Most People are Driving: What Opportunities are Available for Reducing Automobile Trips?
As part of this study, project consultant Fehr & Peers purchased anonymized and aggregated GPS data from Streetlight Data. These data were collected for people traveling to, from, and through Walnut Creek between April 2017 and March 2018. The data represent a sample of GPS devices in the region. Commute versus non-commute trips are estimated based on where the GPS device was located during the night and day, the duration of the stay in a particular location, and the underlying land uses at the site. These GPS data provide insight into travel patterns of Walnut Creek residents, workers, and visitors. The key findings from this data analysis are highlighted below.
The majority of work trips start outside of Walnut Creek, with most originating in Concord, Clayton, Martinez, and other areas in East Contra Costa County.
Non-work trips are centered around downtown and Broadway Plaza.
The majority of non-work trips start within Walnut Creek; however, there are significantly more non-work trips from Lafayette, Moraga, Orinda, and Saranap compared with work trips.
Trips through select roadway segments show that a large portion of trips start and/or end outside of Walnut Creek. Roadways closer to the downtown core have the highest percentage of trips that stay completely within Walnut Creek.
Travel Flow Analysis
Commute Travel Patterns
Walnut Creek employment commute trips were collected at four key employment centers.
The majority of trips to the following employment centers came from outside Walnut Creek:
Kaiser Medical Center
John Muir Medical Center
In the figure below, the areas on the map that are shaded darker blue indicate a higher proportion of home locations (e.g., origins) for people who work at employment centers in Walnut Creek. The bar chart next to the map shows the proportion of trips destined for each employment center by origin location. For example, over 45 percent of commute trips to the John Muir Medical Center campus originate in Concord/Clayton/Martinez, whereas just over 10 percent originate in Walnut Creek.
For all employment centers, the greatest proportion of commute trips originate in the Concord-Clayton-Martinez region, with over 30 percent of commute trips starting there. Approximately 10 – 20 percent of commute travel originates from within Walnut Creek. A large portion of commute travel also originates in Eastern Contra Costa County and in the Alamo/Danville/Tri-Valley region.
These travel patterns show that the majority of people employed in Walnut Creek live in Central and Eastern Contra Costa County. While a significant proportion of the Bay Area population lives to the west of the Oakland Hills, this population comprises only a small proportion of travel to Walnut Creek for work.
Non-Commute Travel Patterns
Non-commute travel patterns to destinations in Walnut Creek are different than those for commute trips. In the figure below, the areas on the map that are shaded darker blue indicate a higher proportion of trip origins for non-commute trips with destinations in Walnut Creek. The bar chart shows the percentage of non-commute trips from each origin location.
Unlike commute trips, most non-commute trips originate within Walnut Creek, with approximately 50 percent of trips starting in Walnut Creek. Lafayette, Moraga, Orinda, and Saranap also make up a much larger proportion of origins for non-commute trips. Concord/Clayton/Martinez origins also comprise a significant proportion of non-commute travel into Walnut Creek.
The downtown area is a key destination for non-commute travel into Walnut Creek during the week and on weekends, as shown on the figure below. The downtown area is divided into a number of geographic subareas, and the colors of the different subareas on the map correspond to the bar chart adjacent to the map. The percentage of trips with a non-commute destination in each geographic zone is weighted by area so that zones of different sizes may be compared to one another.
As one might expect, Broadway Plaza and the downtown areas adjacent to it (the area bounded by South California Boulevard, Newell Avenue, North/South Broadway, and Civic Drive) are popular destinations for non-commute trips due to the high concentration of retail outlets, restaurants, and entertainment venues. A large proportion of travel also occurs along the Main Street Corridor and North Downtown Walnut Creek. Auto dealerships, auto repair shops, retailers such as Target, and services such as banks and medical offices are located in these areas.
Travel Through Key Corridors
Fehr & Peers also collected GPS data through Streetlight Data for 12 roadway segments throughout Walnut Creek. The data identify where people started and ended their trip if they passed through these particular locations during the week (Monday through Friday). The figure below maps these 12 locations and shows the breakdown of travel patterns for each.
