Transportation Engineering

Dr. Shaker Mahadeen Page 1 Osama Azmi

INTRODUCTION :

I.T.E : Institute of Transportation Engineering .

Transportation Engineering :

Functions of Transportation :

1- Links residents with employments .

2- Links producers of goods with their users .

3- Provides the options for work , shopping and recreation , and give access to

health , education , and other facilities .

1- Airways : Is used in small shipment of light and expensive goods .

( Speed of delivery is a controlling factor ) .

Factors Affecting the Design of a Location of Airports :

1- Satisfactory accommodation for arriving and departing passengers .

2- Efficient handling of cargos .

3- Sufficient parking space .

4- Good surface transportation service between the airport and the center of

departure destination .

2- Highways : Affecting Factors to Design a Highway :

1- Curvature .

2- Gradient .

3- Drainage .

4- Soil conditions .

5- Safety .

6- Sight distance .

7-

8- Surfaces .

9- Traffic impact .

The application of technological and scientific principles to planning

operations and management of facilities for any mode of transportation in

order to provide for the safe , rapid , comfortable , convenient ,

economical and environmentally compatible movement of people and

goods .


1- Origin destination and delay studies (OD) .

2- Traffic senses .

3- The expected traffic load within the lifetime of the highway pavement .

4- The relation of the highway itself and the future development of the system

.

5- Enough right of the way .

3- Pipelines : Provide direct low cost dependable movement of petroleum products and water .

Advantages :

1- There are no empty vehicles .

2- Delivery is continuous and the amounts to be delivered can be predicted

accurately .

3- The system is in the ground and the maintenance is low .

4- Theft is almost impossible and the labor required for operation is

comparatively small .

4- Railways :

5- Waterways : Is used when a low cost cargo needed and the time is not a controlling factor .

Transportation :

From land use and traveling demands .

Transportation Cycle :


Land Use :

It is described in terms of characteristics intensity and the location of land use

activity .

Accessibility :

Is a function of zonal attraction and ease of access , or a relative measurement

depends on:

a) Activity type .

b) Transportation mode and sense .

c) Location of a zone .

d) Time of the day .

Demand of function depends on :

a) Ease of travel .

b) Attraction of an area .


c) Accessibility of an area .

Travel Demands :

Is the number of trips based on some basis ( year, day , etc ).

Ease of Travel depends on :

a) Travel time .

b) Travel cost .

c) Comfort , safety , … , etc .

Travel Impedance :

1- Travel time .

2- Travel cost .

Attraction of an Area Depends on :

a) Type of activity opportunities .

b) Number of activities .

c) Quality of the area .

Accessibility of an Area : ( More accessible more attractive ) .

Development Alternations :

1- Density :

a) Low b) High . 2- Development Patterns :

a) Dispersed b) Concentrated . 3- Arrangement of Activity :

a) Segregated b) Mixed .

Planning Operations :

1-The tremendous dependence on the automobile and the reaction of this

dependency to from and the location of people and their jobs .


2- The evolution of the public transportation system capable of serving the

entire area effectively .

3- The capability of government and its policies to provide a transportation

system that is equitable to both car owners and careless .

4- The combination of new technologies and efforts to design a more

satisfying system in a long run .

5- Complexities of new problems due to the uncertainty of energy supplies.

6- Solving transportation problems through the public and private sectors

and the cost implications of alternative federal policies .

Traffic Signals : Types of Traffic Signals :

1- Pretimed traffic signals .

2- Semi-actuated traffic signals .

3- Fully traffic signals .

Geometric Design Concepts : Is a design of visible dimensions of the highway with the objective of forming or

shaping the facility to the characteristics and the behavior of driver , vehicle , and

traffic .

1-Highway Engineer 2-Traffic Engineer

Planning Planning and

Design Design

Construction Operation

Maintenance Research

Research

Geometric design deals with :

Features of the location alignments profile , cross-section , intersections , highway

type , aspect of control of access and system .

Reflects : Safety , driver desire , and driver comfort , and convenience .

