3.3.1. Rules for drawing roads and sections of road

Attention.

Be careful when drawing roads. The road network is used to set routes, so drawing errors can lead to routing mistakes.

Techniques for drawing and editing road sections are similar to the techniques for drawing and editing all linear items on YME.

For their descriptions, see Sections 2.6.1.1. Drawing simple linear items and 2.6.1.2. Editing simple linear items.

There is a tool for drawing circular road sections.

When you draw a road section, keep in mind that certain drawing rules relate to features of the road in question (rather than to that particular road section). For example, some roads are drawn with a single line and others with two lines (for more information, see Section 3.3.1.2. Rules for drawing roads in one/two arcs (one or two lines)).).

This is why the drawing rules for sections of road include:

When drawing road elements, the points where the road elements intersect (the start or end point of each element) form independent objects of type “Intersection”. Intersections are created automatically when drawing road sections and can be used to edit the road network (for more information, see Section 2.9. Intersections) and to set road conditions, traffic lights, and speed cameras.

When drawing roads, do not create road sections and their intersection boundaries excessively. The start and end points of road sections must overlap:

  • — With intersections

  • — With points where road section attributes change their values (such as changes in speed limits, or a road section passing the boundary of another traffic installation like a bridge or a tunnel, etc.)

  • — With points where a road section passes a boarder of another country (see section 3.3.1.1.7) or locality (see section 3.3.1.1.9)

  • — With a number of Places, such as:

3.3.1.1. Drawing rules for whole road networks

3.3.1.1.1

Road networks should be connected: all fragments of a road network that forms in a given area should be connected on the map. For example:

Correct Incorrect




If you can only get to a certain “isolated” road section by railroad or ferry crossing (but not by motorway), then the road network should include these railroad and ferry crossings, and you should add attributes to them accordingly (see Section 3.3.2.6. Type of structure).

Roads that are under construction can be connected to road networks via lower-class roads (see point 3.2.11).

3.3.1.1.2

When you draw the road network, make sure that you don't overlap different road sections, draw a section that intersects with itself, or duplicate road sections:

Correct Incorrect




When you draw an item on the map, the program monitors if the drawing is correct and reports any errors to you:



But not all errors are recognized automatically.

3.3.1.1.3

When you draw bends in roads or intersections, the end points of road sections that form crossings should meet and form an intersection. There should not be any “hanging points” (other than in cases where the road is blocked in that area):

Correct Incorrect




3.3.1.1.4

Draw the road network from satellite images rather than tracks except for cases when the central line of the tracks isn't located within the roadbed in the image due to the terrain.

For example, when you're drawing road sections that cross bridges, pay attention to the displacement of the bridge on the satellite image (for more information, see Section 2.3.1.4. Bridges).

If the images are significantly displaced from the tracks, don't manually edit the geometry of the road network, instead reporting the large-scale shift using the feedback form.

3.3.1.1.5

You don't have to include certain minor details in your drawing of the road network.

You shouldn't draw individual entrances to every home in a private development:

Correct Incorrect

This restriction does not apply to:

  • Class 10 paths with hard surface located within parks and squares that form a regularly-shaped pattern. For such cases, you should fully draw the whole path network. For example:

  • Pedestrian paths leading to building entrances and individual organizations if these paths are physically distinguished from the surrounding area. The paths are drawn strictly to the entrance, stairs, porch, or other similar objects:

  • Roads that pass through public (not private) plots and lead to residential buildings located within blocks, on the second line relative to the main road even if they have a barrier and/or pass through an arch:

3.3.1.1.6

Only draw roads leading to roofs for buildings that belong to the “utility and storage” type.

Only draw roads in underground and multi-level parking lots in the following cases:
  1. The parking area is located under a shopping or business center.
  2. The public parking area is located in a “utility and storage” building, and the road doesn't lead outside the premises (in such cases, the minimum number of roads connecting all entrances and exits to the building can be drawn):

    Correct Incorrect
  3. The one-way entrance and exit from the underground parking are located in close proximity to each other (in this case, the entrance and exit sections should be connected in an arc within the structure without leading them deep into the building):

Note.

To ensure connectivity between roads on one-way entrances to and exits from underground parking lots, set the traffic to A ⇆ B if the roads are not located close to each other and cut off near a building's polygon.

