Passing/No Passing Zone Guidelines

CENTERLINE MARKINGS ON TWO LANE BI-DIRECTIONAL ROADS

Most of the rural highway network is the two -lane, two -way highway and much of this mileage was constructed before modern geometric design standards were established.  Consequently, the horizontal and vertical alignments create hazards that frequently are the indirect cause of many crashes.  A contributing factor to crashes occurring on two-lane, two-way highways is the limited sight distance due to poor alignment, that exists on these roads.  Sight distance is especially important on two-lane, two-way highways because the passing maneuver requires the use of the lane normally occupied by oncoming traffic.

Performing a passing maneuver on a two-lane rural highway can be one of the most difficult and potentially hazardous tasks for a driver.  The successful execution of a passing maneuver depends on the complex relationship between the driver, the vehicle, and the environment where the maneuver occurs.  The use of passing zones on two-lane roads, when designed appropriately, may improve traffic operations by providing a safe area for free-flowing traffic to pass slow-moving vehicles that are typically found on rural highways, such as agricultural machinery or large trucks.  However, improper use may reduce safety by encouraging speeds greater than the posted speed limit and/or by introducing unanticipated driver maneuvers.  Criteria and guidelines for establishing passing and no passing zones vary substantially from State to State.

AUTHORITY

Section 14-234 of the Connecticut General Statutes authorizes The Office of the State Traffic Administration to determine those portions of any state highway where overtaking and passing or driving to the left of the highway would be especially hazardous and may, by appropriate signs or markings on the highway, indicate the beginning and end of such zones.  In other words, the Office of the State Traffic Commission is authorized to establish No-Passing Zones on State Highways and a local traffic authority, as defined in section 14-297, may, in accordance with standards approved by the Office of the State Traffic Administration, determine and designate such no-passing zones on highways under its jurisdiction.

Section 14-235 of the Connecticut General Statutes states in part that “No vehicle shall be driven to the left side of the highway (1) when approaching the crest of a grade or upon a curve or elsewhere in the highway where a free and unobstructed view of the highway ahead may not be had for a sufficient distance to insure driving with safety or (2) when approaching within 100 feet of or crossing any intersection or railroad grade crossing.”

This guideline scope is limited to two-lane bidirectional State Highways. The Office of the State Traffic Administration also recommends that municipalities adopt these criteria when evaluating centerline marking on roads under their own control.

RECORDS

The Office of the State Traffic Administration maintains centerline marking records for undivided State Highways.

• For new construction or reconstruction by Sate Project, the Division of Traffic Engineering, in consultation with OSTA, will review and determine the need to establish or revise the centerline markings on a state highway impacted by a state project.
• For annual District Maintenance resurfacing projects, OSTA engineering staff will review and determine the need for centerline marking revision.
• For encroachment permit related revisions, the District Maintenance Office will review and consult with OSTA engineering staff, regarding the need for centerline marking revision.
• For Local Traffic Authority Requests to install, remove or revise a no- passing zone on a State Highway, OSTA engineering staff will review and determine the need for centerline marking revision.

SUPPORTING REFERENCES

A Policy on Geometric Design of Highways and Streets (AASHTO Green Book), 2018 Edition:

• Section 3.2.4, Passing Sight Distance for Two-Lane Highways

Manual on Uniform Traffic Control Devices for Streets and Highways (MUTCD), 2009 Edition:

• Chapter 2B, Regulatory Signs, Barricades, and Gates
• Chapter 2C, Warning Signs and Object Markers
• Chapter 3B, Pavement and Curb Markings

DESIGN CRITERIA AND RESTRICTIONS

Minimum passing sight distance and minimum passing zone length requirements vary in length depending on the posted or 85th percentile speed of vehicles on a particular section of highway.  These minimum distances meet or exceed those outlined in the Manual on Uniform Traffic Control Devices (MUTCD), latest edition.

Existing passing zones that meet criteria may still be removed if a review of safety and/or speed data indicate the passing zone is contributing to a safety problem.

The minimum sight distance for a passing zone in any single direction shall meet or exceed:

The minimum length of a passing zone in any single direction shall meet or exceed:

Passing zones that meet or exceed the minimum sight distance and passing length requirements should not be removed because of minor driveways or private roads.

NO-PASSING ZONES shall be established:

• When the minimum passing sight distance requirements at horizontal or vertical curves is less than the minimum shown in MUTCD Table 3B-1 for the 85th-percentile speed or the posted or statutory speed limit.
• For a minimum distance of 200’ approaching and 100’ departing the following:
• Railroad grade crossing
• Traffic control signal
• Stop sign
• Roundabout
• Special pavement marking, channelization, median or island
• Designated School Zone or school driveway
• Marked crosswalk
• When a sudden or severe narrowing of a roadway that produces a tunneling effect to an approaching vehicle in conjunction with the presence of fixed objects (i.e., guidepost or rail, bridge wall, trees, etc.) close to the traveled way may be considered an obstruction
• Hospital, fire, or other driveway serving emergency services
• Intersection with a public way
• A school or transit bus stop
• Any other driveway for a State Park or unsignalized significant traffic generator or cluster of driveways that would collectively generate significant traffic.
• Where the distance between successive no-passing zones is less than 400 feet, no-passing markings should connect the zones.

Minimum distance may be increased when engineering study indicates additional length would improve safety.

TRAFFIC CONTROL DEVICES

Markings
No passing zones shall be indicated by solid yellow pavement markings; passing zones shall be indicated by broken yellow pavement markings. Where passing is allowed in a single direction and prohibited in another, the yellow marking closest to the passing zone shall be broken and solid adjacent to the no passing zone (see Figure 3B-1 of the MUTCD). Where passing is prohibited in both directions, a solid double yellow line shall be used.

Signs
The downstream terminus of a passing zone should have an R4-1 DO NOT PASS (31-1502) sign posted to the right of the road. In cases where either compliance is low or engineering judgement determines additional emphasis is needed, a W14-3 NO PASSING ZONE pennant sign (41-1503) may be added to the left side of the road, directly opposite the R4-1 (31-1502).

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