Geometric design controls :

1- Primary Controls :

a) Highway system and classification .

b) Topography and environment .

c) Traffic .

2- Dependent Controls :

a)Design speed .


b)Design vehicle .

c)Level of Service ( L.O.S ) .

Classification of Highways :

1- By design ( freeway , arterial , … ) .

2- By root numbering .

3- By administrative ( government responsibility ) .

4- By functional classification .

Trip Steps :

1- Primary movement .

2- Transition .

3- Distribution .

4- Collection .

5- Access .

6- Termination .

Highway Classification :

A:

1- Principal Arterials .

2- Minors Arterials .

3- Major and Minor Collections .

4- Local Roads .

B:

1- Freeways .

2- Major Highways .

3- Local Roads .

Topography and Environment :

Factors Affect the Design of Highways :

1- Topography .

2- Physical features .

3- Land use encountered .

4- Geological conditions .

5- Soil conditions .

6- Ground water .

Traffic : Characteristics of Traffic :


1- Volume ( Design Hour Volume DHV ) .

2- Composition .

3- Speed .

Composition :

a) Size and weight .

b) Operating characteristics .

c) Slower and occupying more space .

Passenger Car Equivalent ( PCE ) : Factors :

1-

2- Sight distance .

Example :

1000 v.p.h

90 % Passenger Cars ( PC ) .

5 % Trucks . PCE = 5 PC .

5 % Buses . PCE = 3 PC .

Volume = ( 1000 x 0.9 x 1 ) + ( 1000 x 0.05 x 5 ) + ( 1000x 0.05 x 3 )

Volume = 1300 PC.p.h

Speed : Factors Affect Speed :

1- Capability of drivers and their vehicles .

2- The physical characteristics of the highway and its road side .

3- Weather .

4- Presence of other vehicles ( density ) .

5- Speed limitation :

- By law . - Traffic devices .

Speed : Rate of motion .

Operating Speed :

Is the highest overall speed at which a prevailing driver can on a given

highway under four able weather conditions , and under traffic conditions without

at any time exceeding the safe speed as determined by the design speed on a

section by section bases .

Factors Affect Operating Speed :

1- Physical characteristics of the highway .


2- Volume or density of the traffic .

3- Climate or weather conditions .

V \ C = 1 The speed will decreases .

Design Speed :

Is the maximum safe speed that can be maintained over specific section of the

highway when the conditions are so far that the designed features of the highway

govern .

Factors determining design speed :

1- Safety .

2- Mobility .

3- Efficiency .

Factors affecting design speed :

1- Characteristics of terrain .

2- Extend of man made features .

3- Economical considerations .

Advantages :

1- Increases safety and capacity .

2- Lower fuel consumption and operating cost .

3- More comfortable driving conditions .

4- Better provision for future growth .

Design Vehicle :

Selected motor vehicle with the weight , dimension , and operating characteristics

of which are used to establish highway design controls to accommodate vehicles

of detected type .

Categories : 1- Passenger Cars PC :

- Small cars .

- Pickups .

- Vans . 2- Trucks :

- Single Unit Truck SU .

- WB 40 , Semi Truck Combination ( Medium ) .

- WB 50 , Semi Trailer Combination ( Large ) .

Level of Service ( L.O.V ) :


Reflects :

1- Speed and travel time .

2- Traffic interruptions .

3- Freedom to movement .

4- Comfort , convenience , and safety .

5- Economy .

A F

Parameters of Level of Service :

1- Operating Speed .

2- Volume to Capacity Ration ( V / C ) .

Level of Service in Uninterrupted Flow : Depends on :

1- Profile grade .

2- Sequence and arrangement of entrances and exits .

3- Number and arrangement of lanes .

4- The quality of alignments as reflected by design speed .

Weaving Area .

Level of Service at Intersections :

Depends on :

1- The design of the intersection .

2- Their sequence and the type of control utilized .

R.T.O.R : Right Turn on Red .

