Office of Safety and Operations 

Research and Development 

1

CARMA Platform(1)software 

is designed to facilitate the 

development and testing of 

CDA features in vehicles equipped with automated 

driving systems (ADS). This software allows automated 

vehicles to interact seamlessly with other vehicles, 

infrastructure, and other road users. The primary 

objective of CARMA Platform is to establish a foundation 

for interoperable connectivity across different vehicle 

makes and models, laying the groundwork for safe 

introduction of these tools on our Nation’s roads. This 

software also provides tools for cooperative research 

functionalities of ADS.

Key benefits include:

 Facilitating the continuous advancement of CDA 

technology, leading to safety and efficiency 

improvements in vehicle automation.

 Increasing accessibility for a broader range of users, 

allowing a diverse community of experts to 

contribute to its ongoing development.

 Reducing the costs associated with conducting 

research and development.

Saxton Transportation Operations Laboratory Cooperative Driving 

Automation (CDA) Tools to Improve Road User Safety 

 Road users encompass anyone utilizing and traveling 

roads, including pedestrians, bicyclists, and vehicle 

operators, among others. The tools provided by the 

U.S. Department of Transportation enable road users to 

navigate and interact with roads more safely and 

efficiently. The suite of tools includes CARMA 

PlatformSM,

(1) CARMA MessengerSM,(2) and CARMASM, 

1Tenth,(3) which aid in conducting research and 

testing of CDA technology.(4) Two of the tools within 

the suite, CARMA Platform and CARMA 1Tenth, are 

open-source software platforms, enabling public 

access that allows for software customization to meet 

users’ requirements.

© Getty Images Plus.

 Source: Federal Highway Administration (FHWA).(6)

TSMO = transportation system management and operations; RSU = roadside unit: 

ITS = intelligent transportation systems.

Figure 1. Illustration. CARMA products.(1,2,7,8,9)

CARMA Messenger(2) software is 

designed for nonautomated 

vehicles and facilitates 

communication with other transportation system users to 

enable them to engage in CDA interactions. This software 

leverages infrastructure to share data with other users, 

broadening access to the usage and benefits of the 

technology. CARMA Messenger supports research involving 

first responders and encourages transit participation in CDA. 

Key benefits include:

 Supporting research that involves first responders, 

which contributes to increased safety from alert 

messages and data. 

 Increasing communication between other vehicles, 

other road users, and infrastructure.

 Encouraging public transit involvement in CDA, 

potentially resulting in more efficient public 

transportation systems and reducing travel times.

 Enabling a broad range of vehicles, including 

nonautomated vehicles, to actively participate in the 

CDA network. 

Figure 1 shows how vehicles communicate with CARMA 

products.(5)
TITLE OF TECHBRIEF

2

The CARMA 1Tenth(3) research initiative integrates 

the CARMA Platform(1) onto smaller, simplified 

versions of full-scale vehicles known as 1Tenth 

vehicles (figure 2). These vehicles use a modified 

version of CARMA Platform, enabling researchers to conduct CDA research with 

a larger number of vehicles than full-scale connected ADS allow. This feature 

maintains the hands-on and demo-friendly nature of nonsimulated vehicles.

Key benefits include:

 Providing a safer environment for the initial development and testing by 

offering more control over the experimental conditions.

 Improving testing processes by allowing researchers to experiment on smaller vehicles without compromising 

CDA functionality, ensuring features work correctly before implementation in full-scale vehicles.

 Reducing reliance on test tracks, which can lower costs and allow for more extensive and varied testing scenarios.

 Accelerating research by engaging a larger community.

 Facilitating the testing of scenarios with large vehicle fleets, enabling the study of large-fleet CDA testing 

and performance.

 Creating a more equitable and affordable platform for researchers who do not have access to full-size, 

CDA-enabled vehicles.

GETTING STARTED

These previously mentioned tools can be accessed on GitHub,(1,2,3) allowing for collaboration and contribution among 

researchers. This collaboration will lead to a better understanding of CDA technologies, which helps accelerate market 

readiness of CDA.

GitHub provides a platform for users to collaborate, gain experience with CDA, and customize the software for their 

specific needs.

For technical support, please contact the CARMA Support Services Help Desk at CARMASupport@dot.gov. Each 

GitHub page also contains a section of frequently asked questions with solutions to common issues.

CDA TOOLS TO IMPROVE ROAD USER SAFETY

References

1. FHWA. n.d. “carma-platform” (software and configuration files in GitHub repository). https://github.com/usdot-fhwa-stol/carma-platform, last accessed 

April 12, 2023.

2. FHWA. n.d. “carma-messenger” (software and configuration files in GitHub repository). https://github.com/usdot-fhwa-stol/carma-messenger, last accessed 

October 3, 2023. 

3. FHWA. n.d. “carma-1-tenth” (software and configuration files in GitHub repository). https://github.com/usdot-fhwa-stol/carma-1-tenth, last accessed 

October 23, 2020. 

4. Vadakpat, G., D. Chou, H. Park, and S. Vu. 2022. “Cooperative Driving Automation (CDA) Research Program: Development, Testing, and Evaluation.” Public Roads 86, 

no. 3. https://highways.dot.gov/public-roads/autumn-2022/04, last accessed November 20, 2023.

5. USDOT. n.d. “CARMA” (web page). https://its.dot.gov/cda, last accessed May 30, 2023.

6. Lou, Y., A. Ghiasi, M. Jannat, S. Racha, D. Hale, W. Goforth, and P. Bujanovic. 2022. Cooperative Automation Research: CARMA Proof-of-Concept TSMO 

Use Case Testing: CARMA Cooperative Perception Concept of Operations. Report No. FHWA-HRT-22-062. Washington, DC: Federal Highway Administration. 

https://doi.org/10.21949/1521865, last accessed November 20, 2023.

7. FHWA. 2023. “V2X-Hub” (software and configuration files in GitHub repository). https://github.com/usdot-fhwa-OPS/V2X-Hub, last accessed April 13, 2023. 

8. FHWA. 2023. “carma-streets” (software and configuration files in GitHub repository). https://github.com/usdot-fhwa-stol/carma-streets, last accessed 

April 12, 2023.

 Source: FHWA.

Figure 2. Photo. CARMA 1Tenth.(3)

For more information, please contact the CDA Program at CDA@dot.gov

FHWA-HRT-24-036

HRSO-40/12-23(200)E

Recommended citation: Federal Highway Administration. Saxton Transportation 

Operations Laboratory Cooperative Driving Automation (CDA) Tools to Improve 

Road User Safety (Washington, DC: 2023) https://doi.org/10.21949/1521461