Partial Underpass Proposal

A Partial Underpass for Churchill at Alma

There has been much discussion about how to achieve grade separation at the Caltrain crossing at Churchill Avenue in Palo Alto. The city has presented a number of alternatives in past years, but all have met with significant resistance. This proposal is an attempt to address the concerns of residents, meeting the requirements of Caltrain, and creating benefits for the city.

The goal of this proposal is to preserve as much of the access provided by the Churchill/Alma intersection as possible.

Design Objectives for the Partial Underpass

Analysis of previous alternatives and their drawbacks led to the following objectives for the Churchill Avenue crossing:

  • Separate Caltrain tracks from Churchill Avenue
  • Separate bikes and pedestrians from traffic and the tracks
  • Require no private properties
  • Allow vehicular access from El Camino to Alma from Churchill Avenue
  • Avoid moving the Caltrain tracks

Design Features of This Proposal

  • Separates bikes and pedestrians from traffic on Alma, Churchill, and the Caltrain
  • Separates Caltrain from Churchill Avenue
  • Requires no private property
  • Provides a bridge over Churchill for the bike trail next to Palo Alto High School
  • Partially closes Churchill Avenue, but preserves access to Alma – and therefore downtown and south Palo Alto – for Southgate and other residents west of Alma
  • Maintains the main traffic flows at the intersection, especially between El Camino and Alma
  • Prevents use of Churchill as a shortcut to Embarcadero, thereby reducing traffic on Churchill in Old Palo Alto
  • Keeps Caltrain at grade level – i.e., no raising or lowering of tracks
  • All infrastructure is at or below grade level, so it doesn't create an eyesore like that of a viaduct

Bike and Pedestrian Safety

The Partial Underpass design provides a separate tunnel under both Alma and the Caltrain tracks. It will originate on Kellogg Ave, just one block north of Churchill and connect to the existing bike trail next to Palo Alto High School. It will provide a safe route to the High School that is only slightly more indirect than the current route at Churchill. The diagram below shows the new bike and pedestrian routes.

Bike & Pedestrian Routes
Public Domain/Michael Price

Impact on Traffic

Based on the analysis by the City's traffic consultant, the Partial Underpass does a better job of handling expected traffic than any other alternative at Churchill. It takes pressure off the Alma/Embarcadero and El Camino/Embarcadero intersections without creating large queues on Churchill or Alma.

Permitted turns and paths through the intersection are shown below. All other current turns are forbidden.

Permitted Turns
Public Domain/Michael Price

Here is some traffic data for many Palo Alto intersections compiled by the City's traffic consultant:

Palo Alto Traffic Study Data

Emergency Response

Emergency response times should not be affected by the Partial Underpass since it preserves nearly all uses of the intersection. The specific question has not been asked, however. Impacts on response time of closing Churchill can be found on the Southgate Closure Impacts page.

Feasibility

After an initial assessment by AECOMAECOM is the engineering consulting firm hired by the City of Palo Alto to design and evaluate each grade crossing alternative., the City's engineering consultants, there appear to be no technical reasons why the Partial Underpass cannot be built. Existing utilities (sewer, water, and gas) can be accommodated in the construction. There is a small increased encroachment on the Caltrain right of way that they will need to approve. There is also a reconfiguration of the sidewalk and bike path along Churchill which will encroach slightly into Palo Alto High School's property which will need approval.

Analysis of the proposal is still being conducted by AECOMAECOM is the engineering consulting firm hired by the City of Palo Alto to design and evaluate each grade crossing alternative. and the City.

Construction Disruption

The construction of the Partial Underpass will inevitably cause some disruption of traffic on Alma and Churchill. The bike/pedestrian tunnel would be built first, so access can occur during construction. The rail bridge over Churchill can be constructed without building a shooflyA shoofly is a temporary detour around a construction zone or other blockage on the mainline tracks.: there are several examples of this being done on other rail lines. Alma will be restricted to one lane in each direction and Churchill will be closed for most of the construction period.

There are several techniques that allow construction of underpasses for rail lines with minimal cost and disruption. Some examples:

Art Engineering, Inc.
Long Island Railroad
Santa Clara Pedestrian Tunnel

Views of the Partial Underpass