3.3.1.1.7

Road sections that cross country borders are cut at the point of crossing. The crossing is marked as an Intersection:

Motorways that pass through several countries (which are usually Numbered highways, such as M-1 Belarus or M-2 Crimea), are cut at crossings into sections running through different territories (also see Section 3.3.3.1.1).

This allows you to link the road to the administrative division (country) where it is located. The road will be divided into fragments that correspond to the territories of the different countries that it runs through:

3.3.1.1.8

On territories that are regularly developed, vegetation may intersect with motorways that are class 10 (Pedestrian and bike paths), 9 (Forest and field roads) or 7 (Roads of minimal significance) and are only accessible to pedestrians and/or bicyclists.

Outside of territories that are regularly developed, vegetation may intersect with railways and motorways that are drawn using a single line.

Both outside of and on territories that are regularly developed, vegetation of the “Park, square”, “Nature reserve” and with “Cemetery” types may intersect with motorways of any type if these roads are exit ramps to these areas of vegetation or passages through said areas.

See also point 3.9.1.5.

3.3.1.1.9

When you draw roads that intersect with locality borders, you must split the border at the intersection point (creating two road sections).

Note.

Streets linked to a locality should be located entirely within the borders of that locality. See section 3.3.1.4.

3.3.1.1.10

Don't change the main road's shape if you're drawing the road expanding and getting new lanes near toll booths and border checkpoints. Checkpoint passages don't need dedicated lines.

Correct:

Incorrect:

3.3.1.1.11
Draw a u-turn site for public transport along the site's perimeter using the line of a class-8 road, which is one-way in the direction of public transport movement and accessible only to public transport in the following cases:
  • The u-turn site is separated from the main roadway by marking.
  • The u-turn site largely extends the roadway and includes a stop or parking area for public transport.
Correct Incorrect

3.3.1.1.12

Areas leading to gas stations should be drawn using class 8 road sections, even if they aren't separated from the main road by barriers or markings.

3.3.1.2. Rules for drawing roads in one/two arcs (one or two lines)).

There are two ways to draw roads on Yandex Map Editor:

  • In “one line” (for both one-way and two-way roads):

  • In “two lines” (one representing each traffic direction):

3.3.1.2.1. Two-line drawing

Road sections are drawn using two lines in the following situations:

3.3.1.2.1.1

When the road is a class 1 (expressway):

3.3.1.2.1.2

When a road has three or more traffic lanes in one direction or oncoming-traffic lanes delineated by a solid line (such as a road with a 3+2 lane structure):

Note.

If there is a central turning lane (as, for example, in the US) and it is the 3rd lane in one of the directions, the road is also drawn using two lines:

3.3.1.2.1.3

When the road has a physical median between the roadways:

  • a) A barrier or dividing road posts:




  • b) Lawn, flowerbed:
  • c) Tram rails elevated above the road:
3.3.1.2.1.4

When a road has two or more traffic lanes in each direction and tram rails that are not raised above street level and are used by cars (they are not counted as lanes):

Or tram rails are separated from the car sections by solid traffic lane markings:

3.3.1.2.2. One-line drawing

Every road, not having characteristics two-lane roads (see 3.3.1.2.1) must be drawn in one edge.

3.3.1.2.2.1

Don't draw additional road lines for a marked lane of oncoming or same-direction traffic of public transport:

3.3.1.2.3

If a road has multi-level interchanges, then draw the interchanges as you would the road itself (with either one or two lines):

3.3.1.2.4

For a short section of road, you should not switch between drawing one and two lines (even if the number of lanes or the road markings change). Within localities, a section less than one block long is considered a short section.

If the road has a physical divider, draw it using two lines. An exception to this rule is cases when a pair of items that physically separate traffic lanes (forming a “traffic island” at a pedestrian crossing) are positioned at a distance from each other that is less than or approximately equal to the width of the pedestrian crossing. For example, a pair of traffic lights or borders does not change the rendering of a single-lane road to a two-lane road:

You should not switch your drawing method for marked breaks in a solid double line or for a traffic island before an intersection:

Merging a two-line road into a one-line one should happen smoothly (otherwise the navigator may misinterpret the transition as a turn):

Correct

(the transition is smooth)

Incorrect

(the transition is abrupt)





3.3.1.2.5

Draw lines down the middle of the roadway (for roads drawn using one line) and down the middle of the roadway going in each direction (for roads drawn using two lines):





