Traffic Dashboards

The historical and publicly available data on the traffic volume of California highways can be found on the Caltrans website; 

https://dot.ca.gov/programs/traffic-operations/census.

The traffic data is formatted as a separate Excel file for the years 2013-2021.  The most recent dataset for 2022 is provided as a shapefile that includes latitude and longitude for each measurement location. The data includes one column for each location in which traffic was recorded.  The columns for each observation included location description variables such as county, route, post mile, and district.  Each observation includes quantitative measures such as annual average daily traffic (AADT) in vehicles per day, peak month AADT, and peak hour AADT.  Each of these three measurements had an additional 2 attributes measuring incoming and outgoing traffic for a selected location. 

For collection, very few locations are counted continuously.  Traffic counting is mostly generated by electronic counting instruments moved throughout the state.  The resulting counts are adjusted to an estimate of annual average daily traffic by compensating for seasonal influence, weekly variation, and other variables.   This data is used in a variety of applications, from evaluating traffic trends to planning highway development. 

Many steps were taken to clean and organize the data before it could be analyzed.  Rows with missing values and unwanted variables were removed.  Data types and formats were standardized for each year with the addition of a year column, and all data was merged into a single CSV file.  While the descriptions of each measurement location were not consistent from year to year, the data was missing values of latitude, and longitude was merged with the data from the shapefile.  This gave the majority of the points a geographic location.  The locations that did not have a measurement for each year were removed, and over 60,000 rows of data remained. 

The two dashboards below were created using Tableau. 

The trends in traffic volume for California can be seen above.  The aggregation of all points showed a gradual rise in traffic from 2012-2019, with a sharp decline in 2020 due to the COVID-19 pandemic.  Traffic rose in 2021 and then fell to near COVID levels again in 2022. 

This dashboard shows the total measurement locations within each county, as well as the average peak hour (or traffic during rush hour) for each highway with the ability to filter by county.  

The second dashboard displays the average AADT by county, with the ability to filter by year.  It also includes a map that plots each measurement location as a dot, and the size of the dot is represented by the average peak hour, with the ability to filter by year and highway route.