Highway Types :

Elements of Design : 1- Sight Distance :

The length of the highway ahead visible to the driver :

a) The distance required for stopping on all of the highway .

b) The distance required for passing an overtaken vehicle , acceleration , only

in two – lanes highways .

c) The distance needed at complex locations .

d) The distance criteria for measuring these distances for use in designing . 2- Stopping Sight Distance ( SSD ) :

Is the sum of two distances :


a) The distance through by the vehicle from the instant the driver sights an

object necessary to stop to the instant the brakes are applied .

b) The distance required to stop the vehicle from the brakes application

begins. SSD = 1.47 vt+ v

2 /30 ( f + g )

Friction Factor :

1- Dry Conditions .

2- Wet Conditions .

- g : Grade 4 % .

- Reaction time = 1.57 sec if not given .

- G if straight = 0 .

a) Air pressure of tires .

b) Composition of tires .

c) Tire tread pattern .

d) Depth of treads .

e) Type of the conditions of the pavement surface .

f) Pressure of moisture , wind , snow , etc .

g) Braking system .

3- Decision Sight Distance ( DSD ) :

Is the distance required for the driver to detect an expected or otherwise difficulty

to perceive information source or a danger on the roadway environment that may

visually cluttered , recognized the hazard or its strip potential select an

appropriate, initiate and complete the required safety lane , and safe efficiency .

- Premaneuver Time :

Is the time required for the driver to process information relative to the hazard ,

and composed of :

a) Detecting or recognizing the hazard .

b) Deciding on proper maneuver an initiate required action ( 3.5 – 4.5 ) sec .

4- Passing Sight Distance ( PSD ) :

Assumptions :

a) The overtaken vehicle travels on uniform speed .

b) The passing vehicle has reduced speed and trails the overtaken vehicle as it

enters the passing section .

c) When the passing section is reached the driver requires a short period of

time to perceive passing section and to react start .


d) Passing is accomplished under what may be termed a dilate start and a

harried retermed in the face of traffic .

Horizontal and Vertical Alignments :

Safety : Stages of establishing a project :

1- Concept formulation .

2- Planning .

3- Preliminary design .

4- Engineering design .

5- Testing or protyped development .

6- Construction .

7- Operation .

Safety Envelope or Safety Project :


Goals :

1- Prevent death .

2- Prevent injuries .

3- Reducing accidents .

4-

Identification of Hazard :

Is any condition , device design , feature , or situation which can either : a)

contribute the occurrence of accident , b) contribute to the signally of an injuring

to a human being involved in an accident or c) both .


How to identify a hazard :

1- By inspection ( analysis ) investigation surveys .

2- By accident or incident analysis .

Factors Affect the Occurrence of Accidents :

1- Psychological attitude .

2- Experience .

3- Training .

4- Inadequate education .

5- Inadequate vision .

6- Inadequate reaction time .

7- Complication of driving task .

Methods for Improving Traffic Safety :

A- Reduction of Accidents Occurrence :

1- Provide designs that minimize the risk of driver error .

2- Proper signing and marking .

3- Highway design that avoid sudden change in geometry , good side in a

distance , smooth size .

4- Proper implementation of control to remove conflux .

5- Improve lighting .

B- Reducing the Severity of Accidents ( Forgiving Highway ) :

Enough space and time to recover from error and minimize the severity .

1- Grade rail .

2- Impact reducers .

3- Break away sign post .

4- Light stand .

C- Improve Crash Survivability :

D- Programmatic Safety Efforts :

1- Vehicle inspection programs .

2- National speed limit .

3- National 21-year drinking age .


4- National driving while intoxicated ( DWI ) programs .

5- National vehicle design standard .

E- Design Aspects of Safety :

1- Horizontal and vertical alignments .

2- Roadside design :

- Clear shoulders .

- Gentle side slope .

- Absence of solid objects .

- Sign posts or other objects must be protected by guardrail or breakaway

type .

3- Median barriers .

4- Gore area .

Accident Data Collection and Record System : 1- Identification of the locations at which unusually high number of accidents

occurs.

2- Detailed functional evaluation of high accident locations to determine the

contributing causes of accidents at the locations .

3- Development of general statistical measurements of various accident-

related factors to give insight into general trend , common causes , driven

profile , and similar information .

