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Three-way stop on Mesa Road


There is now a three-way stop at the top of the Mesa Road. When the stop signs first appeared, there was widespread outrage expressed by staff because it was noted that requiring a full stop was more hazardous than having no stop signs at all, and stop signs were not necessary. In all the years I've driven up the hill, I've never had a problem at that intersection. In fact, if anything, there is even less hazard in the last couple of years since they banned all vehicles except NCAR shuttles from going up the lane to the front door. At most, there are only two to three shuttles per hour at that intersection coming from the Mesa Lab’s front door lane. And for all other traffic on the Mesa Road, likely amounting to 30 or more vehicles per hour, and many more during morning and evening rush hour, there is an annoying full stop required where none was ever necessary before, and is not necessary now.

Due to the outcry when the stop signs first appeared, I heard a rumor that management reasonably saw the need for yield signs on the Mesa Road, with a stop sign coming from the Mesa Lab’s front door lane, NOT a three-way stop. However, the stop signs are still there, and now I hear a rumor that the security guards will start monitoring scofflaws who treat the stop signs like yield signs, with possible disciplinary action.

This is unnecessarily escalating a situation that can be readily fixed by just replacing the two stop signs on the NCAR hill road with more reasonable, and just as safety-effective, yield signs. Wouldn't this be more rational, reasonable, and very easy to do, as opposed to asking the security guards to start acting as policemen and going after staff?

Answered on April 06, 2011


The redesign of the Mesa Lab approach road, with the inclusion of a dedicated uphill bike lane and a pedestrian-only sidewalk, triggered a fresh look at the multimodal traffic patterns that are now formalized by the concrete bike lane, concrete sidewalk, and designated pedestrian crossings. The wording in the question above takes a very automobile-centric viewpoint. The safety issues at this intersection extend also to pedestrians and bicyclists that use our access road and hiking trails. For a further explanation we asked Aaron Heumann, the professional transportation engineer from Martin/Martin Engineering who designed the traffic controls for the intersection and road, to provide an explanation of the rationale for the all-way stop.

“Intersection traffic control follows the regulations and guidelines established in the Manual on Traffic Control Devices (MUTCD) developed by the Federal Highway Administration. The MUTCD discusses multi-way stop control, which includes considerations for safety associated with the presence of pedestrians and bicyclists or lack of adequate sight distance as justifiable applications based on engineering judgment. In specific, the MUTCD states support for multi-way stop control where: ‘Safety concerns associated with multi-way stops include pedestrians, bicyclists, and all road users expecting other road users to stop.’

In addition, there are optional criteria for multi-way stop control applications where there is: ‘The need to control vehicle/pedestrian conflicts near locations that generate high pedestrian volumes.’ And also for: ‘Locations where a road user, after stopping, cannot see conflicting traffic and is not able to negotiate the intersection unless conflicting cross traffic is also required to stop.’

Due to the expected multiple users of the intersection, marked crossings through the intersection, potential for substantial conflicts between vehicles and pedestrians/bicyclists, the poor sight distance for vehicles approaching the intersection from the ramp looking to the left, and the need to transition from a long entryway roadway into a potentially congested and active parking area, based on our experience and engineering judgment we felt it was prudent to control the intersection with a multi-way stop control.”

Regarding the enforcement part of the question, there are no changes planned from past practices. If complaints are received from staff then Health, Environment & Safety Services (HESS) investigates and works with the offending employee. This is the exact same process that has been in force for the last 25 years.

Please use common courtesy to the level that you would expect in your own neighborhood. Please treat the stop signs as full stops and not yield signs. A few extra seconds in your day to ensure the safety of pedestrians, hikers, and bikers, whether visitors or staff, is surely worth the time.

Matt McMullen
Director, Facilites Management & Sustainability