This disclaimer, the Terms of Use and the Privacy Notice together govern use of the site.
Research and training tool. Not for safety-critical use. Every tool on this site (the decoder, the message creator, the map builder, the live feeds, the simulator, the templates and the API) exists for research, education, testing and pilot planning. Nothing produced here should be broadcast on a public road without your own engineering review.
1. What the tools are for
ITS Roads, LLC built this workbench so that agency engineers, integrators, students and researchers can look inside SAE J2735 messages, learn how SPaT, MAP, TIM, BSM and the other messages fit together, draw a candidate MAP or TIM, watch live data, and rehearse an NTCIP 1218 push before touching real equipment. It is a classroom and a lab bench, not a production message server.
2. Not for safety-critical use
Messages produced or modified here (MAP, SPaT, TIM, BSM, PSM, SRM, SSM, RSM, SDSM and everything else) must not be used in safety-critical applications or deployed to public roads unless your agency, or the engineer of record for the deployment, has first done all of the following:
- reviewed the content against the agency's own survey data, signal timing plans and traffic engineering judgment;
- validated the encoded message against the published standard (SAE J2735_202409 and the application standards that apply, such as J2945/1, J2945/B, J2945/4, J3224 and CTI 4501) with tooling the agency trusts;
- run the message through the RSU or controller vendor's conformance and acceptance process, and the connected-vehicle program's own verification steps where one exists.
The codec on this site checks ASN.1 constraints. It does not know whether a lane really exists, whether a signal group matches the controller, whether an advisory is appropriate for the road, or whether a message is safe to broadcast.
3. No warranty
The tools, the guides, the templates, the API and every output are provided as is, without warranty of any kind, express or implied, including fitness for a particular purpose, accuracy, completeness or non-infringement. Data on this site may be incomplete, out of date or wrong. ITS Roads, LLC accepts no liability for any loss or damage arising from the use of the site or of anything produced with it. Use at your own risk.
4. Standards, licensing and affiliation
ITS Roads, LLC is not affiliated with, endorsed by or acting on behalf of SAE International, IEEE, NTCIP, NEMA, AASHTO, ITE or the United States Department of Transportation. SAE J2735, IEEE 1609 and NTCIP 1218 are the property of their respective owners.
The SAE J2735 standard itself, including its ASN.1 modules, is licensed from SAE International. This site does not redistribute the standard or its modules. The guides here are original explanations written by ITS Roads; field names and value ranges are quoted only as needed to describe how messages work. Buy the standard from SAE to do real work with it.
5. Demo and live data
The demo corridor, the simulator traffic and the sample messages are simulated. Any other live feed on this site carries data that a user chose to forward from their own equipment, and ITS Roads does not vouch for it. Positions, speeds and signal states shown here are for illustration and must not be used for navigation, enforcement, safety decisions or any operational purpose.
6. Privacy: uploaded packets, messages and feeds
Packets you paste or drop into the decoder are processed in memory and are not kept, apart from an event log line with the message type, size and your IP address. Messages, projects, RSU records, saved simulator setups, recordings and live feeds are stored per account so that you can come back to them, and you can delete them from the pages where you created them at any time. RSU SNMP credentials are stored encrypted. Feedback you send through the feedback page is stored with your IP address and, if you give one, your email, and is read only by ITS Roads staff. Nothing is sold or shared with third parties. Email ITS Roads to have an account and all of its data removed.
7. What is next
More messages and features will be added over time. If a message type, a field, a dataset or a workflow is missing, tell us which messages or features you are looking for. Requests from agencies standing up pilots go to the top of the list.
8. Help beyond the tools
ITS Roads, LLC is an intelligent transportation systems engineering firm in the Washington, DC area. If you need MAP and SPaT authored and validated for a real intersection, an RSU fleet configured and monitored, or a pilot planned end to end, see what ITS Roads does for agencies.
9. Terms of Use and Privacy Notice
The full legal terms, including the warranty disclaimer, the limits on liability, account approval and acceptable use, are in the Terms of Use. What the site collects, the cookies it sets and how to request deletion are in the Privacy Notice.
Last updated October 2026.