4- Development of procedures that allow the identification of hazards before

large number accidents occurs .

Traffic Control Devices ( TCD ) : Are all signs , signals , markings , and devices placed on , over , or next to a street

or highway by authority of public body or official having jurisdiction to regulate ,

warn , or guide traffic .

Traffic control devices help the driver by the following :

1- Warning of potential hazards .

2- Assigning the vehicle the right of the way at the intersections .

3- Providing guidance in navigation the chosen root .

4- Informing the driver of regulations such as speed limit , no parking , height

limit , weight limit , etc .

Manual Uniform on Traffic Control Devices ( MUTCD ) .

Conditions of effective traffic control devices :

1- Fulfill a need .

2- Command attention of drivers .


3- Respect of drivers .

4- Convey a clear simple message to drivers .

5- Give adequate time for proper response by drivers . To satisfy these conditions :

1- Design : Size , color , shape , reflectorization , and message .

2- Placement : Proper position to the situation .

3- Maintenance .

4- Uniformity or Consistency .

Signals : Types of Signals :

1- Regulatory : Stop yield , give notice to traffic laws , and regulation .

2- Warning : Call attention to the conditions that are potentially hazardous to

traffic operations .

3- Guide : Show route designations , destinations , directions , distances ,

services and information .

Three Principles Related to Good Practice on Roads :

1- Driver Expectancy :

- Experience .

- Type of the road .

2- Positive Guidance :

The driver can be give sufficient information when he needs it and in a form he

can best use it to safely avoid a hazard . ( e. g : Tapering which is a yellow colored

line at the edges of the road ) .

3- Consistency :

The sameness of the nature of the road from one section to another section .

Subtasks of Basic Driving Tasks :

1- Control :

Is the interaction between the driver and the vehicle ( steering wheel , accelerator ,

brakes , or the mechanism used in control ) .

2- Navigation :

Is the ability of the driver to plan and execute a trip from one point to another

using maps , ground marks , etc . 3- Guidance :

Is the ability of the driver to follow a safe path on the highway from the

information obtained directly from the highway traffic control devices .


Traffic Engineering : Is that phase of transportation engineering deals with the planning , geometric

design , and traffic operations of roads , streets , and highways , their network

terminals and the relationship with other modes of transportation .

Areas of Traffic Engineering :

1- Traffic studies .

2- Traffic planning .

3- Installation and maintenance of traffic control devices .

4- Traffic administration .

Importance of Traffic Engineering in Community Life : 1- Safety :

- Improve visibility .

- Proper use of traffic control devices .

- Proper placement of traffic control devices .

- Minimize complex maneuver at intersections .

2- Economic Factors :

- Faster .

- Increased employment opportunities .

- Use less gas .

- Safer roads mean cheaper insurance cost .

3- Environmental Aspects :

- Noise .

- Water and air pollution .

- Aesthetic .

- Ecological ( effects on animals and plants ) .

- Energy consumption .

Traffic Measures :

1- Uninterrupted Flow :

Exists on the facilities when there is no external causes fpr periodic interruption to

movement ( i.e highways ) .

2- Interrupted Flow :

Exists on all other types of facilities on which signals , stop sign , or other external

devices causes periodic interruption to traffic flow .

Classification :


1- Macroscopic Parameters :

Describes the traffic as a whole :

a) Volume .

b) Speed .

c) Density .

1 - Volume : The number of vehicles which pass a point on a highway or a given highway or

the direction of the highway during specified time interval which is conveniently

taken to be an hour ( vph , vphpl ) .

v.p.h.p.l : Vehicle Per Hour Per Lane .

Volume = 0 , when :

- There are no vehicles passing .

- There is a traffic load so that vehicles can not move .

