8th Sem Notes

7/26/2019 8th Sem Notes

1/27

IMPORATNCE OF PUBLIC TRANSPORT

The demand for transport in the cities is linked to the various types of the trips undertaken by the

people. A large section of people make trips to reach their work places, students undertake trips

to reach the schools and colleges, there are trips which are related to recreational purposes,

religious purposes, shopping purposes, entertainment, social etc. As the cities grow in size the

number of trips increases in the city, besides the number of trips the trip length also starts to

increase, therefore there is a need to provide good transport to these people for easy urban

mobility.

The best and the cheapest mode of transportation for the large section of our population in all the

cities is the public transport system, various modes of public in different cities includes metro

rail, buses, auto rickshaws, taxis, rickshaws and local trains. As the income of the families has

started to increase in past two decades the dependence on the bus transport has started to

decrease due to the fact that many people can afford two wheelers and four wheelers now andprefer to make trips in their own vehicles. Liberalization followed with licenses to manufacture

of the different brands, types, etc., made it a buyers market offering innumerable choices to buy

two wheelers, this followed by attractive financing schemes. ven though the usage of public

transport has started to decrease but its importance to the cities can never be neglected. !ublic

transport still remains the cheapest mode of transport and it is safer than most other modes of

transport.

"sage of private vehicles may be possible for smaller families on certain particular occasions but

it is not possible for even small families to use private vehicles all the time so they also have to

make use of public transport. A large section of our society still cannot afford to travel in private

vehicles, so it becomes very important to have an efficient public transport system. !ublictransport is the sole mode of transportation for the school going children and also for a large

section of college students, many companies have assigned buses for catering to the travel

demand of their employees. #arious recreational trips are carried out in buses$ people prefer to

make religious trips in groups so the importance of public transport increases. !ublic transport

plays an important role in running the economy of the city as it caters to the various needs of

different sections of the society so it becomes very important to have an efficient public transport

system.

PROBLEMS ASSOCIATED WITH URBAN TRANSPORT

The problems associated with urban transport are of varying nature, some of them are enlisted

below%

Congestion% There has been a tremendous surge in the number of vehicles in &ndia in the

past two decades, the increase in number of vehicles is due to the increase in the income

of the people, having a vehicle in the family has brought lot of comfort and convenience

to the people but it has created larger problems, even though the number of vehicles has


2/27

increased by large proportions but the road width has not increased by same proportions

which leads to the congestion on the roads. The roads are occupied with vehicles beyond

their capacity which leads to congestion on the roads. The congestion leads to increase in

the travel time of the vehicles which decreases the overall efficiency of the transport

system followed by increase in noise and air pollution.

Growth in nu!er o" #ehi$%es% 'ith the increase in the income of the people there has

been a tremendous growth in the number of vehicles on the road. !eople have started

using two wheelers and four wheelers more fre(uently. The main reason for the increase

in the number of two wheelers are following

Two wheelers are very cheap as compared to other vehicles.

)e(uire very less space for parking

*ave very good maneuverability.

+ecrease the overall travel time, which includes walking time, and waiting time.

&ncrease in comfort and convenience. +ecreases the overall travel time as it avoids

walking and waiting.

*ighly reliable

Travel cost less compared to bus travel.

Liit&tions to ro&' wi'ening% There has been a tremendous growth in the number of

vehicles in past twothree decades but the expansion of the road network has not matchedthe increase in number of vehicles. There have been various factors which prevent the

expansion of roads$ the unplanned construction in the most cities has led to people

constructing various establishments on the land reserved for road expansion. The

situation is worsened by the improper design of roads which doesnt allow for

segregation of vehicles travelling at different speeds. -obility of all the vehicles is thus

limited to the speed of the slowest vehicle on the road. The average speed on the

angalore city during peak hours is /0 to 12 kmph.

De$%ining re%i&n$e on ro&' tr&ns(ort% The most important factor that has led to increase

in the problems of urban transport is that people have started to avoid the public transportsystem$ one of the factors for decreasing dependence on the public transport is the

inefficiency of the public transport and also the higher usage of private vehicles. The

percentage of two wheelers increased from 3.34 in /50/ to 6/.34 in 12//, whereas the

percentage of buses in the total volume on the road has decreased from //./4 to /./4.