3.3.1.2.6

Sections of road drawn using two lines should run parallel to each other if they are parallel in reality (green arrow on the drawing). Areas where the road narrows or widens are an exception to this rule (blue arrow on the drawing):



3.3.1.3. Rules for drawing straight and curved road sections and turns

Rules for drawing straight and curved road sections (these rules supplement the general rules for drawing linear items):

3.3.1.3.1. Drawing straight sections of road

Straight sections of road should not have intermediate vertexes:

Correct Incorrect




3.3.1.3.2. Drawing curved sections of road

On curved sections of road, the number of vertexes should be sufficient so that angles at slight turns are not noticeable on maps at scale 19. You should not draw more points than are necessary to fulfill this requirement:

Correct Incorrect






3.3.1.3.3. Drawing turns

Draw turns so that they look smooth (with no angles) when viewed on a map at scale 19. You should not draw more points than are necessary to fulfill this requirement (usually three points suffices):

Correct Incorrect




To draw a smooth turn on a road, you can use the round corners tool or command.

Attention.

If the turn is part of a T formation at an intersection, adhere to the rules for drawing these types of intersections (see point 3.3.1.5.3.5).

See also Section 2.10.2. Map item: related edits.

3.3.1.4. Rules for drawing u-turns with two lines

If a road drawn using two lines has a u-turn:

3.3.1.4.1

Draw a two-way u-turn in fragments that run perpendicular to the lines you drew on the road.

If the u-turn lanes are separated from one another (by a barrier, median, lawn, or traffic island entered as markup), then draw the u-turn using two lines:





3.3.1.4.2

Draw one-way u-turns as arcs and indicate the traffic direction:



3.3.1.5. Rules for drawing intersections

Draw intersections to reflect the actual traffic situation there (in other words, take traffic signs, permitted turns, etc. into account regardless of if the roads that intersect there are drawn using one or two lines).

The following rules apply for drawing intersections:

3.3.1.5.1

If a road intersects with two different roads that only differ by name (in other words, the driver can navigate from one to the other without performing any maneuvers), then enter one general intersection point that applies to both of them (see upper drawing).

If this is not the case, then enter two intersection points (see lower drawing):









3.3.1.5.2

Only mark separate lines for turns (or exit ramps) at intersections when the lanes for the turns are separated from the main roadway by a barrier, median, lawn, traffic island, dividing line, or bus lane. Don't draw exit ramps for roads that widen by one or two lanes before an intersection.

Examples of cases where you show draw an exit ramp:

Examples of correct and incorrect exit ramp drawing:

Correct Incorrect




Example of a correct exit ramp drawing when there is a physical barrier:

3.3.1.5.2.1

If the exit is actually a separate lane (further movement of transport in directions other than the exit is impossible), the intersection with the main road is drawn at the point where the dashed line becomes solid.

For example, the drawings on the right show roads where the first lane is exclusively used for turning. The drawings on the left, on the other hand, show roads where the first lane can be used for turning or going straight:

Correct Incorrect

If the exit is not a separate lane (both exit and traffic on the main road are possible), the intersection with the main road is drawn at the point where the exit lane branches off from the outer lane.

In the image below, the blue arrow indicates the correct point for starting to draw the exit ramp, and the red arrow points at an incorrect location:

3.3.1.5.2.2
Connect exits to the main road at an acute angle, without rounding corners:
Correct Incorrect
3.3.1.5.3

When drawing intersections of one-line and two-line roads with barriers:

3.3.1.5.3.1

If one two-line road (and three one-line ones) approach an intersection, then the former may converge into a one-line road both before and after the intersection (depending on the situation):





Attention.

Make the convergence of a two-line road into a one-line one smooth (see point 3.3.1.2.4).