Types of Volume :

1- Average Annual Daily Traffic ( AADT ) :

AADT = Total traffic within a year

365

2- Average Daily Traffic ( ADT ) :

ADT = Traffic within less than a year

Number of the days

3- Average Annual Weekdays Traffic ( AAWT ) :

AAWT = Total traffic within weekdays

260

4- Average Weekdays Traffic ( AWT ) :

AWT = Total traffic within weekdays for less than a year

Number of the weekdays

Directional Design Hour Volume ( DDHV ) :

DDHV = AADT x K x D


K= Traffic within peak

Total traffic annually

D = traffic to the peak direction

Total traffic

Rate of Flow :

Same as volume but in less than an hour , also described as in an hour .

Example :

Time Vehicles

8:00 – 8:15 100

8:15 – 8:30 200

8:30 – 8:45 300

8:45 – 9:00 400

Volume = 1000

400 x 4 = 1600 vph ( Peak rate of flow ) .

Peak Hour Factor ( PHF ) = Peak Hour Volume = 1000

Peak Rate of Flow 1600

PHF interrupted = Peak Hour Volume

4 x Peak 15 minutes

PHF uninterrupted = Peak Hour Volume

12x Peak 5 minutes

2 - Speed ( Rate of Motion ) : Expressed as a distance per unit time ( m.p.h , k.p.h , f.p.s , m.p.s ) .

1 m.p.h = 1.47 f.p.s

1 k.p.h = 0.278 m/sec


Traffic as a Whole :

1- Time Mean Speed ( TMS ) :

The average speed of all vehicles passing a point on a highway or a lane during

specified time interval .

TMS =

d : distance .

ti : time for each vehicle to complete the distance .

n : number of vehicles .

2- Space Mean Speed ( SMS ) :

The average speed of all vehicles occupying the given length of a highway or a

lane during specified time interval .

SMS =


3 – Density : Is the number of vehicles occupying a given length of a roadway, foreway or a

lane of a highway .

v.p.m : Vehicle Per Mile .

v.p.m.p.l : Vehicle Per Mile Per Lane .

Parameters Describe Density :

1- Spacing : Is the distance between two vehicles in traveling stream

measured from the front of the lead vehicle to the front of the

following vehicle ( in ft ) . ( ft \ veh ) .

2- Headway : is the time between the lead vehicle to pass a point and

the front of the following vehicle to pass the same point ( in seconds). (

sec \ veh ) .




Urban Transportation Planning ( UTP ) : Is a process that leads to decisions on transportation policies and programs . Its

objective is to develop information about the impacts of implementing alternative

courses of action involving transportation services such as new highways , bus

root changes , and parking restrictions .


Urban Transportation Planning is a Process of :

1- Understanding the type of decision that is needed to be made .

2- Assessing opportunities and limitations of future .

3- Identifying the shunt and long term consequences of alternative devices

disguard to take the advantages of these opportunities or spread to these

limitations .

4- Relating alternative decisions to the goals and the objectives established for

an urban area agency or firm .

5- Presenting these information to decision makers in readily , understandable

and useful form .

Characteristics and Measures of Person Travel in Urban Area :

Person Travel Characteristics :

1- Travel Demand :

Measured by :

- Number of trips .

- The amount of usage made of the transportation network .

Number of Trips :

Trip :

Is one way movement from the point where the trip begins to the point where the

trip ends .

Types of Trips : 1- Person Trips ( PT ) :

PT = R x n

R : Trip rate , n : Number of persons in the group .

2- Vehicle Trip .

Example :

Vehicle trips = 500 v.p.d .

Person trips = 500 x 2 = 1000 p.p.d . Two persons in each vehicle .

VT and PT are related by the vehicle occupancy .


Amount of travel = total trips made x their traveled distance .

= 1000 x 100 = 100 000 VMT .

VMT : Vehicle Mile Travel .

If the number of persons in each vehicle = 2

PMT = 2000 x 100 = 200 000 PMT .

PMT : Person Mile Travel .

Example :

Number of Vehicles Vehicle Occupancy Distance Traveled

(mile)

500 1.5 500

300 2.0 700

200 3.0 800

VMT = [ 500 x 500 ] + [ 300 x 700 ] + [ 200 x 800 ]

VMT = 620 000

PMT = [ 500 x 1.5 x 500 ] + [ 300 x 2 x 700 ] + [ 200 x 3 x 800 ]

PMT = 1 275 000

Example :

Occupancy Before ( % Vehicles ) After ( % Vehicles )

1 60 50

2 30 35


3 10 15

Distance traveled = 20 000 km .

