THC Science

This is a comparison of road signs in countries that speak majorly English, including major ones where it is an official language and widely understood (and as a lingua franca).

[[Botswana, Lesotho, Malawi, South Africa, Swaziland, Tanzania, Zambia, and Zimbabwe are all SADC members who drive on the left (except Angola) and use the SADC Road Traffic Signs Manual, and thus have identical road signs.

Differences between traffic signs in English speaking countries

	Australia	Canada	Hong Kong	Ireland	Jamaica	Liberia	Mauritius	NZ	Nigeria	Philippines	RSA	Sierra Leone	Singapore	UK	USA
Drives on...	Left	Right	Left	Left	Left	Right	Left	Left	Right	Right	Left	Right	Left	Left	Right
Typical typeface(s)

Differences in units

All countries, with the exception of Liberia, the United States, and the United Kingdom, use the metric system. Some countries mark this fact by using units on various signs.
- Ireland, and parts of Canada (British Columbia, parts of Ontario, and Yukon) list units (km/h) on their maximum speed limit signs. In Canada and Ireland, this is a reflection of (somewhat) recent transitions from Imperial to metric.
- Advisory speed limit signs in most countries list units, although New Zealand does not. The US lists units in mph.
- Height, weight, and width restrictions are almost always accompanied by units (tonnes or metres); in the US, the short ton is used with no distinction from metric tonnes.
- Signs in some parts of Canada near the US border often include both metric and Imperial units, to remind American drivers that they are entering metric countries. No such equivalent exists in the US.^[1]
The US was, at one time, planning a transition to the metric system. The Metric Conversion Act of 1975 started the process, but it was halted in 1982. Nevertheless, the MUTCD specifies metric versions of speed limit signs. Furthermore, Interstate 19 in Arizona is partially signed in metric.

Color differences

Warning signs

Most warning signs are diamond-shaped and yellow or red-bordered triangular warning signs; some warning signs may be fluorescent yellow-green in order to draw extra attention. There are a few exceptions to this:
- Pentagonal signs are used in school zones in the United States, Liberia, and many areas in Canada. In the Philippines, pentagonal signs are permanently used for pedestrian crossings.
Warning signs may be text-only.

Road works and construction

Most countries use orange or yellow diamond-shaped signs or yellow, orange or white red-bordered triangular warning signs for construction zones. Australia and the Philippines use rectangular signs that fit into temporary casings.

Regulatory signs

Prohibitory and restrictive signs are classified as regulatory signs.
Almost all prohibitory signs use a red circle with a slash. Restrictive signs typically use a red circle, as in Europe. Some may be seated on a rectangular white background.
- The original MUTCD prohibitory and restrictive signs were text-only (i.e. NO LEFT TURN).^[2] Some of these signs continue to be used in the US.
Yield signs can be blank or have text with the legend "YIELD" or "GIVE WAY" depending on which country it is.
The No Entry / Do Not Enter sign may or may not feature text. In Ireland, an upwards-pointing arrow contained within a slashed red circle is used instead. Some countries have those two signs separated.
- The Latin American-style do not proceed straight sign may take a different meaning in countries with standard No Entry signs. Typically, it indicates an intersection where traffic cannot continue straight ahead, but where cross-traffic may enter the street from the right (or left). Thus, it is distinguished from a No Entry (for all vehicles) sign.

Mandatory or permitted-action signs

The design of mandatory signs varies widely, since the MUTCD does not specify their use.^[3] Rather, the MUTCD's equivalent are classified as regulatory signs.
- Some countries use simple arrows with the text "ONLY" or its equivalent underneath. This is the US and Australian standard.
- Some countries use European-style white-on-blue circular signs. These are "Type A Mandatory Signs" as prescribed by the Vienna Convention.
- Some Latin American countries use red-bordered circular signs, in the same style as regulatory signs. These are "Type B Mandatory Signs" as prescribed by the Vienna Convention. In cases relating to particular types of vehicle traffic (e.g. buses), these signs are identical to some European prohibitory signs.^[a]
- Canada uses a unique style of mandatory sign that features a green circle.