If two two-line roads and one one-line, one-way road approach an intersection, then the convergence of the two-line road into one-line is not drawn down the middle of the road, but rather as indicated in the drawing on the left (the green arrows indicate the permitted traffic directions):



3.3.1.5.3.2

If two two-line roads (and one or two one-line roads) approach an intersection, then the former will converge into one-line roads after the intersection:





3.3.1.5.3.3

If a two-line road forms a T-shaped intersection with a one-line road, then the former will not converge into a one-line road:





3.3.1.5.3.4

If the intersection has two-line roads and barriers, then draw the intersection to reflect where vehicles can actually pass through:

















3.3.1.5.3.5

T-shaped intersections should intersect at right angles (i.e. the corners should not be rounded). The green arrows on the left indicate an intersection that was drawn correctly. The red arrows indicates an incorrectly drawn intersection. On the right, an incorrect drawing was corrected:

Correct and incorrect Correct

This rule applies to all classes of roads, including pedestrian paths. Draw intersections where a high-class road turns and adjoins a less significant road in a similar fashion.

Correct Incorrect

Turns are only drawn as smooth curves in cases where there is a physical divider or a corresponding marker on the map:

3.3.1.5.3.6

Circular road sections should not share intersection points:

Correct Incorrect

3.3.1.6. Drawing rules for sidewalks, pedestrian paths, and bike paths

3.3.1.6.1

The Pedestrian paths class comprises the following:

  • Roads that are not wide enough for vehicles

  • Pedestrian paths

  • Sidewalks

  • Roads within parks and cemeteries

  • Pedestrian walkways across railway tracks and motorways

  • Pedestrian staircases, bridges, and tunnels

Note.

When you draw pedestrian roads and sidewalks, you can use road color-coding to represent Pedestrian accessibility (i.e. use different colors to show whether or not a road is accessible to pedestrians).

Do not draw too many unpaved pedestrian roads (paths) on a restricted area (for example, in a single courtyard), even if they can be discerned from a satellite image. It is necessary to single out the key points among them (providing access to public service points, public transport stops, etc.) and draw only them.

Note.

Significant pedestrian paths (such as Arbat St. in Moscow) are class 7 (“Streets in localities”); set the access as pedestrian-only for them.

3.3.1.6.1.1

Don't draw items that resemble sidewalks or pedestrian paths but do not function as such (for example, commercial passageways):

Narrow passages along roads that duplicate the route of the main sidewalk are also considered technical:

You also shouldn't draw individual sections of pedestrian paths if they're completely isolated from the rest of the network.

For example, the entrance to this bridge is blocked off by permanently closed gates, which is why you shouldn't draw the bridge's road section:

3.3.1.6.1.2

Sidewalks, pedestrian and Bicycle paths are drawn on a conditional basis. “axial” lines.

If an areal item is inaccessible to cars and has no visible “axial” pedestrian path lines, it should be drawn along the shortest path and at right angles if possible. You can also draw additional pedestrian paths along the perimeter of the areal item.

3.3.1.6.2

Lines representing pedestrian crosswalks, sidewalks, and pedestrian zones should form a connected network with the entire road network as a whole.

Networks of alleys and pedestrian roads running through parking lots and cemeteries should connect in the proper location to sidewalks and motorways that have the accessible to pedestrian attribute marked.

For example, the solid green line indicates a sidewalk in the drawing, the dotted line represents a network of pedestrian paths in a cemetery, and the brown line — a section of motorway. The red arrow indicates the point where they intersect. A fragment of the broader road graph is displayed on the drawing:

3.3.1.6.2.1

Fragments of the road network accessible to pedestrians might be disconnected from one another.

For example, the pedestrian roads on the island of Kronstadt near St. Petersburg form a network that pedestrians cannot reach from other areas of the city (they only connect to the A-118 freeway-ringroad).

In similar situations do not artificially link the isolated sections of the road network available to pedestrians to each other, indicating accessibility to pedestrians where it is not available.

Exceptions to this rule are allowed in the situations described in 3.3.1.6.3.6.

3.3.1.6.3. Sidewalks
3.3.1.6.3.1

Draw sidewalks as separate roads if the sidewalk is separated off from the roadway by a physical barrier (grass, fences, etc.).

Draw sidewalks that are only separated from the road by the curb as separate roads running alongside roads of class 1-7:

3.3.1.6.3.2

The shoulder of a highway is not considered to be a sidewalk; do not draw it as a separate road.

If the shoulder of a road segment is accessible to pedestrians, then don't draw it as a sidewalk running along that segment, but rather add the accessible to pedestrian attribute to the applicable segment.