3/27

De$%ining us&ge o" non)otori*e' o'es% The usage of non7motorized modes of

transport has reduced drastically in the past decades, people hardly use bicycle for

making trips anymore, and the walking which was a common thing of the past has

literally vanished. The reason for the decrease in non7motorized trips is due to the

increase in risk of walking and riding on the roads, the other reason for decrease in non7

motorized trip is due to the increasing length of the trips.

High %e#e% o" &ir (o%%ution &n' noise (o%%ution% The public transport has brought

people close and made different places in city easily accessible but the urban transport

has led to the high air pollution in cities. The petrol and the diesel cars used in the

cities release a

large amount of pollutants in the atmosphere which has led to degradation in the air

(uality of the cities causing various health problems to the people which are a matter

of concern for the government.

Ro&' &$$i'ents% There has been a tremendous increase in the number of accidents

with the increase in the number of vehicles on the &ndian roads. +ue to the careless

driving of few people the accidents have increased.

In$re&se in $onsu(tion o" (etro%eu (ro'u$ts% 'ith the increasing number of

vehicles the consumption of the petroleum products has increased several folds, &ndia

has to import large amount of petroleum products and a large part of the foreign

exchange is spend on it.

PROBLEMS ASSOCIATED WITH BUS TRANSIT

The bus transit is one of the most common modes of transit in urban areas, it is considered as life

line of the angalore city. Large number of commuters have an easy access to this mode of

transportation, even after having any benefits this mode has few disadvantages also. 8ew of the

problems associated with bus transit are%

Transport inade(uacy i.e not matching with demand.

9entralization% concentrated mainly to centre of the cities.

8ares% due to stage system which makes it costly for shorter distance travel and

economical for longer distance travel.

&nappropriate location

us stops are not scientifically planned and provided.

us fre(uency is low or unevenly distributed.

Longer waiting time at the bus stop


4/27

Lack of information at the bus stop about bus timings, route details, bus number passing

through that stop.

Takes too long to get a seat in the bus

uses are overcrowded

&nade(uate facilities at the bus stops like lack of sheltered stops, lack of seating

arrangements etc.

9ommon entry for exit for commuters% leading to friction and delay to both boarding and

alighting passengers.

The efficiency of bus transit system depends upon the access that passengers have to the bus, bus

stop is the point that provides access to the passengers to board or alight the bus, if the bus stops

are located at the proper places then a higher number of commuters will have easy access to the

buses and therefore the efficiency and occupancy of the buses will increase. :n the other hand ifthe bus stop spacing is improper lot of people will not have an easy access to the bus stop and

therefore affects the efficiency of the transit services. Therefore it becomes necessary to locate

the bus stops at the proper places with an ade(uate spacing between them so as to increase the

transit efficiency.

OB+ECTI,ES OF IDEAL BUS STOP LOCATION

A bus stop should be easily accessible for all the passengers who use the bus, bus stop

layout should be such that the dwell time of the buses at the bus stops is reduced. :ther vehicles like scooters, autos and private vehicles should be prevented from parking

at the bus stops$ the various curb street factors which affect the boarding and alighting

from the buses should be removed.

The bus stop should provide with minimal facilities like shelter, sittings, dust bins etc.

There should be a signage showing the availability of other modes of transport and also

information system about the bus arrivals.

The layout should be such that buses can be parked near to kerbs and passengers can

board and alight from the buses easily. us stops should be connected with footpaths for

easy access.

us stops should not be covered from all the sides as it will prevent the passengers fromseeing the buses coming towards the bus stops.

CONCERNS ASSOCIATED WITH LOCATION OF BUS STOPS

The ma;or concerns associated with location and design of bus tops are as follows%

Per"or&n$e o" Tr&nsit Agen$-% Location of bus stops has a significant effect on the

performance of the transit agency which operates in the city. The location of bus stop determines


5/27

the usage of the transit agency. Travel time of the bus can be divided into four parts, access time

to reach the bus stop, waiting time at the bus stop, on board travel time, time taken to reach the

destination after alighting from the bus. The main goal of the transit agency is to locate the bus

stops in such a way that the total travel time is decreased.

Tr&""i$ "%ow. Location of the bus tops has a significant effect on the traffic flow. 'hen the bus

stops at the bus stop it reduces the capacity of the road, width of the bus is 1.< meters and with

clearance it reduces the road to one lane of width =.0 meters for the time, the bus dwells at the

bus stop one lane of the road is blocked by the bus. *9- 12/2 gives a value of bus blockage

time and it is about /0 seconds for each bus stop. >umber of buses arriving simultaneously at the

bus stop also has an effect on the traffic flow$ dwelling of = buses together at the bus stops

creates a bottle neck and thus blocks all the movement of the traffic.

