Highway Engineering

For the neighbourhood under examination, once the number of households

within each subgroup is established, the total number trips generated each day

can be calculated.

22 Highway Engineering

Example 2.2 – Calculating trip rates using category analysis

For a given urban zone, using the information on trip rates given in Table

2.1 and the number of each household category within it as given in Table

2.2, calculate the total number of daily trips generated by the 100 households

within the zone.

Solution

For each table cell, multiply the trip rate for each category by the number of

households in each category, summing all values to obtain a total number of

daily trips as follows:

T=+ +++++

++ ++++++

=

4104 23 1 85 2 215 2 202 14 31 14 38 1 26

934 1440 038548 764 042152 464

340 45

. . . . . . *.

. . . . . . . .

.

2.5 Trip distribution,

2.5.1 Introduction

The previous model determined the number of trips produced by and attracted

to each zone within the study area under scrutiny. For the trips produced by the

zone in question, the trip distribution model determines the individual zones

where each of these will end. For the trips ending within the zone under exam-

ination, the individual zone within which each trip originated is determined. The

model thus predicts zone-to-zone trip interchanges. The process connects two

known sets of trip ends but does not specify the precise route of the trip or the

mode of travel used. These are determined in the two last phases of the mod-

elling process. The end product of this phase is the formation of a trip matrix

Household pop. Available cars per household

012 +

14232

221414

31914

4 057

5 + 014

Table 2.2Category

analysis table (number

of households from

within zone in each

category, total

households =100)