58559土木工程专业英语鲁正电子课件-普及版-

Unit

9

Introduction

to

Traffic

Engineering9.1Introduction9.2

Traffic

Management

andControl9.1

IntroductionTraffic

can

be

defined

as

the

movement

of

pedestrians

and

goods

along

a

route,

and

inthe

21st

century

the

biggest

problem

and

challenge

forthe

traffic

engineer

is

oftentheimbalance

between

the

amount

oftraffic

and

the

capacity

of

the

route,

leading

tocongestion.

Traffic

congestion

is

not

a

new

phenomenon.

Roman

history

records

thatthe

streets

of

Rome

were

so

clogged

with

traffic

that

at

least

one

emperor

wasforcedto

issue

a

proclamation

threatening

the

death

penalty

to

those

whose

chariots

and

carts

blocked

the

way.More

recently

pictures

of

our

modern

cities

taken

at

the

turn

ofthe

century

show

streets

clogged

with

traffic.

The

dictionary

describes

’traffic’

as

thetransportation

of

goods,

coming

and

going

of

s oods

by

road,

rail,

air,etc.Often

in

common

usage

we

f et

this

wider

definition

andcolloquially

equate

theword

with

motorised

road

traffic,

to

the

exclusion

of

pedestrians

and

even

cyclists.Traffic

engineering

is

concerned

with

the

wider

definition

of

traffic.交通的定义congestion

拥挤；proclamation

公告；chariots

二轮战车；carts

二轮马车；colloquially

口语地；9.1

IntroductionThe

definition

remains

valid

today

but

there

hasclearly

been

achange

in

theemphasis

in

the

roleof

theengineer

inthe

time.

Inthe1970sthe

car

was

seenasthefuture

and

the

focus

was

very

much

‘predict

and

provide’.

Traffic

engineers

weretasked

with

increasing

the

capacity

of

the

highway

system

to modate

whatseemed

and

endless

growth

in

motor

traffic,

often

at

the

expense

of

other

roadusers.Road

capacity

improvements

were

often

achieved

at

the

expense

ofpedestrianfreedom

ofmovement,

pushing

pedestrians

tobridgesand

underpassesso

that

thesurface

could

be

given

over

to

the

car.

However,

it

is

now

generally,

but

by

no

meansuniversally

recognized

that

we

will

never

be

able

to modate

unconstrainedtravel

demand

by

car

and

so

increasingly

traffic

engineering

has e

focusedonsharing

space

and

ensuring

that

more

sustainable

forms

of

transport

such

as

walkingy

catered

for.andcycling

areadequa交通定义的变化were

tasked

with

受…；unconstrained

无约束的9.1

IntroductionTar

has

been

used

for

many

years

in

road

construction

both

as

a

binder

formacadam

andasasurface

dressinginitially

onwater-boundroads.Roadtar

istoday

specified

in

BS

761

by

the

following

definition:

‘tar

for

use

in

road

work

isprepared

entirely

from

crude

tars

producedwholly

or

substantially

as

aby-product

inthe

carbonisation

of

coal

at

above

600

°Cin

externally

heated

retortsor

cokeovens’.公路路面材料介绍Tar

柏油；binder

粘合剂；macadam

碎石；crude

粗糙的；天然的；carbonization

碳化作用；retorts

曲颈瓶；coke

ovens

炼焦炉9.1

IntroductionConcrete

pavements

are

constructed

in

a

variety

of

forms

by

several

differentconstruction

methods.

Theymay

bereinforced

orunreinforced;

ifreinforced

thesteel

may

take

the

form

of

individual

bars

or

welded

mesh.

The

slabs

may

containseveral

different

types

of

joint

or

they

may

be

unjointed

or

continuous.Construction

may

be

carried

out

bythe

conventional

side-form

processusing

aconcreting

train

with

many

differing

units,

or

one

of

several

forms

of

slip-formpaver

may

be

employed

operating

with

a

minimum

of

additional

equipment.混凝土路面施工welded

mesh

焊接网；slabs

板材；conventional

传统的；9.1

IntroductionThe

importance

ofadequate

drainage

was

realised

by

Roman

road

builders,

butafter

the

decline

of

theRoman

Empire

the

standard

ofhighway

constructioninEurope

declined

and

planned

drainage

became

almost

non-existent.

With

theadvent

of

industrialization,

increasing

attention

was

paid

to

the

removal

of

surfacewater

andthe

loweringof

the

water-table

beneath

the

pavement.

Inthe

UnitedKingdom

the

pioneer

road-buildingof ford

and

Macadam

laid

stress

on

theincorporation

of

a

camber

or

crown

intothe

road

so

that

surface

water

couldbequickly

removed.

Increasing

urbandevelopment

made

openditches

inappropriateand

led

to

the

increasing

use

of

road

gulleys

connected

to

road

sewers

asthemeans

of

removing

surface

water.

