Hay uno igual en el BUS VAO de la A6, yo creo que es medidor de ocupación.
https://www.google.es/maps/@40.4630053,-3.7774895,3a,75y,202.31h,84.98t/data=!3m7!1e1!3m5!1sSOHmSh4c2U9X8IJhtYTqow!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fcb_client%3Dmaps_sv.tactile%26w%3D900%26h%3D600%26pitch%3D5.018221103048447%26panoid%3DSOHmSh4c2U9X8IJhtYTqow%26yaw%3D202.31085389187325!7i16384!8i8192?hl=es&entry=ttu&g_ep=EgoyMDI1MDYxNy4wIKXMDSoASAFQAw%3D%3D