Here are some useful images for placards you may want to place on the sides of your test vehicle for the safety of your team and the public. We have gotten requests for these images over the years from other researchers, so we place them up on the site. There are based on US DOT conventions and the MUTCD standards; other countries differ. The link goes to a zip file with the entire set in high and low res images.
You can then have a local sign maker print these onto magnetic signs which you can then hang on the test vehicle when needed.
We cannot say enough about being careful when doing such things. When we test anything in our own shop that is not 100% routine driving, then we often use multiple flagman, temporary work-zone signs, constant radio contact, and at times even local law enforcement to keep the road segment safe and also to keep others away from our vehicle. A large secured parking lot is often a better place for such work. If you need basic survey equipment, signs, vests, etc, look on line or from Stakemill As a rule, traffic cones are best bought locally (because they are heavy and hence costly to ship in small numbers).