S&"et-% ?afety refers to being certain that no harm will occur under defined conditions. At a bus

stop the safety should exist between the buses, passengers and other vehicles. 'hile waiting at

the bus stops the passengers should feel safe, the bus stops should be located at such places

which dont cause problems to people while crossing a busy street.Se$urit-% The availability of various amenities at the bus stops like lighting makes passengers

feel safe driving at night, also if the bus stop is located near a residential area or any other land

use people feel safer.

CONCEPT OF BUS STOP OPTIMI/ATION

'hen the spacing between the bus stops is large then the travel time in the buses is less, this is

because buses have to make lesser stops when the spacing is larger. There exists a relation

between the travel time and the bus stop spacing, if the stops are located closer to each other,

then the commuters have to walk lesser distance to reach the bus stops to board the buses but

closer spacing results in larger travel time as buses have to make larger number of stops to cater

to needs of people resulting in loss of time to all bus occupants. Larger spacing between the bus

stops leaves loopholes in the coverage of buses as there exist gaps in the coverage and many

people find it hard to walk larger distances to reach bus stop, when the stops are spaced closer

there occurs an overlap in the coverage and the number of stops increases which increases the

bus travel time.


6/27

EFFECTS OF OPTIMI/ATION OF BUS STOP SPACING

'ith the growth of private vehicles on the roads the overall problems of the cities have

magnified by large proportions, this tremendous growth of vehicles has led to increase in travel

times in the cities due to the delays enroute because of high congestion on road, in angalore

city the average speed during peak hours is about 12 @mph this lead to an tremendous waste of


7/27

time of all the people of the city, it is not easy to reduce the number of private vehicles on roads

but people can be made to shift their mode of transportation which will solve a large portions of

the urban transport problems. 8or people to make a shift from private vehicles towards the public

transport it becomes necessary to make the public transport attractive. 'hen the bus stops are

located at optimal distance the accessibility to the bus stops is easy, people are not reluctant in

walking to the bus stops for catching the bus.

:ptimization process helps in creating a model for urban transport which reduces the

overall travel time of the passengers$ this will help in saving a lot to time of commuters. &n the

optimal spacing model the headway of buses is properly established and this proper headway

between the buses helps to reduce the overcrowding in the buses and helps to prevent the bus

bunching. !eople know about the arrivals of the buses and dont crowd for one bus as next bus is

expected within few minutes.

y optimizing the spacing of bus stops it is possible to reduce the overall travel cost of the

passengers. The operating agencies can make large profits by optimization of bus stop spacing,optimization of bus stops leads to decrease in the fleet size of the transit agency$ it decreases the

dwell times of the buses at the stops therefore reducing the wastage of fuel which is spent during

idling of the buses at the bus stops. Acceleration and deceleration of vehicles for each stop also

increases. These savings can be used to reduce the travel cost of the passengers which is a direct

benefit to the commuters. The overall facilities at the bus stops can be improved which is the

secondary benefit to the commuters.

The effect of spacing between the bus stops has been a critical issue. &f the bus stops are

closely spaced they increase the in bus travel time of the commuters, large spacing of the bus

stops leads to inefficiency in the coverage. The fre(uent stopping of the bus due to close spacingleads to disruption of the traffic flow. +ifferent methods have been used to determine the optimal

spacing of the bus stops. Anthony A. ?aka


8/27

Ta ,d=[PsNs+PcNc+ (Ps+PcPsPc )Nsc+1 ] u (a+d )120ad

'hereTa ,d=time attributedaccelerationdeceleration

PC=probability that a busis stopped by traffic signalat stoplocation;

Ps=probability that a bus makes a stop at regular bus stop location;

PsPc=joint probability of bus stoppingat traffic signalsoverlapping withbus stops $

Ns=number of bus stops considered isolated traffic signals;

Nc=number of signalized traffic intersectionsconsidered isolatedregular bus stops ;

Ns , c

=number of bus stops overlapping with signalized traffic intersections;

N=Ns+Nc+Ns ,ctotal number of potential stopson the bus route

a C normal acceleration rate of the bus

d C normal deceleration rate of the bus

E0u&tion "or 'we%% tie &t !us sto(s%


9/27

The transit agency for the angalore city is -T9 and the agency is currently running in loses

because the income of the agency is falling short of the operating cost. Therefore there arises a

need to identify to identify cost effective measures of sustaining a high system performance.

