交通工程总结

L

N K =MADT

AADT =月K Part One —Define the following terms

Headway （车头时距）：is defined as the time interval between successive vehicles as they pass a point along the lane ， also measured between common reference points on the vehicles.

Peak Hour Factor （高峰小时系数）：The relationship between the hourly volume and the maximum rate of flow within the hour is defined by the peak hour factor(PHF).PHF=错误！未找到引用源。Flow of Rate Max Volume

Hourly

Perception-reaction time(PRT)(反应时间): from start of perception to the end of reaction (2.5 second is very common);it varies greatly from person to person ，from situation to situation.

Capacity: Maximum Hourly Rate at which persons or vehicles can traverse a point or a uniform section of a lane or roadway during a given time period under prevailing roadway ，traffic and control conditions.

Gap acceptance: is defined as the distance between the pedestrian and the approaching vehicle at the time the pedestrian begin his or her crossing.

Spacing(车头间距)：is defined as the distance between successive vehicles in a traffic lane ， measured from some common reference point on the vehicles ，such as the front bumper or front wheels.

Level of service(服务水平): is a quality measure describing operational conditions within a traffic stream ，

generally in terms of such service measures as speed and travel time ，freedom to maneuver ，traffic interruptions ，and comfort and convenience.

Percentile ：a value in a distribution for which the stated percentage of the population has a characteristics that is less than or equal to the specified value.

PCU(passenger car units)：a unit of measure whereby large trucks and turning movements are converted to passenger cars using multiplication factors.

T otal stopping distance ：The sum of the reaction distance and the braking distance.

TDM:is the application of strategies and policies to reduce travel demand

(specifically that of single-occupancy private vehicles), or to redistribute this demand in space or in time. TSM ：is a process for planning and operating a unitary system of urban transportation.

Delay ：is defined as “the addiional travel time experienced by a driver,passenger or pedestrian ”and with respect to field measurements,it’s the difference in travel time when a vehicle is unaffected by the controlled intersection or traffic incidents and when a vehicle is affected by the controlled intersection or traffic incidents.

TMS ：is the mean of the vehicle speeds observed at some designated point along the roadway.

SMS ：is the ratio between a length that a vehicle traveled and the average time lasted.

动视力 ：汽车运动时驾驶人的视力

设计小时交通量：将一年中所有8760（365*24）小时的小时交通量按由大到小的顺序排列时其第30位的那个小时的交通量，又称为设计小时交通量(Design Hourly V olume ，DHV ， 30HV)。

绿信比：一个周期的绿灯显示时长同周期时长之比。 交通密度：单位长度车道上，某一瞬间所存在的车辆数，辆/（km 车道）。 最大服务交通量：每一服务水平有其服务交通量范围。一、二、三级及四级上半段服务水平都有相应该级服务水平最差时的服务交通量，该服务交通量在该级服务水平中是最大的，故称为最大服务交通量。 行驶车速 ：车辆行驶过某段路程的长度与行驶时间的比。

月变化系数：

实际通行能力: 以理论通行能力为基础，考虑到实际的地形、道路和交通状况等的影响，确定其修正系数，再以此修正系数乘以前述的理论通行能力，即得实际道路、交通在一定环境条件下的可能通行能力。 视野（Field of Vision ）：眼球注意一点所能看见的空间范围,分静视野与动视野。

最佳周期时间：使交叉口各方向车辆通过路口的总延误最小的周期时间。