One thing I noticed on a read-through tonight, looking for something else, is that the MUTCD now allows 4 in./100mm lenses to be used on supplemental nearside bicycle signals. I think this is the first time in years a new allowed lens size has been added to the MUTCD, previously only 8 in./200mm and 12 in./300mm lenses were allowed for traffic signals (while pedestrian signals could only use 12 inch/300mm or 16 inch/~400mm square lenses). Presumably this brings
the 4 inch SWARCO heads that Portland, OR, had been using as of the past few years into compliance as a result.
Conekicker wrote: ↑Sun Jan 07, 2024 18:35
jervi wrote: ↑Sun Jan 07, 2024 01:04
It would be interesting (and time consuming) to directly compare TSM / DMRB with MUTCD, and other countries' standards
All of North and South America follows US signing to a decent degree, Spanish/Portuguese wording on certain signs excepted of course. The main difference is speed limit signing, where roundels tend to be used outside of the USA.
The closest similarity with US/UK signing is the STOP sign of course.
Traffic signals are probably going to be one of the bigger differences between the MUTCD and TSM/DMRB. Some of the bigger differences would be the standard placement of the primary signal heads, the use of red and yellow arrows (and u-turn arrows) over here, and that our pedestrian signals use an upright hand for the "Don't Walk" indication on pedestrian signals while y'all (and most other countries) use a standing man. The pedestrian signals over here are also required to use Portland Orange for the "Don't Walk" and white for the "Walk" indications, while y'all (and many other countries) use red and green for the pedestrian signals.
Another key difference is also the standard lens sizes. As I understand it, over there, y'all are only allowed to use round 8 in./200mm lenses on traffic and pedestrian signals, save for the box signs and 4 in./100mm low level cycle signals. Round 12 in./300mm were only allowed for special lenses such as pedestrian, cycle, and arrow indications during the Mellor era. Over here in the US, round 12 in./300mm lenses are the standard,
barring a handful of exceptions listed in Chapter 4, Section 4E.02 of the MUTCD, and all arrow indications must be 12 in./300mm as well. Pedestrian signals must use square 12 in./300mm or 16 in./~400mm lenses as well. And of course, as mentioned above, the 4 in./100mm bike signals now being allowed for installation.
Chapter 4, Section 4E.02 of the MUTCD: Size of Vehicular Signal Indications wrote:
Standard:
01 There shall be three nominal diameter sizes for vehicular signal indications: 4 inches, 8 inches,
and 12 inches.
02 Four-inch signal indications shall only be used for bicycle signal faces per Section 4H.07.
03 Twelve-inch signal indications shall be used for all arrow signal indications.
04 Except as provided in Paragraph 5 of this Section, 12-inch signal indications shall be used for all
circular signal indications in all new signal faces.
Option:
05 Eight-inch circular signal indications may be used in new signal faces only for:
A. The green or flashing yellow signal indications in an emergency-vehicle traffic control signal
(see Section 4M.02);
B. The circular indications in signal faces controlling the approach to the downstream location where two
adjacent signalized locations are close to each other and it is impractical because of factors such as high
approach speeds, horizontal or vertical curves, or other geometric factors to install visibility-limited signal
faces for the downstream approach;
C. The circular indications in a signal face that is located less than 120 feet from the stop line on a roadway
with a posted or statutory speed limit or operating speed of 30 mph or less;
D. The circular indications in a supplemental near-side signal face;
E. The circular indications in a supplemental signal face installed for the sole purpose of controlling
pedestrian movements rather than vehicular movements; and
F. The circular indications in a flashing beacon (see Chapter 4S).
06 Different sizes of signal indications may be used in the same signal face or signal head, provided that the
signal face or signal head complies with the requirements contained in Paragraphs 3 through 5 of this Section.
Probably busy documenting grade crossings in the southeastern United States.
(They/Them)