Improvements

in

the

quality

of

roadmaterialshave

resulted

in

impervious

pavements,

making

theproblem

ofsub-soil

usuallygreatest

in

the

cuttings,

wherecut-off

drainage

is

required.路面排水系统介绍industrialisation

工业化；camber

弧形；ditches

沟渠；gulleys

集水口；impervious

pavements

不透水路面；9.1

IntroductionA

site

investigation

is

an

essential step

in

the

design

of

anyhighway

onanew

location.

The

information

obtained

bythe

survey

assists

in

locating

thehighwaytoavoid

adverse

geological

conditions

andin

designingearthworks,pavement

thickness,

drainage

works

and

bridgefoundations.实地勘测adverse

geological

conditions

不良地质条件；earthworks

土方工程；9.1

IntroductionWith

the

drainage

works

completed

and

all

services

and

ducts

crossing

thecarriage-way

inplace,

the

formation

maybe

sealed

toprotect

the

subgrade

fromexcessive

moisture

changes.

This

is

because

a

cohesive

subgrade

which

hase

excessively

dry

due

to

evaporation

during

a

dry

construction

season

mayswell

with

subsequent

increases

in

moisture

content,

resulting

in

differentialmovement

of

the

pavement.

On

the

other

hand

a

subgrade

that

has

eexcessively

wet

is

difficult

to

compact

and

to

overlay

withsub-base

material.铺面施工formation

地层；duct

管道；seal

密封；subgrade路基；excessive

过度的；cohesive有粘着力的；evaporation

蒸发；swell

with膨胀，充满；9.1

IntroductionThe

twentieth

century

has

seen

a

considerable

improvement

in

the

materials

andconstructional

techniques

usedforhighwaypavements.

This

hasresulted

in

adramatic

increase

inthe

life

ofapavement

fromthe

periodwhen

anannualsurface

dressing

was

necessary

to

maintain

the

sh of

the

pavement

tothepresent

time

when

designlives

offromfive

to

twenty

yearsarecommon

forheavily

trafficked

highways.路面养护介绍dramatic

急剧的；trafficked

行车的；9.1

IntroductionEvery

trip

byavehicle

results

inaparking

act

at of

the

trip.

Theimportance

ofparking

can

perhapsbe

illustrated

bythe

fact

that,

o age,

a

carin

the

UK

is

parked

forabout

23

hours

a

day.

Thevehicle

may

be

parked

onthestreet

or

off-street

in

a

car/lorry/cycle

park,

or

in

a

private

garage.

How

vehiclesarrive

anddepart

fromthese

parking

places,

how

longthey

stay

andunderwhatcircumstances

define

vehicular

traffic

and

indeed

some

pedestrian

traffic

on

theroads

andhelp

to

determine

what

measures

arerequired

to

meet

ormanagethedemand.

Therefore,

it

isveryimportant

toobtain

an

objective

and

unbiasedunderstanding

ofthisactivity

byproperly

constructed

andconducted

surveys.停车情况 的必要性unbiased

公正的；9.1

IntroductionThe

estimation

of

travel

demand

is

a

fundamental

part

of

traffic

engineeringdesign

work.

The

key

questions

are

how

much

effort

needs

to

be

expended

inestimating

demand

and

what

method

should

be

adopted.

The

answers

depend

onthe

nature

of

the

design

issues.

For

example,

a

minor

traffic

management

designto

improve

road

safety

over

a

length

of

road

in

inner

London

where

traffic

flowshave

been

stable

for

many

years

will

requirelittle

more

than

a

survey

of

existingtraffic.

The

reverse

is

true

of

a

proposal

for

a

new

roadway

to

assist

regenerationin

an

old

urban

area

where

design

will

depend

on

estimating

the

new

traffic

likelyto

be

attracted

touse

the

newroad.出行需求估计little

more

than

仅仅是；regeneration

重建；9.1

IntroductionThe

term

capacity

when

referringto

ahighway

link

orjunction

isits

ability

tocarry, modate

or

handle

traffic

flow.

Traditionally,

capacity

has

beenexpressed

in

numbers

of

vehicles

or

passenger

car

units

(PCU).(Vehicles

vary

intheir

performance

and

the

amount

of

road

space

they

occupy.

The

basic

unit

is

thepassenger

carand

othervehicles

are

counted

as

their

PCU

equivalent,

e.g.a

busmight

be

3

PCUs

and dal

cycle

0.1

PCU.)In

recent

years

public

transportoperators

have

applied

pressuretoconsider

highwaysin

terms

oftheir

passenger-handling

capacity

andthusgive

agreater

emphasis

tothe

benefits

ofusinghighoccupancy

vehicles,

such

asbuses

ortrams.通行能力分析operators

经营者；occupancy

占用；9.1

IntroductionTraffic

signals

are

used

to

regulate

and

control s

between

opposingvehicular

or

pedestrian

traffic

movements.

Without

the

use

of

signals

at

somesites

the

major

flow

would

dominate

the

junction,

making

entries

from

theminorroad

impossible

or

very

dangerous.

At

other

sites

the

minor

road

mightinterferewith

the

flow

of

major

road

traffic

to

such

an

extent

that

excessive

congestionwould

occur.

