4 wheel vehicle 4x4 car carrying driver icon land motor moving off-road pictogram sign symbol terrain transportation van vehicle wheel agriculture drive engine farm machine tractor work blue building bulldozer caterpillar construction digger earth rubber sand sky Soil track truck yellow acceptable access-denied access-limited advice advising alert allocated allocation approved authorised authorized automobiles behave black communicate communication denied directive entry-denied entry-prohibited horses horses-not-allowed horses-not-permitted information informing limited motor-cars no-access no-entry parking permission-denied permitted prohibited prohibition red restricted restriction restrictions safety signs unauthorised unauthorized vehicles warning white