However, arriving at an optimum solution is an intuitive process because the planning process can , only predict the likely trip making which will arise if the plan is implemented. 然而，要想获得一个最优的解决方案，仍然是一个直觉过程，因为规划过程只能估未亲实现 划可能发生的出行情况。
城市轨道交通专业英语课程教案（第7周3—4节）
授课题目
Unit 2 Knowledge Fra bibliotekf Traffic
Lesson 6 Introduction to the Transportation Planning
process （下）
授课类型
讲授型
教学目标
Master the knowledge of decision to make a trip
( 3)Traffic assignment, which decides on which links of either the public transport or the highway network a trip will be made. 交通分配，确定种联络线既可采用公共交通又可采用一般道路网。
重 点
Decision to make a trip
难 点
Recently, a proportion of trips has been assigned to the alternative links between an origin and destination in an attempt to produce a realistic simulation of the real life situation。
The evaluation of the effects of these alternative proposals is the object of the third stage of the transportation planning process. 对于各项不同规划效果的评价属于交通规划程序的第三阶段工作。
( 1) Trip generation, which attempts to determine the connection between trip making and land-use factors noted in the planning inventory.出行产生，用以确定出行生成和规划资料清单中所标注的用地因素之间的关系。
Alternative plans may be evaluated , on a limited basis, by the estimation of the costs and benefits which arise if the plan is carried out.不同的规划方案则多是按照预估的费用和收益来进行评价的。
Recently,是时间副词，前置于句首，trips为主语，a proportion of 为名词+介词短语都表示一部分，has been assigned为现在完成时被动语态，to为介词，引出间接宾语the alternative links，between and 结构指明路段link的始末点，in an attempt to 表示尝试做某事，to produce 为动词不定式，后接a realistic simulation of the real life situation
( 4 )Modal split, by which a decision is made as to whichtravel mode a trip maker will use.交通方式划分，用以决定一个出行者将采用何种交通方式出行。
This decision may be made at the trip generation stage or frequently after trip distribution. 这项程序可以在出行产生阶段，也常常在出行分布以后进行。
The observed modal split relationship may be explained in terms of car ownership, relative travel costs between the alternative modes or on the basis of restrained private vehicle use.由观测所得到的交通方式划分关系，可以用车辆拥有者的情况、不同交通方式之间的相对出行费用或者以限制私家车使用的程度为依据来阐明．
On the basis of the travel cost, the decision is made on the alternative mutes between the origin and the destination. 根据旅程成本，来决定起终点之间的各种不同途径。
Trips are usually assigned to the mute of least cost. frequently measured by travel time. 出行常常选择费用最少的路径，而费用又往往是用旅程所需的时间来衡量。 Recently, a proportion of trips has been assigned to the alternative links between an origin and destination in an attempt to produce a realistic simulation of the real life situation.最近，在一个尝试性模拟实际情况的实验中，部分出行被分配到始点与终点之间可远的连接路段上。
it is usual to divide model building into the following interconnected processes which are described in detail in the subsequent sections.通常把模型划分成下列相互联系的步骤，对这些步骤将在随后的段落中详细说明。
教学小结
同学们对交通规划程序方面的知识并不熟悉，而本文又是篇英文文章，除了内容难懂外，还出现了大量的生词和短语，对学生而言，有很大的难度，因此要详细讲解。
With confidence in the ability of the developed models established, it is possible to forecast the travel needs of future land use and transport plans.如果确信已建立的各种模型的分析能力是可靠的，就有可能隕测未来上地利用和通规划的交通需求程度。
教学过程
结合同学们对城市交通规划的认知程度，根据教材详细讲述交通规划程序中的出行决定等相关知识以及文中生词、短语、及语法结构
作 业
Words and Expressions
2. Notes on the text
主
要
教
学
内
容
2.Decision to make a trip 出行决定
While the decision to make a trip is a complex process based on the availability of destinations, the travel facilities, the cost of travel and the journey purpose, 出行决定是个复杂的过程，它将以到达目的地的方便程度、旅行所乘用工具、旅行成本以及旅程目的等因素为依据。
( 2)Trip distribution, which determines the pattern of trips between the zones. 出行分布，用以确定各交通区间的出行方式。
It is usually postulated that the number of trips between zones is proportional to the size of the zonesof origin and destination and inversely proportional to some measure of their spatial separation.通常假设各交通区间交通出行的次数是和各起终点交通区域的大小成正比，而和空间上的距离成反比。
The trips are distributed, assigned and a modal split decision at the appropriate stage of the process carried out.出行被分布、分配并在进行过程的相应阶段中进行交通方式划分。
This allows checks to be made on the accuracy of the whole process because the flows assigned to the present day network may be compared with those actually observed on the network.因为分配到当前道路网的交通流量可与该道路网上实际观测的流量相比较，故可以检验出整个过程的精确。
After these interrelated processes have been set up, the existing land-use characteristics are inserted into the trip generation procedure.当各项相关的程序建立以后．现有用地性质嵌人出行产彗程序中。