How are we doing?
There are many ways to measure traffic congestion - especially because it varies due to traffic incidents, time of day, weather, work zones, special events, traffic control, and bottlenecks. The conditions for traveling between two locations depends on the combination of all of these factors. For this indicator, we track the change in freeway miles driven per capita and annual hours of delay during commute hours.
Traffic congestion received a neutral rating due to unusual traffic conditions due to stay-at-home pandemic restrictions that ended on June 15, 2021. Between 2020 and 2021 total freeway vehicle miles traveled (VMT) in San Diego County increased by 14% and the annual peak hour vehicle delay per commuter increased by 61%. Traffic congestion has a broader societal impact, increasing travel time and fuel costs, and negatively affecting the environment and public health.
Rating: Mixed Results
Unusual traffic conditions due to pandemic Stay-at-Home Order
How much do San Diegans drive?
San Diego freeway VMT per capita per day is about the same as in Orange County, and above the state average. Other Southern California counties, such as Riverside and San Bernardino County, had higher per capita freeway VMT from 2013 to 2018. However, this gap has diminished significantly in recent years from 2019 to 2021. In 2021, the freeway miles per capita statewide were 12% higher than that in 2020. 2020 had the lowest vehicle miles traveled per capita in the past ten years most likely due to the Stay-At-Home Order issued in March 2020 due to COVID-19, that limited all non-essential travel. In 2021, travel resumed but did not reach pre-pandemic levels.
San Diego and Orange County tracked similarly in total VMT over the past ten years, which was much lower than Los Angeles County. Los Angeles County is similar in size (4,751 square miles) to San Diego County (4,500 square miles), but with three times the population. Riverside County, about twice the size of San Diego County (7,303 square miles), and San Bernardino County, three times larger than San Diego County (20,105 square miles), also had similar total VMT as San Diego County, despite the larger land area.
Freeway VMT also varies by day, night, weekdays, and weekends. Weekday peak hours are defined as 6 to 10 am and 3 to 7 pm. The miles traveled during peak hours have consistently made up about 30-35% of total freeway miles over the past ten years, even during the pandemic in 2020 and 2021, while miles traveled during weekday non-peak hours, weekends, and holidays have made up a greater portion of total VM on all roads.
The total weekday, weekend and holiday freeway VMT in 2021 was 15% higher than in 2020. There was an 11% increase in weekday peak hour VMT from 2020 to 2021. Although traffic levels increased in 2021, they did not return to pre-pandemic levels.
Another way to measure traffic congestion is the peak hour delay. The peak hours delay reflects "stop-and-go" severe freeway congestion with vehicle speeds averaging below 35 miles per hour. Tracking the weekday peak hour delay measures how the system is managing the demand of and changes needed to improve the quality of access to work and/or other activities. The freeway delay in the afternoon peak hours is more severe than during the morning peak hours.
San Diego County drivers spent more than 12 million hours on the freeways due to delays in 2019. The hours of delay have more than tripled since 2010. However, the peak hour delay in 2020 and 2021 was 75% and 60% lower than that in 2019, respectively. Combined with the reductions in VMT during peak hours, the traffic flow improved significantly in 2020 and 2021.
U.S.-Mexico border region
And yet another metric to track traffic conditions is to monitor the number of vehicle crossings that occur from the three land-based ports of entry from Mexico into the United States within San Diego County: Otay Mesa, San Ysidro, and Tecate. In 2021, the total number of northbound personal vehicle crossings at all three ports of entry was approximately 19 million, 18% lower than that of the pre-pandemic peak in 2018, most likely due to the pandemic-related travel restrictions with the latest update in July 2021. The San Ysidro port of entry had the highest number of personal vehicle crossings of all ports of entry into the United States in 2021, with almost 14 million crossings, followed by the El Paso port of entry in Texas with 6.3 million crossings, and the Otay Mesa port of entry with 4.7 million crossings.
When monitoring freight truck crossings, there are two land-based ports of entry from Mexico into the United States within San Diego County: Otay Mesa and Tecate. In 2021, the total number of northbound freight truck crossings, not including privately owned pick-up trucks, at both San Diego County ports of entry was approximately 1 million, a slight increase (1%) from 2020. The freight movement did not seem to be affected by the border travel restriction, most likely due to its essential nature. About 93% of the freight truck crossings occurred at the Otay Mesa port of entry. The Otay Mesa port of entry was the second busiest port of entry in 2021 for freight truck crossings along the U.S.-Mexico border following the Laredo port of entry in Texas.
Why is traffic congestion important?
High quality of life means the region boasts a thriving economy and a healthy environment accessible to all in the community.
Economy
Traffic congestion has negative impacts on individuals and the economy. Fuel waste from traffic congestion increases costs to individuals and businesses through increased travel times and lost productivity. On the other hand, a certain amount of traffic congestion can indicate a thriving regional economy. This is particularly visible in the San Diego border region, which oversees the transportation of consumer goods and materials. As a short-term effort to relieve congestion, the Otay Mesa East project added 20 new lanes and separated cargo from passenger traffic in 2017. In October 2022, Governor Newsom announced an agreement with Mexico for a new Toll Revenue Sharing system for four toll lanes, which will help improve the infrastructure at this entry point, reducing wait time, congestion, and emissions. To reduce future commercial truck congestion, the San Diego Regional Chamber of Commerce advocates for the re-establishment of a functional cross-border rail system, which would also significantly improve multimodality.
Environment
Traffic congestion impacts the environment negatively by decreasing air quality, increasing the use and waste of fuel, increasing costs to both individuals and businesses, and increasing greenhouse gas emissions affecting the climate in the long-term.
Equity
Although San Diego does not rank among the top 10 urban areas in the U.S. for traffic congestion, congested roads decrease air quality, especially in communities in the immediate vicinity. Many of these highly exposed communities also have higher rates of poverty and therefore are more vulnerable to the impacts of air pollution.
Regional Response
Policies
The Calexico Port of Entry is undergoing an expansion to ease traffic congestion at the port. Upon its projected completion in 2023, the expansion will add six northbound vehicle lanes and five new southbound lanes.
Projects
The County of San Diego’s Active Transportation Plan (ATP) was approved by the Board of Supervisors in 2018. The ATP aims to increase bike lanes and walking trails and improve safety for non-motorized vehicle users to improve public health and enhance regional efforts to meet greenhouse gas emission goals. The City of Encinitas also updated its ATP in 2018 and received a grant to work on the implementation of the ATP with a list of prioritized projects, which will be available in early 2023. A statewide Progress Report of ATPs will be completed by Caltrans in March 2023.
Partnerships
Circulate San Diego, in partnership with Rady Children’s Hospital and the California Office of Traffic Safety, launched online educational resources and activities to promote safe walking trails and biking lanes.
What are we tracking?
We track annual change in freeway miles driven per capita and total freeway miles driven in select counties since 2012. For the impact of traffic congestion during rush hour, we calculated the annual hours of delay during the morning (6 to 10 a.m.) and afternoon (3 to 7 p.m.) commuter hours since 2006. We also track northbound personal and freight vehicle border crossings into the U.S through the San Ysidro, Otay Mesa and Tecate ports of entry.