Chapter 4A. General¶

§4A.01 Types¶

Support

01. The following types and uses of highway traffic signals are discussed in Part 4: traffic control signals; bicycle signal faces; pedestrian signal heads; hybrid beacons; rectangular rapid flashing beacons; emergency-vehicle traffic control signals; traffic control signals for one-lane, two-way facilities; traffic control signals for freeway entrance ramps; movable bridge traffic signals; toll plaza traffic signals; flashing beacons; lane-use control signals; and inroadway warning lights.

§4A.02 Meanings of Signal Indications¶

Support

01. The “Michigan Vehicle Code” (see Section 1A.06) is the primary source for the standards for the meanings of vehicular signal indications to both vehicle operators and pedestrians as provided in Sections 4A.03 and 4A.04, and the standards for the meanings of separate pedestrian signal head indications as provided in Section 4A.06. The "Uniform Vehicle Code" is the primary source for the standards for the meanings of separate bicycle signal face indications as provided in Section 4A.05.

02. The physical area that is defined as being “within the intersection” is dependent upon the conditions that are described in the definition of an intersection in Section 1C.02.

§4A.03 Meanings of Steady Vehicular Signal Indications¶

Support

00. Sections 257.612(1) and 257.613(1) of the “Michigan Vehicle Code” provide meanings to steady vehicular signal indications for vehicle operators and for pedestrians, respectively. Paragraph 01 of this Section has been modified to reflect the “Michigan Vehicle Code.”

Standard

01. The following meanings shall be given to steady highway traffic signal indications for vehicles and pedestrians:

A. Steady green signal indications shall have the following meanings:
- 1. Vehicular traffic facing a CIRCULAR GREEN signal indication may proceed straight through or turn right or left unless a sign at that place prohibits either turn. Such vehicular traffic, including vehicles turning right or left, shall yield the right-of-way to other vehicles and to pedestrians and bicyclists lawfully within the intersection or an adjacent crosswalk at the time the signal is exhibited.
- 2. Vehicular traffic facing a GREEN ARROW signal indication, shown alone or in combination with another signal indication, may cautiously enter the intersection only to make the movement indicated by the arrow, or other movement permitted by other signal indications shown at the same time. The vehicular traffic shall yield the right-of-way to pedestrians and bicyclists lawfully within an adjacent crosswalk and to other traffic lawfully using the intersection.
- 3. Pedestrians facing a green signal indication, unless otherwise directed by a pedestrian signal indication or other traffic control device, may proceed across the roadway within a marked or unmarked crosswalk.
B. Steady yellow signal indications shall have the following meanings:
- 1. Vehicular traffic facing a steady yellow signal indication shall stop before entering the nearest crosswalk at the intersection or at a limit line when marked, but if the stop cannot be made in safety, a vehicle may be driven cautiously through the intersection.
- 2. A YELLOW ARROW indication has the same meaning as a CIRCULAR YELLOW indication, except that it applies only to vehicle operators intending to make the movement indicated by the arrow.
- 3. Pedestrians facing a steady CIRCULAR YELLOW or YELLOW ARROW signal indication, unless otherwise directed by a pedestrian signal indication or other traffic control device, are advised that there is insufficient time to cross the roadway and a pedestrian then starting to cross shall yield the right of way to all vehicles.
C. Steady red signal indications shall have the following meanings:
- 1. Vehicular traffic facing a steady red signal indication, unless entering the intersection to make another movement permitted by another signal indication, shall stop before entering the crosswalk on the near side of the intersection or at a limit line when marked or, if there is no crosswalk or limit line, before entering the intersection and shall remain standing until a green indication is shown, except as provided below. Vehicular traffic facing a steady red signal, after stopping before entering the crosswalk on the near side of the intersection or at a limit line when marked or, if there is no crosswalk or limit line, before entering the intersection, may make a right turn from a 1-way or 2-way street into a 2-way street or into a 1-way street carrying traffic in the direction of the right turn or may make a left turn from a 1-way or 2-way street into a 1-way roadway carrying traffic in the direction of the left turn, unless prohibited by sign, signal, marking, light, or other traffic control device. The vehicular traffic shall yield the right of way to pedestrians and bicyclists lawfully within an adjacent crosswalk and to other traffic lawfully using the intersection.
- 2. A RED ARROW indication has the same meaning as a CIRCULAR RED indication, except that it applies only to vehicle operators intending to make the movement indicated by the arrow.
- 3. Unless otherwise directed by a pedestrian signal indication or other traffic control device, pedestrians facing a steady CIRCULAR RED or steady RED ARROW signal indication shall not enter the highway unless they can do so safely and without interfering with vehicular traffic.

§4A.04 Meanings of Flashing Vehicular Signal Indications¶

Support

00. Section 257.614(1) of the “Michigan Vehicle Code” provides meanings to flashing traffic signal indications for vehicular traffic. Paragraph 01 of this Section has been modified to reflect the “Michigan Vehicle Code.”

