All-Way Stop Petition at a High-Speed Rural-Suburban Intersection
You are reviewing a citizen petition requesting an all-way stop at a suburban intersection where a two-lane major road posted 55 mph meets a residential street posted 25 mph. The major road carries about 400 veh/h in the average of the highest eight hours; the residential street carries about 60 veh/h in those same eight hours. The minor street already has STOP signs on both approaches. Over the last three years the intersection recorded four reported crashes: three angle crashes in which a minor-street driver pulled into the path of a major-street vehicle, and one left-turn crash. None produced an injury worse than possible. A nighttime condition check found both STOP sign legends reading well below the agency's minimum maintained retroreflectivity, and the east-approach STOP sign is partly screened by a low tree branch. The agency has funding for exactly one corrective action this quarter, and the petition has been forwarded to you with a request for a written recommendation.
1. Determine whether the all-way stop meets MUTCD warrant conditions. Identify each condition you test, the thresholds, and your conclusion.
Read the worked answer
Multi-way stop installation is governed by warrant conditions that must be satisfied before the control is installed; a petition is not a warrant.
Condition A - crash experience. The threshold is five or more reported crashes in a 12-month period that are susceptible to correction by a multi-way stop. Here: four crashes in three years, roughly 1.3 per year. Fails the threshold by a wide margin, and the crashes are not concentrated in a single 12-month window.
Condition B - vehicular volume. The threshold is a major-street volume averaging at least 300 veh/h in each of the same eight hours and a minor-street volume averaging at least 200 veh/h in those same eight hours. Major street: 400 veh/h, passes. Minor street: 60 veh/h, fails by more than a factor of three.
Condition C - combination. Typically the 300/200 values are reduced (commonly to percentages of the base values) and applied where neither A nor B is fully met. Even at a reduced threshold, 60 veh/h on the minor street does not come close.
Conclusion: No multi-way stop warrant is satisfied. Converting a 55-mph major road to all-way stop would also create a stopping-expectancy problem for major-street drivers who have never had to stop there, which is the classic wrong-way-to-wait rear-end generator. Recommend against.
2. Given one funding action this quarter, what do you recommend, and how do you justify it against the petition?
Read the worked answer
The highest-value action is not a control change, it is restoring the existing control so it works. A STOP sign whose legend is below minimum maintained retroreflectivity is a compliance failure independent of any crash pattern, and at this intersection it sits on the approach generating most of the angle crashes.
Recommendation, in order:
- Replace both minor-street STOP sign faces now, and confirm mounting height and lateral offset while the crew is there. Verify the sheeting type is appropriate for rural night conditions.
- Trim the branch screening the east-approach sign the same week - a free corrective action that costs nothing from the budget line.
- Add an advance warning sign on the minor street where approach speeds suggest drivers are surprised by the stop.
- Schedule a daytime and nighttime field review of the sight triangle from the minor street, since all three angle crashes share one failure mode: the driver did not see the conflicting vehicle, or did not see the sign.
- Document the warrant analysis in writing to the petitioner, and place the intersection on the list for a longer-range study of a roundabout or signal if volumes change.
Why this order: the crash pattern is consistent with a visibility/expectancy problem on the minor approach. Changing the major-street control does nothing to fix a driver who never saw the sign, and it degrades safety on a 55-mph road.