Urban Transport Planning

1. In transportation planning process we should first define study area for which transportation facilities are being planned.
2. The transportation Planning can be national level, religion level or urban level.
3. For planning at urban level, the study area should embrace the whole continuous town and cities. 
4. The imaginary line representing  the boundary of study area is termed as external cordon. 

1. The external cordon line should cover the area which is already built up and  also likely to be developed during the design period. 
2. The external cordon line Should contain all area of systematic daily life of the people oriented towards the city center and should effect be 'commuter shed '.
3. The external cordon line should be compatible with previous studies of the area of studies planned for future.
4. The external cordon line should be continuous and uniform in its course so that movement cross it only once. 
5. The line should intersect roads where it is safe and convenient to carry out traffic surveys.

Trips:-

       A trip is a one way  person movement by a mechanised mode of transpose, having two trips ends, an origin(the start of trips)and destination (the end of the trip).

      Types of trips 

1. Home-based trips 

                   Home- base trips are these having one end of the trips [either origin or destination] at home of the person making the trips.                                                                        Examples:- consider trips from the home of the person making the trips of the place of work where the work and return to the home.

 Non-Home based trips:-

              Non-home based trip are those having neither end at the home of the person making the trips. 

       Examples:- The trip from the place of the work to the shop and return to the place of work.

Category Analysis:-

        Category analysis is based on the               etimate of the average number of                 trip  generated  by a set of define                   household group with the given range         of income, level of car ownership and           household structure. 

 Assumptions 

• The household in the fundamental unit in the trip generation process and most  journey begin or end in  response to the requirement of the family.
• The trip generated by the household depend upon the characteristics of that household andvits location relative to its required facilities.  Such as shape,  school and workplace.
• Only three factors are of prime importance for affecting the amount of travel to the household  I.e. car ownership,  income  and household structure. 

Advantages of pre -distribution modal split  are  given below:-

1. They are less difficult and less costly as compared to distribution methods.
2. The possibility of separate public transport and private distribution is afforded by this method because of the differing trip length.

Disadvantages of pre -distribution modal split are given below :-

1.  It does not consider the trip generation characteristics. 
2. It is to future development in inter zonal. 

Advantages of post- distribution modal split are :-

1. It is useful in situations where serious consideration is given to public transport planning. 
2. This is beneficial for long term decision making. 
3. The method considered private car and public transport usage on a zone to zone basis instead of a zonal basis as in pre - distribution models.

Disadvantages of post - distribution modal split are :- 

1.  This method is more complex if the number of zones are large.
2. The total person trip distribution is carried out before any modal choice is considered.

The assignment techniques are as follows:

1. All or Nothing assignment 
2. Capacity restraint assignment 
3. Incremental traffic assignment 
4.  Multiple routes assignment 
5.  Diversion curves 
6. User equilibrium assignment 
7. Dynamic assignment 
8. Probabilistic assignment 

 1. All or Nothing assignment:-

            In this method the trips from any origin zone to any destination zone are loaded on a single minimum cost, path  between them. This model is unrealistic as only one path between every origin to destination pair us utilized even if there is another path with same or nearly same travel cost. This model may also be used to identify the desired path. 

 2. Capacity restraint assignment:-

     It is a process in which the travel resistance of a link is increased according to a relation between the practical capacity of link and volume assigned to link. This system clearly restraint the number of vehicles that can be use any particular corridor, if the assigned volume are beyond the capacity of the network  and redistribute the traffic to realistic alternatives paths. 

3. Incremental assignment:-

  Incremental assignment is a process in which fraction of traffic volumes are assigned in steps. In each step, a fixed proportion of total demand is assigned based on All or Nothing assignment. Also, Incremental assignment is influenced by the order in which volumes for origin to destination pairs are assigned,  the possibility of additional bias in results. 

4. Multiple route assignment:-

    This method of traffic assignment of this method was developed by Burell. The main assumption of this method is that trip - maker does not know the correct travel time. The correct travel time is considered bevthe mean travel time. 

The movement of people and goods in a city, referred flow, is the joint consequence of land activity and capability of the transportation system to handle this traffic flow exactly like that principle of demand and supply. There is a direct interaction between types and intensity of land use and transportation facilities provided. Land use is one of the prime determinants of movement and activity therfore,  trip generation which needs streets and transport system for movement. 

The original Lowry was published in 1964 and since then several important extensions of the original model have been applied to practical planning problems  (Hutchinson 1974) . The Lowry model conceives of the major spatial features of an urban area in terms of three broad sectors of activity therefore employment sectors,  the population serving employment and the household sector.