homework encyclopedia

FIND OUT MORE. Engines 198–199

Congestion occurs when too many vehicles use

the same route at the same time, and traffic

slows or comes to a halt. One solution is to

build more roads, but some people argue

that the number of vehicles grows to fill

the roads available. An alternative is to

encourage people to use public transport.

HOW CAN ROAD SAFETY BE IMPROVED?

Driving too fast is a major cause of accidents. Speed

increases the severity of accidents. Nine out of ten

collisions with a pedestrian at 64 km/h (40 mph) are

fatal, but less than one in ten are fatal at 32 km/h

(20 mph). Speed bumps and traffic islands help to

keep speeds down. Radar speed traps and roadside

cameras catch speeding vehicles, encouraging drivers

to obey speed limits. Electronic signs on motorways

warn drivers to slow down in fog or snow.

Scientists are always looking for ways to improve safety on

the roads so that fewer people are hurt or killed in accidents.

Millions of people are injured each year in road crashes around

the world, but many more injuries are not reported.

WHY IS PUBLIC TRANSPORT IMPORTANT?

Public transport is more efficient and less polluting

than private cars. Underground rail can transport two

million people in and out of a city each day – two

million cars can block the roads. City planners also

encourage the public to use trams, bicycles, buses,

light railways, and ferries to reduce congestion.

WHAT IS GRIDLOCK?

The streets in many modern cities are

planned on a grid. At busy times traffic

may halt as traffic jams form at junctions.

This is called gridlock. Gridlock may be avoided

by synchronizing traffic signals from one junction

to the next, and by introducing one-way systems.

HOW IS A CONTAINER SHIP LOADED?

Container ships are loaded at special container ports.

The containers are easily transferred from road, to rail,

and to ship because each container is a standard size,

2.5 m by 2.5 m by 12 m (8 ft by 8 ft by 40 ft). They

stack together like bricks. The largest container ship

can carry 4,000 containers.

When goods are being transported they are called freight. Almost

everything you purchase – clothes, electronics, food, and books –

has been brought to the store from elsewhere.

1 TRAFFIC JAM

Managing traffic flow at peak periods and dealing with

incidents, such as crashes, are challenging problems for transport

planners. Engineers are developing ways to avoid jams – charging road

tolls to discourage drivers, introducing in-car navigation systems to

warn drivers of jams ahead, and installing synchronized traffic signals.

2 CRASH-TEST DUMMIES

New car models are crash-tested

in laboratories before they go

into production. Dummies in the

car show what happens to

passengers in a crash. The impact

forces in the crash are monitored

with sensors inside the dummies

and by high-speed videos.

ROAD SAFETY

CONGESTION

FREIGHT

4 LOADING CONTAINERS

A huge crane called a derrick

loads containers onto the ship.

The crew are careful that the ship

doesn’t tilt during loading. They

chalk numbers on the floor of the

ship so they know where to place

the different containers.

3200 BCE Wheels

3000 BCE Sailing ships

1803 Steam train

1807 Steamboat

1839 Bicycle

1885 Car

1903 Aeroplane

1947 Supersonic

flight

1952 Commercial

passenger flight

TRANSPORT FIRSTS