The Federal Highway Administration is taking comments on proposed amendments to the Manual on Uniform Traffic Control Devices, the book that dictates how federal, state, territorial, and local officials sign and mark streets and highways in the United States. The batch of proposed changes is pretty lengthy this time around, including new standards on consistent signing for toll roads, new recommendations on signs and pavement markings for roundabouts, and quite a few more pictographic signs replacing text legends borrowed from Canada and Mexico, including graphical “no passing,” “falling rocks,” and “no straight through” signs.

Other changes of interest, to me at least:

• States and territories that currently use sequential exit numbers will be required to adopt distance-based (“reference location”) exit numbering.
• New traffic signal standards for “protected/permissive” left turn signals that will apply to new installations only, including provisions for flashing red and yellow arrows.
• Adoption of special warning signs for motorcyclists and a symbol for a hypothetical nationally-interoperable electronic toll collection system.
• New “hybrid” signal types for usually-dark situations such as pedestrian crossings and emergency vehicle crossings.
• A requirement that all speed limit drops of 10 mph or more include a new-style “speed limit ahead” sign (this last one is similar to a suggestion I made in the last round of changes).