3.3.1.6.3.3

To ensure connectivity of the road network in areas where the pavement ends, but the further movement of pedestrians is possible on the side of the road, should smoothly join the line of the sidewalk and the road segment pedestrian road (in the picture the green dotted line):

3.3.1.6.3.3.1

Don't draw technical connections between pedestrian roads and sidewalks on freeways (class 1 roads). For example, the sidewalk line at a stop on the MKAD (Moscow ring road) ends on the map at the spot where the sidewalk physically ends:

3.3.1.6.3.4

If there are no pedestrian overpasses or pedestrian underpasses, as well as no signs or markings on the intersections (“zebras”), the pedestrian road passes through the intersection as an extension of the sidewalk line in the following cases:

  • The roadway(s) of the intersected road has 3 traffic lanes or less.

  • The intersected road does not have a solid center line:

3.3.1.6.3.5

In places where a pedestrian road approaches a motorway, you can draw the intersection the following ways:

  • Along the pedestrian crosswalk (if there is one)

  • With no pedestrian crosswalk (if the intersecting motorway has no solid lane marker):

If the intersecting motorway has a solid lane marker, then you can draw the pedestrian road either as a separate road leading to the closest pedestrian crosswalk, or (if there is no road shoulder) you can draw it as a dead end:

3.3.1.6.3.6
If part of the road network accessible to pedestrians is isolated from the larger road network accessible to pedestrians (for example, industrial zone roads facing a street without a sidewalk and curb on one side), it is allowed to draw a pathway: a class 10 intersecting road accessible to pedestrians, which will connect the isolated section of the road network to the sidewalk.
In this case, the following conditions must be met:
  1. The pathway from the isolated section to the sidewalk does not cross a physical barrier (for example, a fence or lawn).
  2. Oncoming traffic lanes of roads with a pedestrian crossing are not divided by a median or one-way roads have three traffic lanes or less.
Examples:
  • A pathway (green line) is drawn:

  • A pathway (red line) is not drawn because it would have crossed a physical barrier ( lawn):

  • A pathway (red line) is not drawn because it would have crossed a motorway with more than three lanes:

3.3.1.6.4. Pedestrian crossing
3.3.1.6.4.1

Draw lines representing pedestrian crosswalks down the middle of the crosswalks themselves.

3.3.1.6.4.2

If the pedestrian crosswalk ends at a square that is accessible to pedestrians, then the points where the crossing ends and the entrance to the square begins are connected using segments of hypothetical pedestrian paths. Draw these paths at right angles from each other (if possible) and keep their use to a minimum.

Pedestrian roads display as yellow lines in the drawing, underground crossings — yellow dotted lines, hypothetical connecting paths — green lines:

3.3.1.6.4.3

Lines for aboveground and underground pedestrian crosswalks lead to the point where the ascent/descent begins (if the ascent/descent includes section of level ground, simplify your drawing so that there are no more than two sections):

3.3.1.6.4.4

Draw double pedestrian crosswalks (i.e. when two “zebra crossings” are located close to each other and you can only go in one direction on each of them) as a single line with the direction of traffic going both ways.

3.3.1.6.4.5

Only draw pedestrian crosswalks over railways in the following cases:

  • If the crosswalk is aboveground
  • If the crosswalk is underground
  • If the crosswalk is clearly delineated at ground level (with barriers, a surface covering)
3.3.1.6.5. Bike paths

Only draw bike paths as separate roads in cases where they are physically distinguished from the surrounding area as bike paths and road signs/markings confirm this:

In all other cases it is enough to set the Accessible to bicyclists attribute for those sections of motorway (or pedestrian) roads.

If there is unrestricted access to a bike path from a pedestrian road/sidewalk, then the pedestrian roads connected to that sidewalk must lead to the bike path (and you should not change their accessibility marking):

3.3.1.6.6

If a pedestrian road passes through the interior of a building, you should only draw the road if the building it passes through is a security checkpoint leading to a restricted area that belongs to an organization.

For example:

3.3.1.7. Rules for drawing road barriers

To make sure that automatically plotted routes don't include road sections blocked by barriers (security checkpoints, lifting gates, fences, road signs like “No entry” or “No traffic”, railway crossings, and so on) or pass through restricted territory, follow these rules for drawing road barriers:

3.3.1.7.1

Parts of the road that are set off from the road network by security checkpoints or lifting gates are drawn as separate road sections (other than checkpoints operated by the police, which are not marked with a “Restricted entry sign”). A road intersection is created at the location of a lifting gate or police security checkpoint. If the road section was created earlier, split it into two:

Add a road sign like “Restricted entry” to the intersection:

Exiting will remain unrestricted (i.e. you do not need to link the intersection with an exit restriction).