Standard

01. The following meanings shall be given to flashing highway traffic signal indications for vehicles:

A. A flashing green signal indication has no meaning and shall not be used.
B. Flashing yellow signal indications shall have the following meanings:
- 1. When a yellow lens is illuminated with rapid intermittent flashes, drivers of vehicles may proceed through the intersection or past the signal only with caution.
- 2. A YELLOW ARROW indication has the same meaning as a CIRCULAR YELLOW indication, except that it applies only to vehicle operators intending to make the movement indicated by the arrow.
C. Flashing red signal indications shall have the following meanings:
- 1. When a red lens is illuminated by rapid intermittent flashes, drivers of vehicles shall stop before entering the nearest crosswalk at an intersection or at a limit line when marked and the right to proceed shall be subject to the rules applicable after making a stop at a stop sign.
- 2. A RED ARROW indication has the same meaning as a CIRCULAR RED indication, except that it applies only to vehicle operators intending to make the movement indicated by the arrow.

§4A.05 Meanings of Bicycle Symbol Signal Indications¶

Support

00. The “Michigan Vehicle Code” does not provide meanings for bicycle symbol signal indications for bicyclists. The “Uniform Vehicle Code” is the primary source for the standards for the meanings of separate bicycle signal face indications as provided in this Section.

Standard

01. The following meanings shall be given to bicycle symbol signal indications for bicyclists:

A. Bicyclists facing a steady GREEN BICYCLE signal indication are permitted to enter the intersection only to make the movement indicated by the lane-use arrow(s) displayed on the Bicycle Signal sign (see Section 9B.22) that is located immediately adjacent to the signal face, Bicyclists proceeding into the intersection during the display of the steady GREEN BICYCLE signal indication shall yield the right-of-way to:
- 1. Pedestrians lawfully within an associated crosswalk, and
- 2. Other vehicles lawfully within the intersection. 4A.04
B. Bicyclists facing a steady YELLOW BICYCLE signal indication are thereby warned that the related green movement is being terminated and that a steady RED BICYCLE signal indication will be displayed immediately thereafter when bicyclists shall not enter the intersection. The rules set forth concerning bicycle operation under the movement being terminated shall continue to apply while the steady YELLOW BICYCLE signal indication is displayed.
C. Bicyclists facing a steady RED BICYCLE signal indication shall not enter the intersection to make the movement indicated by the lane-use arrow(s) displayed on the Bicycle Signal sign (see Section 9B.22) that is located immediately adjacent to the signal face and, unless entering the intersection to make another movement permitted by another bicycle symbol signal indication, shall stop at a clearly marked stop line; but if there is no stop line, before entering the crosswalk on the near side of the intersection; or if there is no crosswalk, then before entering the intersection; and shall remain stopped until a GREEN BICYCLE signal indication permitting the movement indicated by such RED BICYCLE signal indication is displayed. Except when a traffic control device is in place prohibiting a turn on red, bicyclists facing a steady RED BICYCLE signal indication are permitted to enter the intersection to turn right if there are no approach lanes for motor vehicle traffic to their right. The right to proceed with the turn shall be subject to the rules applicable after making a stop at a STOP sign.
D. A flashing GREEN BICYCLE signal indication has no meaning and shall not be used.
E. A flashing YELLOW BICYCLE signal indication has no meaning and shall not be used.
F. Bicyclists facing a flashing RED BICYCLE signal indication shall stop at a clearly marked stop line; but if there is no stop line, before entering the crosswalk on the near side of the intersection; or if there is no crosswalk, at the point nearest the intersecting roadway where the bicyclist has a view of approaching traffic on the intersecting roadway before entering the intersection. The right to proceed in the direction indicated by the lane-use arrow(s) displayed on the Bicycle Signal sign (see Section 9B.22) that is located immediately adjacent to the signal face shall be subject to the rules applicable after making a stop at a STOP sign.

§4A.06 Meanings of Pedestrian Signal Indications¶

Support

Section 257.613(2) of the “Michigan Vehicle Code” provides meanings to pedestrian signal indications. Paragraph 01 of this Section has been modified to reflect the “Michigan Vehicle Code.”

Standard

01. Pedestrian signal indications shall have the following meanings:

A. A flashing WALKING PERSON (symbolizing WALK) signal indication has no meaning and shall not be used.
B. Pedestrians facing a steady WALKING PERSON (symbolizing WALK) signal indication may proceed across the highway in the direction of the signal and shall be given the right of way by the drivers of all vehicles.
C. Pedestrians facing a steady or flashing UPRAISED HAND (symbolizing DONT WALK) signal indication shall not start to cross the highway in the direction of the signals, but a pedestrian who has partially completed crossing on the walk interval of the signal shall proceed to a sidewalk or safety island while the don’t walk interval of the signal is showing.

