Stanford Research Park GIS Commute Shed Study

"Because of the upcoming 101 Corridor Study, Caltrain Baby Bullet service, Stanford GUP trip reductions, and ongoing VTA/SamTrans bus route planning, Palo Alto needed more accurate and more current commute data than other cities and transit agencies. We've accomplished this for a fraction of the cost it would have taken using a traditional transportation consulting firm. Compared to recent regional transportation studies our data is twenty times more precise and our participation rates are much higher" - Joe Kott, City of Palo Alto Chief Transportation Officer.

• City of Palo Alto press release. August 23, 2002.
• Gorgeous SRP commute shed map.
• Additional Findings & Commentary
• 1/5 Mile Grid Explained
• Details on the study methodology.
• Palo Alto Planning Commission presentation: PowerPoint. (360kb) 3/03.
• Credits
• Transportation Research Board (peer-reviewed) national conference paper, 1/03: Privacy-Protecting Commute Shed Study. CommuteShed_TRB_111502.doc. "A new methodology has been developed for collecting fine-grained employee commute origination data from employers in major employment centers. Many U.S. multinational firms have adopted the European Parliament Privacy Directive 95/46/EC, the strictest privacy law to date. The methodology discussed complies with this Directive. "Fine-grained" is defined as providing sufficient resolution (approximately 1,000 feet) to assist transportation planning of individual bus stops. Directive 95/46/EC provides for "anonymization" of data to where the data subject is no longer identifiable. Individual address data is aggregated to a 1/5 by 1/5 mile grid at the employer site using commercial geographic information systems software. Once the grid data is taken from employer premises, data is combined with those of other employers, providing further anonymization. 8,200 out of approximately 20,000 worker addresses have been collected from the Stanford Research Park employment center using this methodology. While the sprawling spatial distribution of these addresses challenges many Transportation Demand Reduction strategies, planned transit system improvements should result in a significant patronage increase."

Additional Findings & Commentary

The City of Palo Alto endorsed and assisted the SRP Commute Shed Study to improve transportation planning within SRP - assisting transit agencies, ridesharing agencies, and the City itself. The study built upon the Fall '99 VTA "zip code" Commute Service Study, mapping home originations to a much finer scale. The scale was chosen to be sufficiently coarse to protect employee privacy, but fine enough for micro analysis (answering "how many people are within 1,500 feet of a bus stop?", for instance).

The study reveals a strong likelihood for increased transit use and carpooling. 47% of SRP employees live within a 2 mile radius (2 miles is a popular measure of "bikeable" distance) of a "soon to be Baby Bullet" Caltrain station. Improved bus shuttle service (including Deer Creek Shuttle and employer shuttles managed by CommuteSmart), car sharing, and bike lockers ease the trip from Caltrain's California Avenue station to SRP offices.

In addition, 28% of these workers live within a five-mile radius and 49% live within a ten-mile radius of SRP. New VTA and SamTrans "bus preference service" along El Camino dramatically reduces the speed gap for bus versus auto for these short commutes.

The ever-expanding network of South and East Bay HOV lanes has made carpooling the fastest commute method in these areas. A carpool coming to Palo Alto from North of San Leandro via Dumbarton saves about 47 minutes versus a SOV. The Dumbarton and San Mateo Bridge HOV lanes alone save 19 and 10 minutes respectively. (See Caltrans 2001 Bay Area HOV Report: http://www.dot.ca.gov/dist4/d4hwops/01HOVReport/01HOV_intro.htm.)

1/5 MILE GRID:

Bay area employee home addresses are aggregated into a "25 squares per square mile" grid, with each square measuring 1056 feet by 1056 feet. A square mile in Palo Alto with 1/5 mile grid is shown below:

Each square contains roughly 4 residential blocks, consisting of approximately 144 houses.

Credits:

Thanks to City of Palo Alto (Joe Kott, Chief Transportation Officer; Amanda Jones, Transportation Systems Management Coordinator; and Dave Matson, Geographic Information Systems Manager), Greeninfo Network (Lynn Frederico, Brian Cohen), VTA (Chris Augenstein), MTC (Mike Skowroneck), Anthony-Maymudes Foundation, and Pinnacle Systems.