Percent change in average vehicle travel time along major City corridors

Status

Average travel times for Austin arterial roadways grew by 0.1% in 2017, 5.4% in 2018 and 3.4% in 2019. The rate of population growth has hovered under 3% in recent years, and the City’s goal is to keep the rate of increase in travel time lower than the population growth rate. Currently, travel times on Austin arterial roadways are growing at a faster rate than the City’s population.

Trending

Travel times are increasing each year as Austin continues to grow. Austin’s population has grown in recent years by approximately 3% each year. This population growth has contributed to increased traffic volumes and travel times. For the past two years, travel times have grown at a greater rate than population trends. Travel times are increasing each year, even if the percent change is not increasing.
Note: To see the underlying data for this chart, please select the "View Source Data" link.

Additional Measure Insights

The Austin Transportation Department (ATD) operates and maintains over 1,000 traffic signals across the city. ATD’s Annual Signal Retiming Program retimes each of these traffic signals on a three-year rotation to keep up with changing traffic conditions and population growth. ATD also uses the latest signal performance analytics to address traffic issues as they arise. These efforts aim to keep corridor travel time from growing as quickly as traffic volume does across the city.

As Austin grows, more trips will need to be made by transit, walking, biking, and other modes to slow the growth of arterial travel times and congestion. ATD is working to promote alternative modes of transportation from vehicular trips by adding bicycle infrastructure, partnering with Capital Metro to improve transit infrastructure and service, and creating more walkable and pedestrian-friendly environments.

Measure Details and Definition

1) Definition:  Anonymous travel time data is provided by a third-party vendor, INRIX. This data measures speed and travel time along Austin streets. Travel time along street segments are measured over the course of each year and averaged along each corridor. The total travel time for all corridors is then compared to the previous year to measure the percent change in travel time for the city.

2) Calculation method: This measure is calculated by summing the average travel time of each roadway segment along each corridor throughout the year. These average weekday corridor travel times (6 a.m. - 8 p.m.) are then summed and compared to the previous year to get the percent change in travel time. The formula is:

(Total Average Travel Time for All Corridors for Current Year - Total Average Travel Time for All Corridors for Previous Year) / Total Average Travel Time for All Corridors for Previous Year

3) Data Collection Process: This data is provided by a third-party vendor, INRIX, which reports speed and travel time data along roadways. This data is recorded from anonymized probe data from smart devices used during travel. This data is recorded from anonymized probe data from smart devices used during travel along corridors as seen in this web map. Calculations were adjusted to remove missing or incomplete data within the INRIX dataset for 2017 for the following corridors: Burleson Road, Metric Boulevard, and South Pleasant Valley Road. 
In 2021, the INRIX segments for which this metric was calculated on was adjusted, resulting in a lower travel time as compared to previous years. In order to maintain historical integrity, previous years’ data was not altered. For this reason, data from 2021 and beyond is significantly different than the previous years.

4) Measure Target Calculation: The annual population growth of the City of Austin has been approximately 3% each year. The City aims to keep average travel times throughout the City growing at a slower rate than population.

5) Frequency Measure is Reported: Annually (Calendar Year)

Date page was last updated: July 2022