§4A.07 Lateral Offset of Signal Supports and Cabinets¶

Guidance

The following items should be considered when placing signal supports and cabinets:

A. Reference should be made to the “Roadside Design Guide,” 4th Edition, 2011, AASHTO, and to the U.S. Department of Justice 2010 ADA Standards for Accessible Design, September 15, 2010, 28 CFR 35 and 36, Americans with Disabilities Act of 1990.
B. Signal supports should be placed as far as practicable from the edge of the traveled way without adversely affecting the visibility of the signal indications.
C. Where supports cannot be located based on the recommended AASHTO clearances, consideration should be given to the use of appropriate safety devices.
D. No part of a concrete foundation for a signal support should extend more than 4 inches above the ground level at any point. This limitation does not apply to the concrete foundation for a rigid support.
E. In order to minimize hindrance to the passage of persons with physical disabilities, a signal support or controller cabinet should not obstruct the sidewalk, or access from the sidewalk to the crosswalk.
F. Controller cabinets should be located as far as practicable from the edge of the roadway.
G. On medians, the minimum clearances provided in Items A through E for signal supports should be obtained, if practicable.

§4A.08 Use of Signs at Signalized Locations¶

Support

01. Traffic signal signs are sometimes used at highway traffic signal locations to instruct or guide pedestrians, bicyclists, or motorists. Among the signs typically used at or on the approaches to signalized locations are movement prohibition signs (see Section 2B.26), lane-control signs (see Sections 2B.27 through 2B.29), pedestrian crossing signs (see Section 2B.57), pedestrian and bicycle actuation signs (see Section 2B.58), traffic signal signs (see Sections 2B.59 and 2C.44), No Turn on Red signs (see Section 2B.60), Signal Ahead warning signs (see Section 2C.35), Street Name signs (see Section 2D.45), and Advance Street Name signs (see Section 2D.46).

Guidance

02. Regulatory, warning, and guide signs should be used at highway traffic signal locations as provided in Part 2 and as specifically provided elsewhere in Part 4.

Support

03. Section 2B.27 contains information regarding the use of overhead lane-control signs on signalized approaches where lane drops, multiple-lane turns involving combined through-and-turn lanes, or other lane-use regulations that would be unexpected by unfamiliar road users are present.

Guidance

04. If used, illuminated traffic signal signs should be designed and mounted in such a manner as to avoid glare and reflections that seriously detract from the signal indications. Highway traffic signal faces should be given dominant position and brightness to maximize their priority in the overall display.

Standard

05. The minimum vertical clearance and horizontal offset of the total assembly of traffic signal signs (see Section 2B.59) shall comply with the provisions of Sections 4D.09 and 4D.10.

06. STOP signs shall not be used in conjunction with any highway traffic signal operation, except in either of the following cases:

A. If the signal indication for an approach is a flashing red at all times, or
B. If a minor street or driveway is located within or adjacent to an area controlled by a traffic control signal, but does not require separate traffic signal control because an extremely low potential for conflict exists.

§4A.09 Use of Pavement Markings at Signalized Locations¶

Support

Pavement markings that clearly communicate the operational plan of an intersection to road users play an important role in the effective operation of highway traffic signals. By designating the number of lanes, the use of each lane, the length of additional lanes on the approach to an intersection, crosswalks, and the proper stopping points, the engineer can design the signal phasing and timing to best match the goals of the operational plan.

Guidance

02. Pavement markings should be used at highway traffic signal locations as provided in Part 3. If the road surface will not retain pavement markings, signs should be installed to provide the needed road user information.

01. 4A.07

§4A.10 Responsibility for Operation and Maintenance¶

Guidance

01. Prior to installing any highway traffic signal, the responsibility for the maintenance of the signal and all of the appurtenances, hardware, software, and the timing plan(s) should be clearly established by the responsible agency.

02. To this end the agency should:

A. Keep every controller assembly in effective operation in accordance with its predetermined timing schedule, check the operation of the controller assembly frequently enough to verify that it is operating in accordance with the predetermined timing schedule, and establish a policy to maintain a record of all timing changes and that only authorized persons are permitted to make timing changes;
B. Clean the optical system of the signal sections and replace the light sources as frequently as experience proves necessary;
C. Clean and service equipment and other appurtenances as frequently as experience proves necessary;
D. Provide for alternate operation of the traffic control signal during a period of failure, using flashing mode or manual control, or manual traffic direction by proper authorities as might be required by traffic volumes or congestion, or by erecting other traffic control devices;
E. Have properly-skilled maintenance personnel available without undue delay for all signal malfunctions and signal indication failures;
F. Provide spare equipment to minimize the interruption of highway traffic signal operation as a result of equipment failure;
G. Provide for the availability of properly-skilled maintenance personnel for the repair of all components; and
H. Maintain the appearance of the signal displays and equipment.