Use of Freeway Shoulders for Travel — Guide for Planning, Evaluating, and Designing Part-Time Shoulder Use as a Traffic Management Strategy
Chapter 8. Implementation Process
This chapter presents “how to” information to help agencies implement part-time shoulder use once a decision to use it has been made. The chapter will also help agencies still in the planning stages understand the steps generally taken to implement part-time shoulder use.
Design Exception Process
States are required to obtain design exceptions from Federal Highway Administration (FHWA) if the minimum values of the controlling criteria presented in the Geometric Design section of Chapter 7 of this Guide are not met on roadways that are part of the National Highway System. Part-time shoulder use may impact a number of the controlling criteria, and by definition it impacts shoulder width when the shoulder is open. AASHTO standards require a minimum freeway lane width of 12 feet and a minimum freeway shoulder width of 10 feet (except the left shoulder of 4-lane freeways, which has a minimum width of 4 feet). Therefore, unless an existing shoulder is at least 22 feet wide (or 16 feet wide in the case of a left shoulder on a 4-lane freeway), a design exception will be required when static or dynamic part-time shoulder use is implemented. Design exception practices for bus-on-shoulder (BOS) vary.
The key piece of a design exception request is an explanation of why it is infeasible to meet AASHTO standards. Meeting standards on part-time shoulder use is equivalent to conventional widening, and part-time shoulder use is likely being considered because conventional widening is infeasible in terms of cost or right-of-way (ROW) requirements.
Design exception requests should also include an evaluation of the implications of substandard features and how they are mitigated on a specific facility. In the case of part-time shoulder use, the following may mitigate substandard geometry:
The specific requirements of design exception requests vary by state. Design exceptions are typically submitted to and approved by FHWA Division Offices, although they may allow approval on their behalf by state departments of transportation (DOTs) or local agencies.(50) Part- time shoulder use may have a relatively short implementation timeframe compared to conventional projects, so a design exception request should be prepared and submitted to FHWA as early as possible in the planning process. Design exception requests are typically reviewed in conjunction with the overall review and approval of the plans, specifications, and estimates, which may be relatively minor for part-time shoulder use.(50)
FHWA approval process for part-time shoulder use has varied. In Massachusetts, approval was granted on a temporary basis when part-time shoulder use was first implemented in 1985 and renewed several times before permanent approval was granted in 2009.(49)
Most part-time shoulder use projects that have recently been implemented or are currently in the planning process are long-term implementations. Temporary approval is not recommended because it creates the need for re-approval.
Many states also have design standards, manuals, or laws that may need to be updated prior to implementing part-time shoulder use. Minnesota, which has nearly 300 miles of BOS facilities, developed standards for BOS facilities in the 1990s with input from their FHWA Division Offices.(44) The standards were incorporated into MnDOT’s design manual. Washington State, which is planning several part-time shoulder use and Active Traffic Management (ATM) installations, is developing an urban freeway retrofit guide with the help of their FHWA Division Office.(33)
In some states, driving on the shoulder is prohibited by law, and implementation has required legislative action or new rulemaking and agreements to interpret existing laws. For example:(42)
MUTCD Experimental Approval Process
If “a new traffic control device or a different application of an existing device” is “not compliant with or not included in the MUTCD”, the state DOT considering its installation should submit a request to experiment to FHWA MUTCD team, and FHWA must approve the experiment before the control device is installed.
Most part-time shoulder use projects have not used experimental traffic control devices. Control devices commonly used on part-time shoulder uses facilities that do not require experimental approval include the following:
However, more-complex part-time shoulder use projects, such as those with other ATM
The request for experimentation should originate with the State DOT and be sent to FHWA Headquarters with a courtesy copy to the FHWA Division Office. The FHWA must approve the experiment before it begins. All requests should include the following:(51)
Successful deployment of part-time shoulder use requires a well-planned, interdisciplinary collaboration with a variety of different stakeholders, including planning, operations, design, maintenance, and executive leadership staff within a DOT; law enforcement; emergency responders; bus operators; MPO staff; and FHWA Division Office staff.
A state DOT will typically be the agency that decides if part-time shoulder use is feasible, possibly in collaboration with a transit agency if BOS is under consideration. As soon as this determination is made, the state DOT should reach out to the stakeholder groups noted above and form a working group. Most agencies that have successfully implemented part-time shoulder use have formed working groups to ensure the needs of all stakeholders are incorporated into the concept of operations. Stakeholder involvement and education—assuming that some stakeholders may not be aware of the benefits and potential issues associated with part-time shoulder uses—is an ongoing process and working groups should continue to meet during the early years of a part-time shoulder use facility’s operation. Engaging executive leadership early is critical because policies may need to change and laws potentially prohibiting driving on the shoulder may need to be interpreted or changed.
