What shape is a standard stop sign in the US and many other countries?
AnswerOctagon
Stop signs use a distinctive red eight-sided shape so drivers can recognize them at a glance.
Vehicles · Facts & stats
Drive facts & stats
7 fact-checked facts about driving and cars, each with the reason behind it. 5 more are in today's round and join this page after it closes.
The basics
What does a car's odometer measure?
AnswerTotal distance traveled
The odometer records distance; the speedometer shows speed.
Going deeper
What are the four strokes of a four-stroke engine, in order?
AnswerIntake, compression, power, exhaust
The piston draws in fuel and air, compresses it, is pushed down by combustion, then pushes out exhaust.
What does a tachometer show?
AnswerEngine revolutions per minute
A tachometer displays how fast the engine's crankshaft is turning, in RPM.
Where was the world's first traffic light installed, in 1868?
AnswerLondon
A gas-lit semaphore signal was installed outside the Houses of Parliament in London in 1868.
Expert level
What does a car's differential allow?
AnswerWheels on the same axle to turn at different speeds
When cornering, the outer wheel travels farther than the inner one; the differential lets them spin at different speeds.
What does a catalytic converter do?
AnswerConverts harmful exhaust gases into less harmful ones
Catalysts such as platinum turn carbon monoxide, unburned fuel and nitrogen oxides into less harmful gases.
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