&t has been found that the operational performance of the transit agencies can be improved

significantly by optimizing the spacing of the bus stops. The highway capacity manual contains

formulas for analyzing the various transit operational parameters$ however these formulas do not

include transit stop spacing as an operational parameter. The spacing of the bus stops clearly or

the number of stops, clearly affects operating speed of the system, the headway, the potential

capacity and the fleet size. 'hen the bus stops are closely spaced and passengers can easily

access these stops, however the problem of having closely spaced bus stops is that there are

fre(uent stops, increased travel times, increased emission rates increased stress on the driver, and

increased disruption on the traffic flow. *owever if the bus tops are spaced at larger spacing the

problem that arises is that the accessibility to the bus stops decreases and the commuters have to

walk more. The basic aim of the transit agency is to maximize the accessibility and minimize

tradeoff. The preferred policy for transit stop spacing is one that attempts to balance the two

issues.

Transit operators decide on the policy, service headway and then determine the fleet size. &t is

hypothesized that it is possible to reduce the re(uired fleet size by optimizing the spacing

between bus stops.

The review into the past research has revealed two categories of work. The first study is related

to minimizing the total travel times and maximization of transit patronage. This approach gives

an insight into the benefits that are derived from the optimization of the bus stop spacing. The

second category of research involves studying the effect of the bus stops on the speed,

acceleration and deceleration of the other vehicles in the interrupted flow.

This pro;ect work is the extension of both the categories of previous research. The optimization

of bus stop spacing can be used for determining the fleet size. y using the bus stop spacing as a

factor to determine the fleet size it is possible to reduce the fleet size which in turn can reduce

the transit operating cost fixed cost of procuring additional buses and operational cost per busB.

?mall spacing between the bus stops leads to increase in the travel time due to fre(uent stoppage

at bus stops. :n the other hand if the spacing between the bus stops is large then the buses can

attain a maximum speed which is the allowable speed limit on the road. *owever there exists a


10/27

bus stop spacing threshold beyond which the operating speed will not increase. 8rom the various

studies conducted throughout the world it has been found that people are not willing to walk

more than 322 meters to reach a bus stop, the studies in &ndia have shown that the optimal

spacing should be about E22 meters. These findings were used as guidelines for determining the

optimal spacing for the pro;ect work.

The following procedure is used to determine the optimal spacing of bus stops

8irst the fleet size for the maximum bus stop spacing was calculated

?econd the assumed bus stop spacing was then reduced gradually until a lower threshold

value that preserves the calculated fleet size.

The actual bus travel time, which is directly related to bus stop spacing, may vary due to various

unstable external factors such as weather, traffic and even bus operators attributes. Therefore in

the actual application of the model the spacing may be increased slightly than the optimalspacing.

The model development process is carried out in two stages$ first the bus travel time that

determines the fleet size re(uirements was computed by dividing the time into four main

components$ acceleration deceleration time$ delay time at stops $ delay time at traffic signals$

and unimpeded travel time involving cruise speed. ?econdly a sensitivity analysis was carried

out by gradually varying the bus stop spacing until the optimal bus top spacing was determined.

METHODOLOG2

The first step in the pro;ect was to determine the bus travel time , the bus travel time is divided

into four components$ acceleration deceleration time, dwell time at bus stops , dwell time at

traffic signals and one way unimpeded travel time.

ACCELERATION AND DECELERATION TIME

+escription$ach bus stop is associated with two activities which affect the total travel time of the bus, the

first is the time spend in decelerating the bus to stop it at the bus stop and the second is the time

spend in accelerating the bus when it starts to leave the bus stop after stopping at the bus stop.The total number of accelerating and decelerating activities along the route is found out and the

total time spends in accelerating and decelerating along the route is calculated.