If there are multiple entrances to the territory of a business, residential complex, cottage settlement, or so on (for example, one for guests and one for service personnel), then add a Restricted entry “road sign” to all the entrances. For service entrances, you should also add a Restricted maneuver “road sign” at the same road intersection.

For example, the blue arrow marks the guest entrance on the drawing, the red arrow ─ the service entrance, and the green arrow ─ the location of the restricted maneuver sign (the same point where entry restrictions apply):

Note.

If road sections are located in a territory that is not completely restricted (not all the entrances to the territory have checkpoints or barriers), then add a Restricted entry “road sign” in both directions to the entrances with checkpoints and barriers.

3.3.1.7.2
Use the “Residential area” attribute to represent the “No traffic” and No motor vehicles signs (see section 3.3.2.15. Residential area).
3.3.1.7.3
When drawing the road network on a territory that includes checkpoints or lifting gates, assign the road section accessibility value that reflects the real-world situation. If it is technically possible to travel within the borders of the territory in question, there are no additional restrictions by vehicle type posted on road signs, and an Entrance by Permit sign was already placed at the entrance or exit, then you should not remove the vehicle accessibility attribute.
3.3.1.7.4

The "No entry" sign is set using the Restricted maneuver “road sign”. Place the "Restricted maneuver" road sign directly at the road intersection after the actual location of the sign.

Exceptions:
  • If a “No entry” sign is placed at the only entrance to an area open to locals and staff working for organizations located beyond the sign, the “Restricted entry” sign is placed at the nearest graph intersection before the sign.
  • If the only road leading inside an area is closed off with a “No entry” sign and access is only permitted for emergency vehicles, the road should be marked as accessible only to pedestrians and bicycles, and its class should be set as “Pedestrian and bike paths” (class 10).

If there is a roadblock, the road should be split (e.g. a drive-through has been closed off by a concrete block or gates that go unused by either passers-by, staff, tenants, or corporate vehicles). Two road signs of the “Prohibited maneuver” type are linked to the intersection to prevent passage through the barrier in both directions:

When the road network is drawn this way, it does noes not split at the location of the barrier, though no routes can be plotted that intersect with the barrier.

If a road section can't be accessed by car due to obstacles installed on both sides of the road (for example, concrete blocks at the beginning and end of the section), then set the class of this section to 10 (Pedestrian and bike paths) but don't mark it with the “Prohibited maneuver” road sign.

Attention.

When drawing a permanent obstacle on the road, split the section of the road graph where the obstacle is.

Do not use an already existing graph intersection to create a prohibited maneuver of this type.

Correct Incorrect
3.3.1.7.4.1

If passage is prohibited by traffic regulations (markings or road signs) but special documents (passes) allow some vehicles (or a specific car) to ignore the ban, the traffic condition is set as Prohibited maneuver and not as Restricted entry (see 3.3.1.7.4).

3.3.1.7.5

When drawing a road that intersects with a railroad crossing, draw a “Railway crossing” at the intersection (see Section 3.8.6. Railway crossings).

3.3.1.8. Rules for drawing seasonal roads

Seasonal roads include ferry and ice crossings, and winter roads.

Due to the complete or partial absence of seasonal roads in satellite images, they are drawn using GPS tracks and official information confirming their existence and indicating the point of departure and destination.

3.3.1.8.1
Ferry crossings are assigned the “ferry crossing” value for the Type of structure attribute. For ice crossings and winter roads, this attribute is left blank (its value is set to “No”).
3.3.1.8.2

For named seasonal roads, an “official” name can be indicated. Tthe name is not assigned “for the map caption”. See 3.3.3.3.3.4. Highways without a number, but with a proper name.

3.3.1.8.3

Ice crossings that are set up in place of or in the immediate vicinity of a ferry crossing (providing that their start and end points coincide with those points of the ferry crossing) are created by editing the attributes of the existing road sections.

Don't delete the ferry crossing from the map. All edits should be made to the existing road sections.

3.3.1.8.4

Don't draw pedestrian paths that are formed and available only in winter.

For example, ski trails and paths that pass through reservoirs.