Road sign in the context of "Mileage sign"

A sign is an object, quality, event, or entity whose presence or occurrence indicates the probable presence or occurrence of something else. A natural sign bears a causal relation to its object—for instance, thunder is a sign of storm, or medical symptoms a sign of disease. A conventional sign signifies by agreement, as a full stop signifies the end of a sentence; similarly the words and expressions of a language, as well as bodily gestures, can be regarded as signs, expressing particular meanings. The physical objects most commonly referred to as signs (notices, road signs, etc., collectively known as signage) generally inform or instruct using written text, symbols, pictures or a combination of these.

The philosophical study of signs and symbols is called semiotics; this includes the study of semiosis, which is the way in which signs (in the semiotic sense) operate.

A park and ride, also known as incentive parking or a commuter lot, is a parking lot with public transport connections that allows commuters and other people heading to city centres to leave their vehicles and transfer to a bus, rail system (rapid transit, light rail, or commuter rail), or carpool for the remainder of the journey. The vehicle is left in the parking lot during the day and retrieved when the owner returns. Park and rides are generally located in the suburbs of metropolitan areas or on the outer edges of large cities. A park and ride that only offers parking for meeting a carpool and not connections to public transport may also be called a park and pool.

Park and ride is abbreviated as "P+R" on road signs in some countries, and is often styled as "Park & Ride" in marketing.

Tree care is the application of arboricultural methods like pruning, trimming, and felling/thinning in built environments. Road verge, greenways, backyard and park woody vegetation are at the center of attention for the tree care industry. Landscape architecture and urban forestry also set high demands on professional tree care. High safety standards against the dangers of tree care have helped the industry evolve. Especially felling in space-limited environments poses significant risks: the vicinity of power or telephone lines, insufficient protective gear (against falling dead wood, chainsaw wounds, etc.) and narrow felling zones with endangered nearby buildings, parking cars, etc. The required equipment and experience usually transcends private means and is often considered too costly as a permanent part of the public infrastructure. In singular cases, traditional tools like handsaws may suffice, but large-scale tree care usually calls for heavy machinery like cranes, bucket trucks, harvesters, and woodchippers.

Road side trees are especially prone to abiotic stress by exhaust fumes, toxic road debris, soil compaction, and drought which makes them susceptible to fungal infections and various plant pests like the spotted lantern fly. When tree removal is not an option, because of road ecology considerations, the main challenge is to achieve road safety (visibility of road signs, blockage-free lanes, etc.) while maintaining tree health.