I couldn't find a reference to the minimum duration of yellow lights for traffic control signals in New York City's Administrative Code. It may be arguable that it must be a minium of 3 seconds and up to 6 seconds, depending upon the street and speed limight.
I did find an interesting reference to the
US Federal Highway Administration (FHA) Manual on Uniform Traffic Control Devices for Streets and Highways
- The purpose of the MUTCD is to establish uniform national criteria for the use of traffic control devices thatmeet the needs and expectancy of road users on all streets, highways, pedestrian and bicycle facilities, and siteroadways open to public travel.
- Section 1B.03 Compliance of Devices
Standard: 01 The U.S. Secretary of Transportation, under authority granted by the Highway Safety Act of 1966, decreed that traffic control devices on all streets and highways open to public travel in accordance with 23 U.S.C. 109(d) and 402(a) in each State shall be in substantial conformance with the Standards issued or endorsed by the FHWA.
Support: 02 23 CFR 655.603 also requires traffic control devices on all streets, highways, bikeways, and site roadways open to public travel in each State be in substantial conformance with standards issued or endorsed by the Federal Highway Administrator
- Section 1D.01: This Manual contains the basic principles that govern the design and use of traffic control devices for allstreets, highways, bikeways, and site roadways open to public travel (see definition in Section 1C.02) regardlessof type or class or the public agency, official, or owner having jurisdiction. The text of this Manual specifies therestriction on the use of a device if it is intended for limited application or for a specific system. It is important thatthese principles be given primary consideration in the selection and application of each device.
It seems like the FHA sets the standards and could set a minimum threshold for safety and is applicable to all streets in the US. Applicable section is below.
Section 4F.17 Yellow Change and Red Clearance Intervals
Support:01 The exclusive function of the yellow change interval is to warn traffic approaching a signalized locationthat their permission to proceed is being terminated after which they will be directed to stop, or in the case of aprotected/permissive turning movement that their protected movement is being terminated after which they willneed to perform their turn in a permissive manner
Guidance:
A yellow change interval should have a minimum duration of 3 seconds, and a maximum duration of 6 seconds. The longer intervals should be reserved for use on approaches with higher speeds. Except when clearing a one-lane, two-way facility (see Section 4O.02) or when clearing an exceptionally wide intersection, a red clearance interval should have a duration not exceeding 6 seconds.
A
duration of 3-6 seconds is recommended per a scientific study and according to the MUTCD. According to the
Manual on Uniform on Uniform Traffic Control Devices (MUTCD) the duration of a yellow light should be 3 to 6 seconds, as per below:
Section 4D.10 Yellow Change and Red Clearance Intervals
Standard:
A yellow signal indication shall be displayed following every CIRCULAR GREEN or GREEN ARROW signal indication.
The exclusive function of the yellow change interval shall be to warn traffic of an impending change in the right-of-way assignment.
The duration of a yellow change interval shall be predetermined.
Guidance:
A yellow change interval should have a duration of approximately 3 to 6 seconds. The longer intervals should be reserved for use on approaches with higher speeds.
Option:
The yellow change interval may be followed by a red clearance interval to provide additional time before conflicting traffic movements, including pedestrians, are released.
Standard:
The duration of a red clearance interval shall be predetermined.
Guidance:
A red clearance interval should have a duration not exceeding 6 seconds.
So it seems normal.