METHODOLOG2

The acceleration deceleration time was calculated as follows%


11/27

A strip of 02 meter length on the route was selected, the strip was divided into 0 strips of /2

meter length each, the time taken by the bus to traverse a distance of /2 meters was found out by

using a stopwatch, and the speed of the bus was calculated from the formula%

"peed=distance

time

The speed on each strip was calculated using this method, the acceleration and the deceleration

of the buses was found out from the following formula

#2$

2=2a"

Let the displacement from the stop position to cruise speed and the cruise speed to stop position

is denoted by %a and %d respectively. Therefore for cruise speed v we have

%a=#

2

2 a

%d=#

2

2 d

'here a C normal acceleration rate of the bus

d C normal deceleration rate of the bus

Therefore the component of the displacement during which the bus accelerates or decelerates is

given by

%a , d=#2( a+d2 ad)

The total terminal to terminal travel time attributed to acceleration and deceleration of a

bus is determined as under

Travel time attributed to acceleration and deceleration C combined probability of bus

stopping at bus stops and traffic signalsB F dwell time for each stoppage


12/27

-athematically it can be written as

Ta ,d=[PsNs+PcNc+ (Ps+PcPsPc )+1 ][u ( a+d )120ad]

'here

Pc=probability that a bus is stopped by trafficsignal at stop location;

Ps=probability that a bus makes a stop at regular bus stop location;

PsPc=joint probability of bus stoppingat traffic signalsoverlapping withbus stops $

Ns=number of bus stops considered isolated traffic signals;

Nc=number of signalized traffic intersectionsconsidered isolatedregular bus stops ;

Ns , c=number of bus stops overlapping with signalized traffic intersections;

N=Ns+Nc+Ns ,ctotal number of potential stopson the bus route

PROBABILIT2 OF BUS STOPPING AT A BUS STOP$

+escription$

'hile traversing the route the bus has to make stops at the designated stops, the buses may stop

at all the stops or a bus may skip a particular stop. The bus stopping at a bus stop or skipping a

bus stop depends upon the passengers waiting at the bus stops or the passengers who want to

who want to get down at the bus stop. The probability of bus stopping at the bus stop is given by

the formulae

P=1&[e' ]

'= ![( f) (N s+N s , c+1 )]

G is the average demand boarding or alightingB per bus stop for operating headway$

f C E2h or service fre(uency on bus route$

hC operating headway expressed in minutes$ and


13/27

H C hourly demand on bus route

BUS SOP DWELL TIME

+escription$

The dwell time of the bus on each bus stop along the route is found out. This time

includes the time spend in serving all the passengers at the bus stops i.e. the time taken by

passengers to board or alight from the bus at the bus stop and the time taken to open and close

the doors of the bus.

METHODOLOG2.

The time taken by passengers to alight and board the bus is found out along with the

average time it takes to open and close the door of the bus by travelling in the bus along the route

and the average time the bus spends at each bus stop is noted.

-athematically the total dwell time at the bus stops is calculated as% ref


14/27

N=(2Tbus )

h

> is the re(uired fleet sizeh is the headway

REDUCTION IN TRANSIT OPERATION COST B2 OPTIMAL BUS STOP LOCATION

+ue to rising costs and decrease in the subsidies provided by the governments the

transportation funding is becoming very tough, therefore receiving a high level of attention from

transportation departments. The few important issues that need attention include congestion

mitigation, travel time, air (uality improvement and reduction of operating costs.

!ublic transit is considered as being environmental friendly because of the high carrying

capacity. &t has been found that a bus can carry same number of passengers as carried by


15/27

The relation between spacing total cost of access and riding per unit length is parabolic in

nature as shown in figure below. As the spacing between the bus stop increases the total cost

decreases as the bus has to make fewer stops, the total cost goes on decreasing as the stop

distance increases and it reaches a point where the cost is minimum, this spacing gives the

optimal spacing of the bus stops, if the distance is further increases the cost starts to increase as

the bus stops become inaccessible to passengers therefore the number of transit users decreases.

!arameters for setting up of e(uations

s=stop spacing

p=number of passengersdistance

ps=e(pected number of passengers alightingboarding per stop

Assumptions for development of model%

>umber of passengers boarding or alighting at a stop is !oisson distributed$

Travel demand is uniformly distributed over s$

Average access distance Cs4

MODEL DESCRIPTION.

The total cost function is divided into two cost functions%

Access cost

)iding on board and stopping cost

A$$ess $ost.

