August 20, 2024
Newly released Congestion data from INRIX shows that from 2011 to 2023, there was a 4.3% decline in freeway reliability in the region. This means more unpredicted delays. Explore the congestion data in this #TrackingTuesday.
It's hard to plan a trip when you have no idea how long it will take. Travelers want reliable travel times from one day to the next. The same peak hours generally occur every weekday, but on any given day, unusual circumstances like crashes, weather, construction activity, or special events can dramatically change the performance of the roadway. This is referred to as nonrecurring congestion. Data collected by the Federal Highway Administration indicates that nonrecurring congestion actually accounts for more hours of delay than the everyday (recurring) congestion that results from road capacity constraints and heavy volumes. A reliable network may still have congestion in peak periods, but such congestion will be easier to predict—ensuring the region's residents and goods get to where they are expected to be when they are expected to be there.
Connections 2050, DVRPC’s regional Long-Range Plan, aims to ensure the region has a safe and efficient transportation network. Decreasing congestion helps enhance goods movement, increase access to jobs for the region’s residents, increase mobility and reliability, improve air quality, and potentially reduce vehicle miles traveled and related greenhouse gas emissions.
DVRPC’s Congestion Management Process (CMP) uses a variety of traffic data to identify the most congested roadways in the Greater Philadelphia region. It uses this information along with other analyses to recommend multimodal strategies that improve the flow and people and goods, enhance safety, and expand travel options on the region’s transportation network.
This Tracking Progress update aligns the congestion indicator with the Federal Highway Administration’s Transportation Performance Management (TPM) metrics. These metrics include travel time reliability on the National Highway System (NHS), truck travel time reliability on the Interstate System, and annual hours of peak-hour excessive delay (PHED) per capita on the NHS in the region’s urbanized areas. If a segment of roadway is considered reliable, motorists can reasonably expect to estimate how long it would take to drive that segment of roadway on a consistent basis. Truck travel time reliability measures how consistent travel times are on interstates. Annual hours of PHED per capita is the excessive traffic delay experienced by travelers throughout an entire year on roadways, specifically during the weekday peak hours. The “excessive” part of the PHED name is because some level of congestion is recognized as acceptable, and is thus not counted in the measure. Peak travel hours are defined as weekdays 6–10 a.m. and 3–7 p.m. The total excessive delay metric is weighted by vehicle volumes and occupancy. The “per capita” implies that the total delay is shared by all residents; and everyone can benefit when some trips are avoided, shifted to walking or biking, or occur outside the peak time period. Annual hours of PHED per capita is indicated by the ratio of the annual hours of PHED to the population of the UZA.
Levels of congestion in the region have nearly returned to pre-pandemic levels.
- There was a minor increase in the region’s highway Planning Time Index (PTI) values from 2011 (1.36) to 2023 (1.42), indicating 4.3% less highway reliability based on PTI. On local roads, PTI slightly increased to 1.26 in 2023, from 1.25 in 2022, but remained below their 2015 peak of 1.39.
- In 2023, the Philadelphia, PA-NJ-DE-MD Urbanized Area had 13.9 annual hours of PHED per capita, up from 12.5 in 2022. The Trenton, NJ Urban Area had a new peak with 4.4 annual hours of PHED per capita.
- In 2023, 81.0% of the region’s interstate roadways had reliable travel conditions. This performance was better than pre-pandemic, when only 73.3% to 75.0% of the region had reliable interstate travel conditions, but below the 2020 reliability peak of 90.5%.
- The region’s Truck Travel Time Reliability Index was 1.67 in 2023. This value is below the worst performing year, 2018, which had a value of 1.91, and above the best performing year, 2020, which had a value of 1.55—though this occurred during the pandemic when non-essential workers were directed to work from home.
For more details on the levels of reliability on the region’s roadways and other congestion metrics, go to the “How are we doing?” tab in the Congestion Indicator.
Want to download the data for your own use? Under each chart, find a link to the data in DVRPC’s Data Catalog. You can also explore other indicators in Tracking Progress, DVRPC’s interactive dashboard for exploring Greater Philadelphia’s progress toward the Connections 2050 regional Vision.