【正文】 個(gè)出現(xiàn)在下午。 例 3－ 3 某地四月 K月 4=， K日 4= ，實(shí)際觀測(cè)到該地某道路上 2023年 4月 13日（星期四）的交通量為 3558輛，試推算該地此道路 2023年的年平均日交通量。 ? ? 圖 3－ 1一年中小時(shí)交通量變化曲線圖 根據(jù)某地區(qū)交通量的日變系數(shù)和月變系數(shù)，以在觀測(cè)到某月某日的實(shí)際交通量后，大致預(yù)測(cè)當(dāng)年的年平均日交通量。試問該公路該修幾條車道？ Subhourly volumes and rate of flow Volumes observed for periods of less than one hour are generally expressed as equivalent hourly rates of flow. For example, 1000vehicles counted over a 15minute interval could be expressed as 1000 vehs/=4000veh/h. the rate of flow of 4000veh/h is valid for the 15minute period in which the volume of 1000 vehs was illustrates the difference between volumes and rates of flow. Time interval Volume for time interval(vehs) Rate of flow for time interval 5:005:15pm 5:155:30pm 5:305:45pm 5:456:00pm 1000 1100 1200 900 1000/=4000 1100/=4400 1200/=4800 900/=3600 5:006:00pm 4200 PHF=hourly volume/ max rate of flow ? Rate of flow (流率） defined as an equivalent hourly volume for a given interval (interval can be 5, 10, 15 minutes) ? Peak hour factor （高峰小時(shí)系數(shù)） ? DDHV (Directional Design Hourly Volume 設(shè)計(jì)小時(shí)流量 ) ? PCE and PCU （小汽車當(dāng)量） 2．高峰小時(shí)交通量 指一天內(nèi)的交通高峰期間連續(xù)1h的最大小時(shí)交通量。即 式中： Qi—— 周 i的平均交通量，在實(shí)際計(jì)算時(shí) iiid K???7171＝觀測(cè)日交通量周平均日交通量全年所有周一的天數(shù)量總和全年所有周一的日交通?iQ Volume ? Hourly volumes and peak hour volume （小時(shí)流量，高峰小時(shí)流量） Daily volumes, while useful for planning purposes, cannot be used alone for design or operational analysis purposes. Volume varies considerable over the 24 hours of the day, with periods maximum flow occurring during the morning and evening muter “ rush hours” . The single hour of the day that has the highest hourly volume is referred to as the peak hour. the peakhour volume is generally stated as a directional volume. Traffic going one way during the morning peak is going the opposite way during the evening peak, both sides of a facility must generally be designed to acmodate the peak directional flow during the peak hour. DDHV=AADT*K*D K: proportion of daily traffic occurring during the peak hour D: proportion of peak hour traffic traveling in the peak direction of flow For design , the proportion of AADT occurring during the 30th peak hour of the year, If the 365 peak hour volumes of the year at a given location are listed in descending order, the 30th peak hour is 30th on the list and represents a volume that is exceeded in only 29 hours of the year. 課堂練習(xí)： 某公路需要進(jìn)行拓寬改建，經(jīng)調(diào)查預(yù)測(cè)得該公路在規(guī)劃年的年平均日交通量為 50000輛小汽車 /日。用各個(gè)周日的交通量日變系數(shù) K日 表示交通量的日變規(guī)律。 ??????kiiiiQkQMA DTAAD TK1365113651＝月平均日交通量年平均日交通量月 一周內(nèi)日交通量的變化 在一周七天中，交通量也是逐日變化的。年平均日交通量與月平均日交通量之比，稱為交通量 月變系數(shù) M（或稱月不均系數(shù)，月?lián)Q算系數(shù)），即 式中： k—— 當(dāng)月的天數(shù)，可以取 3 2 29天； Qi—— 觀測(cè)日的交通量。 三、交通量的時(shí)間分布 交通量隨著時(shí)間變化而出現(xiàn)的變化，反映了社會(huì)與經(jīng)濟(jì)活動(dòng)等對(duì)交通的需求。但是在某段時(shí)間內(nèi)，兩個(gè)方向的交通量會(huì)有很大差別。 2．城鄉(xiāng)分布 一般是城市道路交通量高于郊區(qū)道路，近郊又高于遠(yuǎn)郊，鄉(xiāng)村道路交通量最低。 ???niiQnA DT11)(平均日交通量 ?????????71301365171)(301)(3651)(iiiiiiQWAD TQMAD TQAAD T周平均日交通量月平均日交通量年平均日交通量 二、交通量在空間上的變化 在同一時(shí)間或相似交通條件下，交通量在不同區(qū)段、不同方向和不同車道上其分布情況不一樣。 a mon application is to measure an ADT for each month of the year. ? ADT (Average Daily Traffic 平均日交通量 ) The average 24hour volume at a given location over a defined time period less than one year。 the number of vehicles passing a site in a year divided by 365 days. ? AAWT (Average Annual Weekday Traffic 年平均工作日交通量 ) the average 24 day year。時(shí)間的單位通常用“每天”或“每小時(shí)”表示。Chapter 3 traffic stream characteristics Traffic stream are made up of individual drivers and vehicles interacting with each other and with the physical elements of the roadway and its general environment. because both driver behavior and vehicle characteristics vary, individual vehicles within the traffic stream do not behave in exactly the same way, even in similar circumstances, because driver behavior varies with local characteristics and driving habits. Types of facilities uninterrupted flow interrupted flow Uninterrupted flow facilities have no external in terruptions to the traffic stream. Pure uniterrupt ed flow exists primarily on freeway, where there are no intersections at grade, traffic signals, ST OP or YIELD signs, or other interruptions exter nal to the traffic stream itself. Interrupted flow facilities are those that incorporate fixed external interruptions int