Level of service is a measure by which transportation planners reckon the quality of service on transportation devices, or transportation infrastructure, generally linked to transportation time (the shorter, the better) and thus to speed. For another meaning of the term traffic engineering, please see telecommunications traffic engineering. ... In the fields of packet-switched networks and computer networking, the traffic engineering term Quality of Service (QoS, pronounced que-oh-ess) refers to the probability of the telecommunication network meeting a given traffic contract, or in many cases is used informally to refer to the probability of a packet...

The system works like a United States of America report card: A is the best, an empty road, B is slightly more congested, C has more congestion than B, and D is perhaps the level of service of a busy shopping corridor in the middle of a weekday - you can move your car around, but not very well and not very quickly; you are hemmed in by other cars and trucks. F is a full-blown traffic jam. (The above grading refers to highways; however, some professors in urban planning schools have proposed measurements of levels of service that take public transportation into account. Such systems would include wait time, frequency of service, time it takes to pay fares, quality of the ride itself, accessibility of depots, and, perhaps, other criteria as well.) Traffic jams are common in heavily populated areas. ... A professor giving a lecture The meaning of the word professor (Latin: one who claims publicly to be an expert) varies. ... Urban planning is concerned with the ordering and design of settlements, from the smallest towns to the worlds largest cities. ... A taxi serving as a bus Public transport comprises all transport systems in which the passengers do not travel in their own vehicles. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ...

In the past, some planners have aimed for an "A" Level of Service (and many still do in rural areas), but many transportation planners (especially proponents of public transit) recommend aiming for a "C" level of service (particularly in urban areas), one that would slow cars down and make roads safer for pedestrians (thus increasing the desirability of public transit if such transit has its own rights-of-way). To that end, transit-favoring planners recommend increasing population density in towns, narrowing streets, restricting car use in some areas, providing sidewalks, and making the scenery interesting for pedestrians. Look up Pedestrian in Wiktionary, the free dictionary. ... A sidewalk (North American English), or pavement or footpath (Commonwealth English), is a path, usually constructed of concrete (particularly in the United States, and Canada), asphalt, brick (particularly in Europe) or stone, designed for pedestrian traffic and often running alongside a road. ...