For stakeholders who do not have a working knowledge of part-time shoulder use, implementing an education and outreach program during the early stages of the effort will help build trust in the proposed investments. This education and outreach effort can include peer exchanges, involving counterparts from other states or countries with shoulder running experience, as well as FHWA.
The traveling public is also an important stakeholder, and their engagement is discussed later in this chapter.
Incorporating and Mitigating Emergency Response and Incident Management Concerns
Emergency responders frequently drive on shoulders to reach incident scenes and use shoulders to park while responding to incidents. Concerns over the potential loss of the ability to bypass congested traffic and remain out of the travelled way when responding to incidents need to be addressed before part-time shoulder use is implemented, particularly for longer part-time shoulder use sections spanning multiple interchanges.
Incident response plans developed during the planning of part-time shoulder use can mitigate these concerns. “Sweeps” of the shoulder before it opens and the construction of turnouts reduce the likelihood of the shoulder being blocked. A fleet of dedicated incident response vehicles positioned at multiple locations along the facility can also decrease incident response times.
If dynamic signs are used, additional incident management and response options are available. Local emergency response agencies should be given the authority to order the closure of the shoulder and have a clear line of communication to the TMC for doing so. Closing the shoulder clears it of vehicles and provides emergency responders with an uncongested path to incident scenes.
Incorporating and Mitigating Maintenance Concerns
Maintenance concerns with part-time shoulder use typically relate to how the lane designated for part-time shoulder use should be maintained—more similar to a shoulder or more similar to a travel lane, how existing maintenance activities will be impacted, and what new maintenance activities will be required.
Agencies with part-time shoulder use have generally come to the conclusion that shoulders should be maintained in the same manner as other lanes, and nothing outside of typical maintenance operations needs to be done with regard to filling potholes, plowing snow, and so forth. Existing maintenance activities requiring stopping on the shoulder cannot occur when the shoulder is open but are otherwise unaffected.
New maintenance needs vary greatly depending on the type of part-time shoulder use. BOS and static part-time shoulder uses with no additional ITS have virtually no additional maintenance needs beyond maintaining the shoulder as a lane. Extensive ITS hardware used for dynamic part- time shoulder use and other ATM systems likely require additional maintenance staff and staff training with regard to the specifics of the technology.
Incorporating and Mitigating Bus Operator Concerns
Minnesota began widespread implementation of BOS operation in the Twin Cities metropolitan area in the 1990s. Their methods of mitigating bus operator concerns are well-established and have served as a model for many other states that have subsequently implemented BOS.
On routes designated for BOS, Minnesota limits BOS speed to 15 mph faster than adjacent traffic and an absolute maximum of 35 mph. This ensures BOS occurs in a relatively low-speed environment with low speed differentials. The choice to use the shoulder is up to each driver, although passengers sometimes complain if speeds are low enough to permit part-time shoulder use and drivers choose not to use it. Metro Transit, the largest bus operator in the Twin Cities, allows drivers who are uncomfortable driving on the shoulder to request transfers to other routes. The primary requirement for a bus using the BOS lanes is for the driver to have received training. Transit agencies using the BOS lanes offer training several times a year, and new drivers are assigned to routes without BOS if they have not yet been trained.
Similar to other innovative transportation projects, public outreach is a critical part of part-time shoulder use implementation. Successful implementation of the first part-time shoulder use project in a metropolitan area includes explicit and proactive outreach and education to the general public and should be undertaken consistent with state public information guidance. This would create opportunities to familiarize others with the concept of part-time shoulder use and the details of how it will work on a specific facility. How will drivers know if the shoulder is open or closed? What special signs will be used? Will the speed limit change? What should drivers do if they break down? Creating multiple forums to engage the public (including presentations at local council or board meetings, briefs at community organization functions, and project-specific open house meetings) results in opportunities to listen to community interests and share objective information about part-time shoulder use.
Public outreach conducted during planning a part-time shoulder use project can inform and educate the public about proper use and benefits. Media campaigns through local newspapers, television, and public meetings can be effective methods of keeping the community informed. Once the part-time shoulder use project is open to the public, monitoring driver behavior and using law enforcement as necessary to promote proper use of the part-time shoulder use can aid driver acclimation. Figure 39 shows a postcard handout that has been used at public meetings in Michigan in preparation for an ATM installation.
The following communications and public involvement elements may be considered as part of the public outreach:
United States Department of Transportation - Federal Highway Administration