<Li> An express lane of a road is used for faster moving traffic and has less access to exits / off ramps . In other areas, an express lane may refer to a HOV lane (see below). </Li> <Li> A reversible lane (contraflow lane) is a lane where the direction of traffic can be changed to match the peak flow . They are used to accommodate periods of high traffic flow, especially rush hour where the flow is predominantly in one direction, on roads that cannot be easily widened such as over bridges . One or more lanes are removed from the opposing flow and added to the peak flow . </Li> <Li> An auxiliary lane is a lane other than a through lane, used to separate entering, exiting or turning traffic from the through traffic . </Li> <Dl> <Dd> <Ul> <Li> An acceleration lane or merge lane allows traffic entering a highway to accelerate to the speed of through traffic before merging with it . </Li> <Li> A deceleration lane is a lane adjacent to the primary road or street used to improve traffic safety by allowing drivers to pull out of the through lane and decelerate safely before turning off a surface street or exiting a freeway . </Li> <Li> A turn lane is set aside for slowing down and making a turn, so as not to disrupt traffic . By removing turning traffic from the through lanes, motorist safety is improved and delay is removed, but crossing distances for pedestrians are lengthened, increasing their exposure to collisions . </Li> <Li> A two - way center turn lane is a lane in the center of a roadway to allow drivers traveling in either direction to pause before turning across oncoming traffic (a left turn in right - driving countries, or a right turn in left - driving countries) while waiting for a gap in traffic . </Li> <Li> A passing lane is sometimes provided on busy two - lane roads to allow drivers to pass slower vehicles without having to cross the center line and risking a head - on collision . </Li> <Li> A climbing lane, truck lane, or crawler lane is often provided on steep mountain grades, in order to allow smaller vehicles to pass larger, slower ones . The lane is marked only on the uphill stretch and usually a short distance afterward (for regaining speed). </Li> <Li> An operational lane or auxiliary lane is an extra lane on the entire length of highway between interchanges, giving drivers more time to merge in or out . The lane is created when an entrance ramp meets the highway, and drops out (with an "exit only" sign) to become the ramp at the next exit . </Li> <Li> A transfer lane of a road is used to move from express lanes to collector lanes, or vice versa; it is somewhat similar to an auxiliary lane . </Li> <Li> A collector lane of a road is used for slower moving traffic and has more access to exits / off ramps . </Li> </Ul> </Dd> </Dl>

What is the standard width of a street