Conditions for breaking a work zone into multiple road events

[sknick-iastate]

Issue name: “[Clarification/Question — Work Zone Events Description/Clarification”

Summary

Their currently is no exact definition of what a work zone event is in the specification which leave this open to interpretation. After discussing with some other I thought I would put my interpretation and get feedback from others.

The work zone event isn't a single record for the entire work zone but can be separated into different components based on changes in the roadway or work zone configuration. So multiple road_event_id can make up a single work zone. For example, if a work zone starts with one lanes closed then a couple miles down the road changes to two lanes closed, we would represent that as two separate road events since the number of closed lanes change. Another example could be when one lane is closed then a lane is added because of a ramp, since the total number of lanes have changed we would separate that as two separate road events. It may not be the proper application but in both situations we plan on using the subidentier as the link to relate these projects together. This may also be very applicable to intersections where each approach has an event.

This does not impact situations such as a double lane closure https://mutcd.fhwa.dot.gov/htm/2009/part6/fig6h_37_longdesc.htm. In these lane closures we would still only include one work zone event since the portion with only a single lane closed is part of the taper and not intended to be for a long distance.

Feedback/ Potential changes

I'm not sure if this is something we include in the specification or should be included as part of the best practices/guidance subcommittee. At this point I was just looking providing my perspective for other agencies to consider and looking for feedback on whether this could be better accomplished.

From talking with others this may potentially resolve some of the other issues in lane number and references.

Some other things to consider:

• Is using the subidentifier appropriate to relate work zones or should a different field be added?
• Right now we are just considering lanes for breaking work zone events. I don't think we need to break at every attribute in the WZDx but are their higher level attributes where work zone events should break at? Some of the ones discussed are total number of lanes, number of lanes open/closed, intersections, and road name.

Looking forward to further input

[brookesc4]

There is a higher level at which work zone need to broken at and that is not only the number of lanes but what is taking place and what type of traffic control. This level of detail is needed because it affects what we may expect from a driver assist system or a human driver. For example a concrete patching operation normally uses drums or 42" devices, and traffic is often placed on the shoulder and crosses the edge line that is not removed for this type of work. Knowing that the lane keep may need to be turned off or something could tell someone a shift is taking place. This is the same in the middle of a work zone. The number of lanes may not change but what the driver or vehicle is asked to do often does. Shifting at bride locations, going from solid lines on the road in narrow sections, to no passing sections to a shoulder closure to a merge point. These are just some of the minor things that can take place within a standard lane closure and we should be capturing this.

The type of work zone device being used is also a key factor as to if there will be an escape path or open shoulder to pull over too. If you are in a two lane section with barrier wall you dont have a shoulder to utilize as a driver or a vehicle if something breaks down. You also may have a point where you have the same number of lanes open but you split merge them (one lane on the other bound) so you have two lanes traveling or open in that direction but they aren't next to each other so the lanes need to be noted differently. You can't call those lanes 2 lanes open, and have 2 lanes open be called the same thing as they drive completely different. A human driver will easily know and see this but CV will need to be told that difference.

I think you could bin this as positive protection/separation, channelizing devices, and fixed channelizing devices - (lane separator systems). with a lane separator system that is affixed to the roadway that can be used as a path to follow were drums or normal channelizing devices can move in the wind or when hit so its the level of expectation that a CV could follow the edge with and what it would need to look for and be concerned about.

We also would most likely want to note the exit and entrance ramp locations and type. Possibly a high speed and low speed. Reason being is this can help control the flow of traffic and if you have a short on ramp that is causing vehicles (maybe heavy trucks) to merge at a very slow rate of speed you would want the right lane (assuming right merge ramp) to know about this and adjust speed to make a smooth natural movement without breaking up the mainline flow. This would help give CV an idea of the gap and space that would need to be provided. If the lane has a larger merging area the space and gap would be smaller due to the merge taking place at closer to highway free flow speeds. These minor changes will need to be tracked and noted for optimizing the system in the future so we should consider this level of detail today, even though it may not all be used in the near future I think there would be a need to know this information.

hope I hit the point on what you were looking for with this question.

[Mahsa-Ettefagh]

Comments received during the V3 Specification Update Subgroup meeting on 4/29/2020:

• Ross Sheckler: We are working on a definition of an event-day to measure some of this.
• Ariel Gold (USDOT): how would this impact the ability to track level of work zone activity across jurisdictions?
• Ross Sheckler: This is particularly important with the moving operations case
• Jim Williams (INRIX): To clarify, is solution 1 a specific tag for the work zone activity that can apply to multiple events? Such as "expanding roadway n from MP 1 to 10" and then apply that to two separate events, one affecting MP 1 to 5, the other 5 to 10?
• Jianming Ma (TxDOT): mobile vs. stationary operations?
• Weimin Huang (HERE): is there a measure for diversion, MUTCD makes a difference between Detour and Diversion, diversion is when traffic is diverted onto a temporary facility placed around the work zone.
• Neil Boudreau, MassDOT: There is certainly a lot to discuss on this and it may be best served to allow for feedback between meetings with a follow up next month. I certainly see the need to address this
• Pier Castonguay (Ver-Mac): Have to keep in mind evolving lane closures that might move over time on the workzone which changes the lanes specifications at different positions depending on the day.

[j-d-b]

Based on how discussion has gone I'd propose changing the title of this issue to something like "Conditions for breaking a work zone into multiple road events". Thoughts?

[sknick-iastate]

Agree, that is more along the lines what we are trying to achieve.

[j-d-b]

Closing as this is now outdated and covered in the Creating a WZDx Feed guide.

For some history, for those who find this thread in the future:

Any time a property of a work zone changes, such as the road it's on, the number of open lanes, etc, the work zone must be represented by multiple road events, one for each segment where the properties are constant.