The access cost is related to the passengers walking distance, the access cost depends upon

the number of people boarding and alighting at the stop, and on the access speed v. the access

cost in terms of length can be written as% ref 0B


16/27

Ca=nl 'a=(ps )( (s4 )( ()a

v)=ps2 )a

4 v

n=average number of passengersboardingalighting per stop=ps

l=average distance=s4

'a=cost per unit distance

v=passenger access speed

)a=averagecost per personfor access

RIDING AND STOPPING COST.

The riding cost of the passengers is determined by the total time spend by passengersriding in the bus and the stopping cost is expressed as the time spend by the passengers at the

various stops. The riding and stopping cost can be formulated as% ref 0B

(1eps)

Cr=N(tr+tl )' r=N ( ( s#+ P r)( ( )r )=Ns)r

#+N )r

N=number of passengerson the vehicle

tr=ridingtime

tl=lost time


17/27

#=vehiclecruise speed

=timeloststopping serve passengers

1eps=probability that bus stops at the bus stop

)r=averagecost per unit time per person

Then the average cost per unit length s is given by% ref 0B

C=( Ca+Cr )

s =[{(ps )a )4 v )r pN}+{(1e

ps)ps }]

*et +=(4 v)r)a)pN

This is a single unit less (uantity

)r)a=value of ridingtime comparedaccess time

pN C number of passengers with origins and destinations that lie within a distance one can

travel by access or walking in lost time D

Then the average cost per unit length becomes

C=[( ps+)+{(1eps )

ps }] )r pN+N )r#


18/27

8rom the above e(uation it is clear that bus stop spacing s is independent of # and IrDp>.

Therefore the bus stop spacing s is solely dependent on J. The idea of optimizing bus stop

spacing with the reduction in the total cost can be formulated as under%

C o=[ps+ + (1eps)

ps ]

The minimized total cost is obtained from the two functionsps+ and

( 1eps )ps

the total

cost reaches a minimum when functions

(1eps )ps

ps

+become e(ual.

The probability of a bus stopping at the bus stop in our case is / as we suppose that buses make a

stop at every bus stop, therefore for our case /7e7psB becomes /. Therefore the e(uation takes the

form

ps

+=

1

ps

+=p2 s2

Therefore - J C ps

ut J C4 v

)r

)apN


19/27

Therefore s +

p

"=(4 vpN

)r

)a)pKiving the values to all the above variables we get ?

ANAL2SIS PART 34 wor5e' e6&(%e &''ition&% 7

!art / of the analysis is associated with helping in reducing the number of buses plying on the

route. The various field values have been used to reduce the fleet size for one hour on the route.

Total distance to be travelled +C 3.1 kilometers C 3122 meters

Acceleration rate of bus a C 2.3 ms1 from field studiesB

+eceleration rate of bus d C 1.0 ms1from field studiesB

>umber of traffic signals >cC 5 from field studiesB

>umber of isolated bus stops >sC 5 from field studiesB

>umber of bus stops at signalized at intersections >scC 1 from field studiesB

Number of buses running per hour = 24 (field studies)

Average occupancy of buses = 1 (field studies)

!ourly passenger trips " = Number of buses running per hour (24) # average occupancy of buses (1)

= 24 # 1= 1224

Average *eadway hM C = minutes average value from field studiesB

D C average service time per passenger C E seconds estimated from field observationsB


20/27

k C average time to open and close the door C < seconds estimated from field observationsB

f = service fre(uency on route C60

h C 12

?peed of the bus on the route C 2kmph C E.5< ms

An&%-sis

Ste( 3.

Average spacing for the existing conditions

%=.N=

$200

%+%+2=

$200

20 =410meters

% is the spacing between the potential stops

!robability that a bus is stopped by traffic signal

Pc=probabillityof bus stoppingat the traffic signal=Cg

C

(1200 )

0 =0&$'

!robability that a bus makes a stop at the regular bus stop location

Ps=1&[e' ]2

'= !