Traffic

signals

cannot

only

improve

junction

capacity,

but

c

soimprove

road

safety.

The

traffic

engineer

will

need

to

know

how

best

to

provideparking,

and

howto

control

parking

facilities

both

on-street

and

off-street,

both

insurface

sites

and

structures.交通信号介绍regulate

调节；dominate

支配；interfere

干扰；9.2

Traffic

Management

and

ControlTraffic

management

arose

from

the

need

to

ise

the

capacity

ofexistinghighway

networks

within

finite

budgets

and,

therefore,

with

a

minimum

of

newconstruction.

Methods,

which

were

often

seen

as

a

'quick

fix',

required

innovativesolutions

and

new

technical

developments.

Many

of

the

techniques

devisedaffected

traditional

highway

engineering

and

launched

imaginative

and

cost-effective

junction

designs.

Introduction

of

signal-controlled

pedestrian

crossingsnot

only

improved

the

safety

of

pedestrians

onbusy

roadsbut

improved

thetraffic

capacity

of

roads

by

notallowing

pedestrians

to

dominate

thecrossingpoint.

More

recently

the

emphasis

has

moved

away

from

simple

capacityimprovements

to

accident

reduction,

demand

restraint,

public

transport

priority,environmental

improvement

and

restoring

the

ability

tomove

around

safely

andfreely

onfootandbypedal

cycle.交通管理和控制概述arosefrom

起因于；

ise

尽量增大；

quick

fix

权宜之计；restraint

抑制克制9.2

Traffic

Management

and

ControlVehicle

speeds

are

affected

by

many

factors

including

speed

limit,

horizontal

andvertical

alignment,

visibility,

highway

cross

section,

adjacent

land

use,

spacing

ofjunctions,

accesses,

pedestrian

crossingsand

maintenance

standards.

T

eralcondition

and

design

of

vehicles

and

driver

ability,

which

changes

over

timecanhave

a

significant

effect

on

vehicle

speeds.

It

is

usual

to

use

an

85th

percentilespeed

as

the

design

speed

(the

speed

below

which

85%

of

drivers

travel).

The85th

percentile

speed

is

determined

from

speed

surveys

using

a

radar

speedmeteror

automatic

traffic

counters

equipped

to

measure

speeds.车辆速度的确认crosssection

横断面；percentile

百分位的；9.2

Traffic

Management

and

Control

rsonal

injury

accident

(PIA)

isan

accident

involving

aninjury.

ThePIArefers

tothe

accident

asthe

event,

and

may

involve

several

vehicles

andseveralcasualties

( s

injured).

Theaccident

must

occur

inthe

public

highway(including

footways)

and e

knownto

the within

30

days

of

itsoccurrence.

Thevehicle

need

notbe

moving

andit

need

notbein

collision

withanything.

A

casualty

is rson

killed

or

injured

in

an

accident.

Casualties

aresubdivided

into

killed,

seriously

injured

and

slightly

injured.道路安全工程collision

碰撞；casualty

伤亡；9.2

Traffic

Management

and

ControlTraffic

calming

has

two

main

objectives:

the

reduction

in

numbers

of

alinjury

accidents

and

improvement

inthe

local

environment

forpeopleliving,working

or

visiting

the

area.

Traditional

traffic

management

uses

physicalmeasures

and

legislation

to

coerce,

and

mould

driver

behaviour

to

coax

highercapacities

out

of

the

highway

network,

with

improved

levels

of

safety.

Trafficcalming

nowusesanexpanded

repertoire

ofmeasures

andtechniques

tochangedriver's

perception

of

an

area.

Many

streets

portray

theimpression

that

theyarevehicular

traffic

routes

that

have

some

other

uses

of

lesser

importance,

such

asshop streets

or

for

residential

access.

Traffic

calming

cter

the

balanceorresidentialand

impress

upon

the

driver

that

the

street

is

primarily

forshopuse

and

that

vehicular

traffic

is

of

secondary

importance.交通稳静化legislation

；coerce

强制；mould

塑造；coax

哄骗；repertoire

剧目；perception

认知；portray描绘9.2

Traffic

Management

and

ControlPublic

transport

priority

hasto

be

seen

in

the

context

ofan

overall

urbantransportstrategy

with

objectives

which

include

not

only

improved

bus

(or

tram)

operationand

restraint

ofcar-borne

commuting

but

also

an

enhanced

environment

forresidents,

workers

and

visitors.

Measures

proposed

must

serve

all

these

objectivesand

yet

also

be

demonstrably

cost-effective

and

enforceable公共交通优先权strategy

；restraint

抑制，约束；car-borne

汽车运载的；enhanced

加强的；9.2

Traffic

Management

and

ControlMost

developments

require

planning

consent

from

the

local

planning

authority,that

is,

district

or

unitary

authority,

and

the

context

for

obtaining

consent

isdescribed

in

legislation

such

as

the

Townand

Country

Planning

Act

1990,

inernment

policy

guidance

andin

local

authority

plans.

There

are

afe