Find percentage change in VkmT ( n = 1000 ) .

PkmT before :

1 x 0.6 x 1000 x 20 000 = 12 000 000

2 x 0.3 x 1000 x 20 000 = 12 000 000

3 x 0.1 x 1000 x 20 000 = 6 000 000

PkmT before = 30 000 000

PkmT after :

1 x 0.5 x V x 20 000 = 10 000 V

2 x 0.35 x V x 20 000 = 14 000 V

3 x 0.15 x V x 20 000 = 9000 V

PkmT after = 33 000 V

PkmT before = PkmT after

33 000 V = 30 000 000

V = 909 vehicle .

Basic Parameters of Travel Demand :

1- Its Purpose ( Why ? ) :

a- Home – Base Work ( HBW ) .

b- Home – Base Other ( HBO ) .

c- Non – Home Base ( NHB ) .


d- Internal – External Trip .

e- External – Internal Trip .

f- Through Trip .

Rules to Identify Trips :

1- Trips that either begin or end at the traveler’s home are produced at the

home end .

2- Trips that either begin or end at the traveler’s home are attracted to the non

– home end .

3- Trips that begin at a non – home location and end at another home location

are produced at the origin and attracted at the destination .

Factors affect the trip type :

a- Sex , or tender ( male or female ) .

b- Age .

c- Income and vehicle ownership .

2- Its Amount ( How much ? ) :

a- Size and density of urban area .

- Low density and higher vehicle ownership , higher trip rate .

- High density and low vehicle ownership , lower trip rate .

b- Place and type of residence .

c- Income and car ownership .

Size of Household :

5000 Person

5 Persons per family

500 family

-

5000

4 Persons per family

1250 family

3- Its Temporal Distribution ( When ? ) :


4- Its Modal Requirements ( How ? ) :

Transit , PC , walk , etc .

5- Its Geographical and Directional Distribution ( Where ? ) :

Travel Demand Forecasting ( TDF ) :

Quantify the land activity .

Travel Demand Forecasting ( TDF ) :

1- Micro Analysis Tool .

2- Sketch Tool .

3- Rational Method .


Four – step Procedure :

Predicts :

a- When people will live .

b- When businesses are located .

c- Intensity .

Trip Condition :

Forecasts the number of trips that will be made .

1 2 3

1 10 30 20

2 20 15 35


- Trips that begin from zone 1 and

end at zone 1 are 10 .

- The summation of all trips that

begin from zone 1 and end at all zones is 60 .

Trip distribution depends on :

The relative attractive and accessibilities of the zone .

Zone 1 is more attractive and more accessible than zone 2 .

Mode Usage :

Predicts two trips will be divided among the available modern travel . Trip

assignment predicts the routine that the trip will take .

Considerable Characteristics to Choose Transportation Means :

1- Characteristics of the trip maker .

2- Characteristics of the trip .

3- Characteristics of the transportation system .

Information Needed for Travel Demand Forecasting :

1- Studied area ( developed and undeveloped area ) .

2- Urban activation .

3- Transportation system .

4- Travel .

Contour Line :

- Future growth .

- Political restrictions .

- Causes area boundary .

- National boundary .

- Cross minimum .

Urban Activation :

Provides intensity and characteristics of activities in each zone .

Residential Area :

Population : 1200 .

Household : 400 .

Average income : 1200 JD .

3 30 56 74


Shopping Center :

Employed : 120 .

Parking :

Transportation System :

Describes the transportation system in terms of its geometry ( what is connected

with what ) , and its travel service ( two well points are connected ) .

Level of Service ( L.O.S ) :

Quantifies the ease with which these conditions are made , time and cost .

( Time and cost are travel impedance ) .

Travel Information :

Information on how , when , where and why people are currently traveling .

Public Transportation :

1- Low Capacity Modes :

a- Taxies :

- Longer waiting time .

