Motorists frequently traveling SR 4 between Skamokawa and Longview will likely have noticed changes in zones where passing other vehicles is allowed.

Eagle reporters contacted Washington Department of Transportation officials to learn about the changes, where they've occurred, and why the changes were needed.

Here is a response from WSDOT Traffic Operations Engineer David E. Burkey, edited for brevity:

In summer 2021, we resurfaced roughly a 25-mile stretch of State Route 4 . . . The work provided an opportunity to make proactive safety improvements along the corridor, including restriping sections of highway and pedestrian/bike modifications near Cathlamet.

We adopt the Manual on Uniform Traffic Control Devices (MUTCD). The MUTCD is published by the Federal Highway Administration (FHWA) and defines the nationwide standards to install and maintain traffic control devices on all public streets, highways, bikeways, and private roads open to public travel. The MUTCD defines no pass stripes in Section 3B.01. The MUTCD contains criteria . . . to determine sections that shall be striped for no passing.

Sections of highways that require the installation of no-pass stripes include vertical and horizontal curves and at railroad grade crossings on roads that have a centerline stripe. The MUTCD does allow the installation of no-pass stripes ‘at other locations where the prohibition of passing is appropriate' and at locations with ‘inadequate sight distances or other special conditions.'

No-pass striping can be classified into categories: required markings and markings for special conditions. Back in 2005 we performed range tracking (equipment that calculates no-pass markings) on all of our routes which established where all the MUTCD passing zones had the required sight distance for passing, see below.

Required no-pass stripe markings

The MUTCD Section 3B.02, No-Passing Zone Pavement Markings and Warrants, describes the required no-pass zone markings under three “Standard” headings. A few of the required conditions for no-pass stripe markings are:

--Two-way roadways at lane reduction transitions, and

--On approaches to obstructions that must be passed on the right, and

--On approaches to highway-rail grade crossings, and

--At other locations where the prohibition of passing is appropriate, and

--On two-way, two- or three-lane roadways where centerline markings are installed, no-passing zones shall be established at vertical and horizontal curves, and

--Other locations where an engineering study indicates that passing must be prohibited because of inadequate sight distances, or other special conditions.

Markings for Special Conditions

One of the tools in the “traffic calming” tool box involves striping/pavement markings and can consist of a number of things such as wider lines (which we have implemented in a few communities), channelization additions (implemented in Cathlamet), narrower lanes, and no-pass striping for special conditions. The balance between providing enough opportunity for passing and restricting passing is tricky and there is not a lot of definitive information or studies available on what is appropriate or works best. Our Traffic Office makes their determination off of a number of minimum requirements and best practice guidelines available to them. The Region Traffic Engineer has the final approval authority.

There were several existing passing zones we removed (re-striped to no passing) on the recent chip seal on SR 4. Our Traffic Office made these determinations. Here are the locations and determinations:

--WB passing zone MP 36.89 – MP 37.05 – vicinity City of Cathlamet where there is a new regulatory speed limit reduction for pedestrian improvements to discourage passing approaching the city.

--WB passing zone MP 42.66 - MP 42.82 – short section with passing lanes in opposite direction. Vehicles passing in the opposite direction do not expect vehicles to be passing in this area and/or can be partially obscured by other vehicles. To minimize the risk of high-speed head on crashes, we removed the passing in this area.

--WB passing zone MP 43.21 - MP 43.43 – short section with passing lanes in opposite direction. Vehicles passing in the opposite direction do not expect vehicles to be passing in this area and/or can be partially obscured by other vehicles. To minimize the risk of high-speed head on crashes, we removed the passing in this area.

--EB passing zone MP 49.13 – MP 49.37 - short section with passing lanes in opposite direction. Vehicles passing in the opposite direction do not expect vehicles to be passing in this area and/or can be partially obscured by other vehicles. To minimize the risk of high-speed head on crashes, we removed the passing in this area.

--Both Directions MP 50.19 – MP 50.66 – vicinity of Community of Stella where we are working with an upcoming regulatory speed reduction and have recent crash history and to discourage passing within the community.

In these instances, our traffic office took a look at the locations and crash history in these areas. On the Stella and Cathlamet areas, we worked with local agencies as well as the Washington State Patrol (WSP). The other three zones were related to locations with existing passing or truck climbing lanes in the other direction.

WSP was included in the discussion but did not overwhelmingly support these changes. We are aware that one of the effects of removing passing opportunities are that it may result in more frustration for drivers. We take that into consideration on our data-informed decisions, and in this case determined that the removal of passing in these areas will improve overall safety on the SR 4 corridor.