vehicle green ball head at the same time without “no right turn” restriction?
    • Yes. The vehicle green ball head with flashing yellow arrow indication runs with the bike head.  The no right turn on red EMS only occurs during the Leading Pedestrian Indicator (LPI) of both the bicycles and pedestrians.
  • Did you consider a protected intersection treatment at 13th / Palm?
    • Yes, the original conceptual plans assumed a fully protected intersection.  However, during interagency coordination with the City of Imperial Beach, the City expressed that due to the high volumes and speeds on Palm Avenue, that they didn’t want to add pop-outs into Palm.
  • What was the methodology for safety analysis during environmental review of alternative alignments?
    • To clarify – the safety analysis was conducted to determine the type of facility along each roadway.  However the selection between different alignments didn’t include accident history or further safety analysis. Rather LTS scores were used as a proxy for safety  as one of the screening criteria.
    • In terms of using accident data, we looked at SWITRS data to determine where the high incidence of bicycle/vehicle collisions.  At locations with high accident history with existing bicycle facilities – we proposed upgrades to the facility type to better protect cyclists.  At locations with high accident history without existing bicycle facilities – the engineering and traffic team proposed a bicycle facility that was as safe as possible while staying within the curb-to-curb.  (The necessity to stay within the curb-to-curb was based on the need for the project to receive a Categorical Exemption on the Environmental Document in order to still meet the grant deadline).
    • The environmental document itself only used a qualitative assessment of bicycle safety without the project and with the project.  At the time of publication of the environmental document, the final alignment was already selected.
  • Also, what about bicyclists understanding that there is potential for vehicles to be turning (i.e. not protected movement for bikes)?
    • While the programmed visibility heads will only be for the bicycle signals, the flashing yellow arrow indication will be visible to bicycles.  Additionally, they will be able to see the No Right Turn EMS sign go from being lit to turning off.  There will also be a modified R10-15 sign stating that turning vehicles will need to yield to bikes and peds.