For all 12 roadway locations, the majority of trips passing through these locations start or end outside of Walnut Creek or are passing through Walnut Creek. Locations near “gateways” adjacent to I-680 or on regional roadways in the eastern part of the city have very few if any internal trips with both origins and destinations within Walnut Creek. Locations near the center of downtown or just east of downtown along Ygnacio Valley Road have much higher shares of internal trips.
This data highlights that downtown is a key area for travel taking place in Walnut Creek.
Walnut Creek is employment heavy.
Walnut Creek has more people commuting in than commuting out. Therefore, transportation demand management (TDM) measures targeting work trips may be more effective than those targeting residents.
Non-commute trips are primarily from Walnut Creek.
Unlike commute travel, the majority of non-commute travel is local. There is an opportunity for the City of Walnut Creek to focus on shifting these shorter, internal trips to other modes of travel.
Commute trips are primarily from east of the Oakland Hills.
While there is high population density and good transit service west of the Oakland Hills, the majority of commute travel comes from areas east of Walnut Creek. BART serves some of these areas; however, existing transit access for many Walnut Creek employees may be limited.
Travel internal to Walnut Creek is centered around downtown.
The majority of travel on key corridors in Walnut Creek has a start or end outside of the city, but downtown has a larger proportion of internal travel. Therefore, improving accessibility for non-auto modes in the Core Area has the most potential to shift how people travel.
Needs, Opportunities, and Challenges
The need to manage and reduce vehicle trips will only increase. Walnut Creek is an employment, retail, and entertainment hub for Central Contra Costa County. While this has helped create a thriving economy, it has also led to a high level of automobile travel into and out of Walnut Creek. Existing infrastructure and development patterns oriented around automobile travel have also contributed to the high volume of automobile trips into, out of, and within the city.
The City’s investment in and support for public transit combined with its adoption of policies aimed at managing automobile trips and parking has helped to manage the growth in vehicle trips. However, as the number of people living in, working in, and/or visiting Walnut Creek grows, the City will need to implement additional strategies to manage and reduce automobile traffic.
Walnut Creek can implement programs and prioritize infrastructure improvements that will reduce vehicle trips. Because Walnut Creek is already a well-established regional center, more aggressive TDM measures can be implemented by the City and employers without greatly deterring travel. Furthermore, Walnut Creek’s easy access to two BART stations provides alternatives for regional access to housing, jobs, shopping, entertainment, and services. Walnut Creek can focus TDM measures around these regional facilities, including major employment locations, to catalyze their benefits to the community.
While much of the automobile travel on Walnut Creek roadways has a regional origin or destination outside of Walnut Creek, a greater emphasis on employer TDM programs could help reduce commute-related automobile trips originating in both Walnut Creek and other parts of Contra Costa County. Additionally, improving bicycle, pedestrian, and public transit infrastructure and services within the city can facilitate non-auto access to BART stations and shift internal trips currently made by automobile to more sustainable modes of transportation.
The West Downtown and North Downtown Specific Plans also present an opportunity to use future land use changes and infrastructure investments to build on Walnut Creek’s existing investments in public transit and bicycle and pedestrian improvements. Both of these plans focus on creating a greater density and diversity of land uses and recommend transportation policies and improvements designed to facilitate and encourage travel by public transit and active transportation modes.
Traffic in Walnut Creek is a regional and local issue. Many more workers commute into Walnut Creek than commute out, and the great majority of them drive. While a greater proportion of Walnut Creek residents make non-commute trips within the city, those who live outside Walnut Creek also drive to the city for shopping, dining, entertainment, and services. These regional automobile trips will be more difficult to shift to other modes due to the fact that existing infrastructure and development patterns are oriented around automobile travel, and relatively few viable alternatives to driving exist. Changing these conditions will require regional coordination between multiple jurisdictions and agencies in East Contra Costa County.