Q 01/05

In which US city did police sergeant Harry Jackson create the first stop sign in 1914?

A) Detroit

B) Chicago

C) Cleveland

D) Pittsburgh

Answer · why

A) Detroit

Detroit police sergeant Harry Jackson cut the corners off a square board in 1914 so drivers would know the shape at a glance, then painted STOP on it.

Q 02/05

In the 1920s US plan that ranked road sign shapes by danger, which shape marked the gravest hazard, railroad crossings?

A) An octagon

B) A circle

C) A diamond

D) A rectangle

Answer · why

B) A circle

A circle marked railroad crossings, judged the gravest danger, with the octagon next for stops, so drivers could read a sign by its outline when the l...

Q 03/05

Why did Colorado replace its Mile 420 marker on Interstate 70 with a sign reading 419.99?

A) The road was re-surveyed

B) Drivers found it unlucky

C) Thieves kept stealing it

D) A printing error stuck

Answer · why

C) Thieves kept stealing it

Thieves kept stealing it because 420 is slang for cannabis, so Colorado posted Mile 419.99 instead, and Idaho later swapped its own marker for 419.9.

Q 04/05

Why were US stop signs yellow, not red, until 1954?

A) Red meant railroads

B) Yellow was cheaper

C) Red meant fire

D) Red paint faded

Answer · why

D) Red paint faded

Red paint faded on exposure, largely why a 1920s plan put STOP on yellow; fade-resistant finishes let the manual turn it red in 1954.

Q 05/05

What shape is Japan's stop sign?

A) An inverted red triangle

B) A red octagon

C) A red circle with a white bar

D) A white diamond

Answer · why

A) An inverted red triangle

An inverted red triangle replaced a Western-style sign in 1963, just before the Tokyo Olympics, and the English word STOP joined the Japanese from 201...