- No parking problems .

- Higher out of pocket money . b- Dial – A ride – or Dial a Bus , Vans ( Minibuses ) :

- Lower cost service .

- More comfortable right .

- Slower than direct travel .

- Less personalized service .

- Service with a limited area only . c- Jitneys :

- High frequency service .

- Higher travel speed .

- Lower reliability , safety , and comfort .

2- Medium Capacity Modes :

a- Regular Buses ( Fixed Root and Fixed Schedule ) :

- Higher reliability .


- Lower cost per passenger .

- Less personal ride service .

- Less frequent service .

b- Express Buses :

- Higher speed .

- Higher firm .

- Move comfortably .

- Serve few points .

c- Trolley Buses :

- Higher righting quality .

- Ability to operate on

- Excellent in varmint feature .

d- Street Cars :

- Better vehicle performance .

- More comfortable .

- Higher line capacity .

3- High Capacity Modes :

a- Semi Rapid Transit ( SRT ) buses .

b- Light Rail Transit ( LRT ) .

c- Rapid Transit .

b and c are trains with :

- High construction cost .

- Large number of passengers .

- Low operation cost .

Aspects of Transit System Operations :

1- Headway ( h ) :


Is the time interval ( in minutes ) between two successive departure of transit

vehicles on a line .

2- Frequency of Service ( f ) :

The number of transit vehicles passing a point on the line during one hour .

3- Vehicle Capacity ( Cv ) :

Is the total number of passengers space on the vehicle . ( Cv =

number of seats + number of standers ) .

4- Passenger Volume ( P ) :

Is the number of passengers traveling on a line passing a fixed point during one

hour .

5- Design Hour Volume ( DHV ) :

Highest passenger volume for all sections along the line .

6- Line Capacity Afford ( C ) :

The total number of passengers space offer at a fixed point of transit line during

one hour .

C= f x Cv

7- Operating Time ( To ) :

Is the scheduled time interval between departure of a vehicle from one terminal

and its arrival at another terminal on a root in minutes .

8- Operating Speed ( Vo ) :

The average speed of transit vehicle including stopping time at stations.

9- Terminal Time ( tt ) :

Is the time of vehicles spent at a terminal or into line stop in excess on the interval

required for boarding and alighting .

10- Cycle Time ( T ) :

Is the total around trip time for a vehicle .

T = 2 ( To + tt ) .


11- Commercial Speed ( Vc ) :

Is the average speed of transit vehicle to complete around trip .

12- Fleet Size ( Nf ) :

The total number of vehicles where transit agency owns .

Nf = N + Nr + Nm

Nr : reserve .

Nm : maintained .

13- Load Factor ( α ) :

Is the ratio of the number of passengers in the vehicle to the vehicle capacity .

Bus Priority Measures : Public transport service less effective :

1- Land use changes have increased a less centrally oriented patterns of

travel .

2- The increasing availability of cars has decreased the demand for

public transport .

3- Traffic conjunction caused by increased car usage has interfered for

efficient operation of bus service .

Conditions of Effective Bus Service :

1- Concentration of bus operation .

2- High degree of bus and car conjunction .

3- Community will be able to support transportation .

Aims of Bus Priority Measures :

1- Provide good operating environment .

2- Save passengers travel time and cost .

3- Conserve energy .

4- Improving the environment .

Bus Priority Includes :

1- With – flow bus lane .

2- Contra – flow bus lane .

3- Bus – only streets .

4- Priority at traffic signals .


HOV : High Occupancy Vehicle .

Types of Bus Stop Locations :

1- Near side bus stop .

2- For side bus stop .

3- Mid block bus stop .

Rush Hour Cost :

- Spreading the peak ( staged work ) .

- Increasing schedule speed by :

a- Making the duration of stops as short as possible by letting passengers off

and on the bus quickly .

b- Making few stops as possible for passengers .

c- Making few stops as possible for traffic delay .

Transportation Engineering

Documents

b travel cost

travel time

b transportation mode

ease of travel

mode of transportation

b attraction

travel demands

functions of transportation