The Teen Safety Heat Map offers many different options to visualize and analyze teen collision data in California. To use this tool, click on Teen Safety Heat Map from the Tools dropdown menu. This user guide provides instructions on how to use the tool's many different functions.

1. Filters

The core functionality of the Teen Safety Heat Map is the ability to compare factors such as collisions, OTS funded teen programs, and demographics to other factors and visualize these comparisons in each county. These filters are located in a collapsible panel towards the right side of the map.

Variable Categories

There are 3 types of variables to choose from - 1) collision variables, 2) OTS funded teen programs, and 3) population and area. Each category is separated into its own yellow box.

Collision Variables

OTS Teen Funded Programs

Population and Area Variables

Variable Explanations

Some common variables explained:

  • Collisions: Driver Age 16-21: Number of collisions involving teen drivers between the ages of 16 and 21.
  • HBD Driver Age < 21: Number of victims killed and injured in which the driver is under 21 and has been drinking (HBD).
  • Driver Ed. Classes: Number of driver education classes.
  • Driver Ed. Students: Number of students attened to driver education classes.
  • Population (100k): Units of 100,000 people (e.g. Alameda had a population of 16.20 in 2015, or 1,620,000).
  • Area (100 sq mi): Units of 100 square miles (e.g. Alameda had an area of 7.47 in 2015, or 747 square miles).

Choosing Filters

To select one, drag it to the green box below that says Drag and drop a variable. The first variable selected is called the Heatmap Variable.

You can select a second factor by dragging it to the green box that says In proportion to (Optional). This is called the Divisor Variable.

For example, the picture to the right shows two factors chosen - OTS Funded Teen Programming and Population (100k). Selecting two factors means the filter will be the ratio between the first and second variables. In this case, it is the ratio of OTS funded programs to the population (100k), or number of OTS funded teen programs per 100,000 people.

Selecting Years

Once a factor(s) has been chosen, sliders will appear that allow users to select which years they want to see the data for.

Note: For some variables, certain years may not be available for query. Unavailable years will have gray lines. In the example above, 2006-2012 is grayed out for the heatmap variable and 2006-2010/2016-2017 for the divisor variable.

Once the ratio and year ranges have been selected, click Show Result to view the query results on the map. Then, you will be able to click Data Summary to the right to view a table of statistics.

2. Results

How the Search Works

If only one variable is selected (e.g. Collisions: Driver Age 16-21), collisions will be filtered based on that factor. Counties and zip codes with higher incidences of that variable will be displayed with darker shades of red. However, if two factors are selected (e.g. Collisions: Driver Age 16-21 and Population-100k), collisions will be filtered based on those two variables AND counties/zip codes will be color-coded according to the average ratio of the first variable to the second (see Legend subsection below).


If the year ranges of the two variables are the same, the counties and zip codes will be color-coded according to the average yearly ratio. For example, if the years 2013-2015 have been selected for both factors, then the average rate is

where a is the first variable and b is the second.

However, if the year ranges are different, the rate will be the total of variable a divided by the total of variable b as below.

Data Summary

As mentioned at the end of the Filters section, selecting Data Summary in the bottom of the filters panel opens a table that displays the ratios for each county for the selected years. For example, the table below shows that in 2013, Alameda County had 5 teen programs and a population of 1,576,000 people, and its average number of teen funded programs per 100k people from 2013 to 2015 was 0.35.


To view a certain category in ascending or descending order, click on the corresponding cell in the table header. For example, to see the counties with the most teen programs in 2013, click # of total teen programming in the 2013 section once.


You can download the data summary as a csv, text or Microsoft Excel file by clicking the export button towards the top left of the table.

3. Map

After the query, a map of California will be displayed with counties color-coded according to the legend (shown below).


The map legend is located towards the bottom left of the map. Counties with higher ratios of the selected factors will be displayed with darker shades of red while those with smaller ratios will have lighter shades.

Infinity Label

In some cases, a label in the legend may be infinity. This is because the second selected factor has 0 occurences in one or more counties/zip codes, which means the ratio is essentially infinity. In the example below, the second factor is number of drivers education classes. Some counties/zip codes, however, may not have these classes. As a result, the number of collisions (first factor) is divided by 0, and thus the ratio is infinity.

County Summary

Clicking on a county will open a popup that displays two graphs. The top one is a line graph with one or two lines (depending on how many factors the user selected). The bottom graph displays the ratios of the selected factors each year. See the Graphs subsection below for more information.


In the example below, the black line in the left graph shows the number of teen programs from 2013-2015 (the selected years) in San Luis Obispo, and the blue line shows the population during those years. The orange line in the right graph shows the number of teen programs per 100k people from 2013-2015.

Top Graph

Bottom Graph

Note: The Yearly Rate graph will only appear when two factors have been chosen (a ratio doesn't exist if there is only one filter) and the year ranges for the two variables are the same.

Show Program List

When a factor related to programs or classes is chosen, users are able to view the programs and related information about them in each county by selecting Show Program List in the bottom right of the county popup. Once again, each category can be ordered by selecting the corresponding cell in the table header (see the Ordering subsection in Data Summary for more info), and the data can be download as a csv, text, or Microsoft Excel file.

Two Program Variables

When two variables pertaining to OTS funded teen programs are selected, the county summary will have two tables, one for each program. In the example below, Driver Ed. Classes was selected as the first variable and OTS Funded Teen Programming as the second. The top table displays information about all the driver's education classes (first variable) in Los Angeles County while the bottom table displays information about all OTS teen funded programs in the area. Both tables will appear in the downloaded file.

Zoom to ZIP Level

Clicking on Zoom to ZIP Level in the bottom left of the county summary will zoom in to that county and display all the zip code areas.

Clicking on a zip code area will open a popup that displays a summary for that zip code, similar to that of the county summary.

Two Program Variables (Zip Code Level)

Just like the county program list, there will be one table for each program in the zip code program list if two variables related to OTS teen funded programs are selected.