[( f) (N s+N sc+1 )]


21/27

'=1224

[( 60') (2+%+1 )]

G C 0./

Therefore P s=1&[e&1 ]2

!sC probability of bus stopping at the bus stopsC 2.555

Ste( 8% stimation of bus travel time%

!art of travel time attributed to acceleration and deceleration%

Ta ,d=[PsNs+PcNc+ (Ps+PcPsPc )Nsc+1 ][ u (a+d )120ad]C [(0&%%%(%+0&$'( %)+(0&%%%+0&$'&0&%%%( 0&$' )( 2+1 ]

( [6&%4(0&$+2&

120( 0&$( 2& ]Ta ,d=traveltimeattributed accelerationdeceleration C /.E< minutes

+well time at bus stops%

Ts=

[P s (Ns+Ns , c+1 )

][(qs

f)(

60

)+

k

60

]qs=

!Ns+Nsc+1

=1224

12 =102


22/27

[0&%%%( (%+2+1 )] [( 10224)( ( 460 )+( 460 )]Ts=.well time at bus stops=4&$minutes

+well time at traffic signals%

TC=PC(Nc+Ns , c ) [0&0( (Cg )]

60

TC=[0&$'( (%+2 )]( [0&0( 120&060 ]

TC=(6&41' )( (0&$' )

TC=.welltime at traffic signals='& minutes

"nimpeded one way travel time%

T/=(.u)& Ta , d

To=$200

6&%4(60&1&64

To C /3.20 minutes

Total time taken for one way travel%

Tbus=Ta , d+Ts+Tc+To+Tm

Tbus=[P sNs+PcNc+(P s+P cPsPc )+1 ][ u (a+d )120ad]+[P s (Ns+Nsc+1 ) ]


23/27

[( qsf)( 60 )+ k60 ]+[PC (NC+N" ,C)[0&0 (Cg )]

60 ]+[(.u)+Ta , d]+Tm

Tbus=1&64+4&$+'&+1$&0+

C =1.=/ minutes

9alculation of fleet size%

N=2( cycle length

0eadway =

(2Tbus )h

N=2( '2&'1' =22&2=22

Therefore from the analysis it is possible to reduce two buses for one hour on the route.

Sings Due To Re'u$tion in F%eet Si*e.

Assuming that the buses run for a period of /< hours, and then we have

Total number of buses that can be reduced on one route for each hour

14( 2=2$ buses per day

:perating cost of bus per day C )s


24/27

y carrying out the optimization of the routes, it is possible to reduce the fleet size and

the number of bus stops on the route. The spacing of the bus stops has a (uite significant effect

on the efficiency of the public transport systems, by properly spacing the bus stops it is actually

possible to reduce the overall travel time which will lead to savings in time for the passengers

and also help to reduce the operating cost of the agencies. ut the bus stop spacing should be

such that it doesnt discourage the commuters from using the public transport, if the bus stops

have large spacing between them then the commuters may not prefer to walk the long distance in

order to reach the bus stop to catch a bus, on the other hand if the bus stops are located fairly

close to each other the buses have to make fre(uent stops which increases the total ;ourney time.

ased on the study carried out it is possible to change the spacing of the bus stops on the

route without affecting the commuters and bringing it to the standards specified by &ndian road

congress, by using the total cost function it is possible to reduce the number of bus stops on the

route which will help in minimizing the overall costs.

The total cost function is composed of two parts$

Access cost 9a

)iding cost 9r

Access cost can be mathematically written as

Ca=nl'a=(ps )( (s4 )(()av)=p s2

)a4 v

)iding cost can be written as

Cr=N(tr+tl )' r=N ( ( s#+ P r)( ()r )=Ns)r#+N )r(1e

ps )

These two e(uations can be combined to get a final e(uation of the form

C=( Ca+Cr )

s =[{(ps )a )4 v )r pN}+{(1e

ps)ps }]


25/27

&t is possible to introduce a dimensionless (uantity J , where J is e(ual to

+=(4 v )r)a )pN

The final e(uation for the total cost takes the form

C=[(ps+)+{(1eps )

ps }] )r pN+N )r#8rom the above e(uation it is clear that bus stop spacing s is independent of # and I rDp>

.therefore the bus stop spacing s is solely dependent on J.The idea of optimizing bus stop

spacing with the reduction in the total cost can be formulated as under%

Co=[ps+ + (1eps )

ps ]

The final e(uation for the spacing becomes

"=(4 vpN

)r

)a)pThe values for different variables is as under

)r

)a=value of riding time comparedaccess time=6

# C walking speed C /.1 ms

D C time taken to serve each passenger C E seconds field valueB

> C number of people in bus occupancy of bus C 02


26/27

p=density= peopledistance

=6

"=4( 1&2( 6(6(0( 6

6

Therefore ? C


27/27

Total cost saved on the route due to optimization which leads to reduction in fleet size and

number of bus stops is e(ual to

"avings='$00000+10000=2s'%0000 1 '&$ crores

8th Sem Notes

Documents