Caltrans Transportation Equity Index (EQI) Story Map

All EQI screening scenarios include demographic indicators of household low-income status and Tribal Land status. If either of the low-income household or Tribal Land criteria are met, the block is screened for inclusion for further analysis with the transportation-specific indicators (traffic exposure and access to destinations indicators).

Thresholds:

• Median Household Income: < HCD-defined low-income cutoff OR < 80% statewide median income, OR
• Block intersects or is fully contained within a Tribal Land

To determine a block’s status as either ‘low-income’ or ‘not low-income,’ two measures were used in alignment with  AB 1550 . A Census block group was designated as a ‘low-income’ community if either 1) its median household income was at or below 80% of the statewide median household income, OR 2) its median household income was at or below the 2021 county low-income limits established by the California Department of Housing and Community Development. If either criterion was met, the block group was identified as a low-income community and screened for inclusion for the Demographic Overlay. Block group income data was joined to Census block data using the GEOID20 ID in both datasets. It is important to note that US Census household income data is not available at the block level, so block group-level data was used. For the purposes of EQI, a block is assumed to have the median household income of its parent block group.

If a Census block is within or touches a Tribal Land (as identified in the  2022 SB 535 Disadvantaged Communities definition) , it is automatically screened for inclusion in the demographic overlay, regardless of its household income status.

The Traffic Exposure Screen identifies low-income and or tribal area Census blocks that bear a negative traffic burden as measured by proximity, volume, and vehicle type for all interstates, highways, principal arterials, and minor arterials in the state — or a negative safety burden as measured through a statewide crash exposure calculation. The screen identifies Census blocks for inclusion with traffic proximity and volume at or above the 80 ^th  percentile and or blocks with a crash exposure score at or above the 80 ^th  percentile. Traffic exposure is used as a proxy for multiple environmental burdens, including diesel particulate matter, diesel exhaust, noise, and traffic safety impacts on communities.

Thresholds:

• Demographic Overlay criteria met, AND
• Traffic Proximity and Volume percentile >= .8 OR Crash Exposure percentile >= .8

The EQI Traffic Proximity and Volume indicator measures the degree to which neighborhoods are exposed to traffic. The indicator accounts for how close a given Census block is to traffic sources, the volume of traffic on said sources, and how much of the traffic is truck traffic.

The EQI Crash Exposure indicator measures the degree to which neighborhoods are exposed to crashes. The indicator calculates the severity-weighted density of crashes in each Census block in California. The EQI crash exposure indicator excludes crashes that occur on closed- access highways, as these crashes are less spatially relevant to their surrounding communities than crashes occurring on local roads or main street sections of the highway network. Crashes occurring on highway ramps are kept in the dataset since ramp crashes have a greater impact on local traffic and safety.

The Access to Destinations Screen identifies low-income and or tribal area Census blocks with poor relative multimodal access to destinations. This screen includes three unique access to destinations indicators, designed to evaluate gaps in transit access, bicycle access, and pedestrian access.

Thresholds:

• Demographic Overlay criteria met, AND
• Transit Access Ratio: Work < .12, OR
• Transit Access Ratio: Non-Work < .12, OR
• Pedestrian Access Ratio < .6, OR
• Bike Access Ratio < .6

The pedestrian indicator measures the ratio of pedestrian access to destinations to “ideal” access to destinations, where  crows-fly  calculations are used to calculate travel times instead of the actual network.

Currently, the bicycle and pedestrian access to destinations indicators are only calculated for non-work destination types, reflecting shorter, non-work trips commonly taken by bike or foot. Blocks with a ratio less than 0.6 are screened as having relatively poor pedestrian access to destinations.

The bicycle indicator measures the ratio of bicycle access to destinations on the  low-stress network  to bicycle access on the high-stress network. Blocks with a ratio less than 0.6 are screened as having relatively poor low-stress bicycle access to destinations.

The transit job access indicator measures the ratio of transit job access to congested auto job access. Blocks with a ratio less than 0.12 are screened for inclusion as having poor relative transit job access.

The transit non-work access indicator measures the ratio of transit non-work destination access to congested auto non-work destination access. Blocks with a ratio less than 0.12 are screened for inclusion as having poor relative transit non-work destination access.

The Access to Destinations Screen includes both the Traffic Exposure and Access to Destinations Screens and identifies the transportation-based priority populations of the state that are the most burdened by traffic exposure but also benefit the least from the multimodal transportation network (as measured by access to destinations).  It is important to note that while this screen looks at where the transportations burdens and lack of benefits intersect, depending on the specific use case, it may be more appropriate to use the Access to Destinations Screen or Traffic Exposure Screen. Moreover, if a given block is only screened by the Access to Destinations Screen or Traffic Exposure Screen---but not the Transportation-Based Priority Population Screen---it does not necessarily mean that the block is less-disadvantaged than one screened by the Transportation-Based Priority Populations Screen, only that it met the screening thresholds for both Traffic Exposure and Access to Destinations.

Thresholds:

• Demographic Overlay criteria met, AND
• Traffic Exposure Screen criteria met, AND
• Access to Destinations Screen criteria met

The map to the right illustrates the top-level EQI screen of every Census block in California. While a given block may overlap and meet the criteria for both the Traffic Exposure and Access to Destinations screens, it is shown on the map as a Transportation-Based Priority Population-screened block.

A web map showing all EQI Screens can be accessed  here . The mapping tool enables users to toggle screens on and off, as well as search for specific locations/addresses using the search tool.