Warning

	Australia	Canada	Hong Kong	NZ	Philippines	Singapore	USA
Stop ahead		File:Canada - stop ahead.svg	?
Yield / Give Way ahead			?
Traffic signals ahead
Roundabout ahead
Two-way traffic ahead	File:Australia W4-11.svg				?
Uncontrolled railroad crossing ahead
Level railroad crossing with barriers ahead
Tram / streetcar crossing
Railroad crossbuck
Level crossing (multiple tracks)
Crossroads ahead
Junction with a side road ahead
Traffic merges ahead
Added lane
Divided highway ahead
Divided highway ends
Lane ends ahead
Road narrows ahead
Narrow bridge ahead
Dangerous crosswinds
Low-flying aircraft
Steep hill downwards
Steep hill upwards
Uneven surface
Bump in road ahead
Dip in road
Speed hump
Slippery road surface
Loose road surface
Pavement ends
Gentle curve ahead
Sharp curve ahead
Double gentle curve ahead
Double sharp curve ahead
Series of curves ahead
Hairpin curve ahead
School zone
Children / playground ahead	File:Australia W8-13 (fluorescent).svg
Pedestrian crossing ahead
Pedestrians on road ahead
Cyclists crossing
Falling rocks or debris
Opening or swing bridge	File:Australia W5-2.svg		Not used	Not used		Not used
Emergency vehicles
Farm vehicles
Domestic animals
Wild animals
Equestrians
Tunnel ahead			Not used			Not used	Not used^[b]
Height restriction ahead
Width restriction ahead
Length restriction ahead
Weight restriction ahead
Roadworks ^[c]

Regulatory

	Australia	Canada	Hong Kong	SADC
Stop
Yield / Give Way		File:Canada - yield sign.svg
Yield to oncoming traffic			?
No entry
Road closed/Vehicles prohibited	or			?
No left turn
No right turn
No U-turn
No overtaking
No motor vehicles
No motorcycles
No bicycles
No pedestrians
No heavy goods vehicles
No vehicles carrying dangerous goods
No vehicles carrying explosives
Minimum safe following distance between vehicles
Maximum speed limit
Minimum speed limit
Speed restriction ends
Maximum height
Maximum width
Maximum length
Maximum weight
Maximum weight per axle
No parking
No stopping

Mandatory or permitted actions

	Australia	Canada	Hong Kong	Ireland	Jamaica	Liberia	Mauritius	NZ	Nigeria	Philippines	SADC	Sierra Leone	Singapore	UK	USA
Proceed straight (no turns)
Turn right
Turn right ahead
Proceed straight or turn right
Keep right (or left)
Pass on either side
Roundabout
Overtaking permitted ^[d]
Shared use path
Pedestrians only
Bicycles only
Transit only

Other (indication)

	Australia	Canada	Hong Kong	Ireland	Jamaica	Liberia	Mauritius	NZ	Nigeria	Philippines	SADC	Sierra Leone	Singapore	UK	USA
One-way street
Two-way traffic
Pedestrian crossing
Dead end
Escape lane
Tunnel
Parking zone
Hospital
Bus stop
Train station
Airport
Freeway begins
Freeway ends
Customs post
National highway shield(s)

Notes

^ Compare Bicycles Only (Ciclovia) sign in Brazil: with No Bicycles (Verbot für Radfahrer) sign in Germany:
^ No equivalent sign in the national MUTCD. Individual state MUTCDs may include equivalent.
^ Temporary use only.
^ In many jurisdictions, "Overtaking Permitted" is indicated solely through a change in road markings, e.g. a solid center line changing to a dashed center line. In such jurisdictions, signs in this category are only posted in locations where a change in road markings is deemed insufficient notice for drivers. This is in contrast to "No Overtaking" signs, which are almost always posted alongside changes in road markings to indicate the end of an overtaking zone.

References

[regu-4] Compare Bicycles Only (Ciclovia) sign in Brazil: with No Bicycles (Verbot für Radfahrer) sign in Germany:

[noUSA-5] No equivalent sign in the national MUTCD. Individual state MUTCDs may include equivalent.

[temp-6] Temporary use only.

[nopass-7] In many jurisdictions, "Overtaking Permitted" is indicated solely through a change in road markings, e.g. a solid center line changing to a dashed center line. In such jurisdictions, signs in this category are only posted in locations where a change in road markings is deemed insufficient notice for drivers. This is in contrast to "No Overtaking" signs, which are almost always posted alongside changes in road markings to indicate the end of an overtaking zone.

[bc-1] British Columbia Manual of Standard Traffic Signs & Pavement Markings

[mutcdhist-2] MUTCD History

[mutcd-3] Manual on Uniform Traffic Control Devices, 2009 Edition

[1]

[2]

[3]

[a]

[b]

[c]

[d]