All You Need to Know About All-Way Stops

By Laura Slusher, PE, LTAP Traffic Engineer 

All-way, or multi-way, stop-controlled intersections are commonplace in Indiana. However, where this particular type of traffic control should be used is often misunderstood.  When misapplied, all-way stops can create more problems than a traditional two-way stop-controlled intersection. This article will clear up any misconceptions about all-way stops so your agency can better understand how to use all-way stops as a safe and effective method of traffic control.

The Indiana Manual on Uniform Traffic Control Devices (MUTCD) provides guidelines for installation of all traffic control devices, including stop signs. By utilizing the IN MUTCD, local agencies create a consistent experience for all roadway users and also limit their liability. The IN MUTCD details right-of-way at intersections and the requirements of stop sign installations across several sections, specifically Sections 2B.04 – 2B.10.

For local agencies, one of the key takeaways from the IN MUTCD is the installation or removal of a stop sign should be done by an engineering study. This stipulation ensures stop signs are not installed where they are not needed, or where they may do more harm than good. When drivers perceive no need to come to a complete stop, they often just roll through the intersection instead of stopping. Unwarranted stop signs exacerbate bad driver behavior not only at the unwarranted locations, but at all intersections. 

The IN MUTCD has clear guidelines about where stop signs and all-way stops are warranted. Section 2B.07 details the guidelines the engineer should consider before installing an all-way stop. One of many considerations is traffic volumes. All-way stops are typically used where both intersecting roads have similar levels of traffic. When obtaining traffic counts for an intersection, make sure to get directional data since traffic volume warrants use approach volumes, not Average Daily Traffic (ADT).

Many rural intersections in the state will not meet the volume guideline to warrant the installation of an all-way stop. The minimum level of traffic on high-speed, major street approaches is 210 vehicles each hour over an eight-hour period. On the minor street approaches, the minimum volume for the same eight-hour period is 140 roadway users each hour. For a point of reference, that means the ADT would be well over 2000 vehicles per day (vpd) on the major road and well over 1000 vpd on the minor road.

In addition to traffic volumes, other data considered by engineers before installing all-way stops are crash experience, vehicle speeds, delay, sight distance, driver expectancy, left turns, and pedestrians. This is not a complete list since an intersection may have unique characteristics requiring engineering judgment to determine what data is pertinent for each intersection study.

One common misapplication of an all-way stop is to deter or slow down drivers. Research has shown this tactic is not effective and often may cause drivers to speed up after the unwarranted stop sign since they did not see a need for it. The IN MUTCD specifically states, stop signs should not be used for speed control. Agencies worried about speed control should look at traffic calming measures to effectively slow traffic.

If your agency has all-way stop-controlled intersections, the IN MUTCD (Section 2B.05) requires installing the ALL WAY supplemental plaque (R1-3p) beneath each stop sign at that intersection. Other supplemental plaques, such as 2-WAY, 3-WAY, 4-WAY, can no longer be used with a stop sign. If you have any of these outdated plaques, make plans to have them replaced with the ALL WAY plaque as soon as your budget allows. If drivers are confused at an intersection that is not an all-way stop, there are other supplemental plaques that can provide more information to help drivers, such as CROSS TRAFFIC DOES NOT STOP (W4-4p).

By following the IN MUTCD when installing all traffic control devices like stop signs, as dictated by IN Code 9-21-4-1, local agencies are putting themselves in a legally-defensible position should a lawsuit arise. Lawyers are familiar with the IN MUTCD and will often attribute negligence if it is not followed. So next time someone asks to put in an all-way stop, make sure to contact your agency engineer or LTAP to determine if that all-way stop is indeed a good idea.