Available with Location Referencing license.
Route concurrency occurs in a roadway when two or more routes share a section of pavement. This is a familiar scenario to motorists for whom concurrent road signs are a common sight indicating a roadway section has more than one route.
Concurrent routes provide some challenges to an LRS Editor, since events reference sections rather than route designations. Events along a concurrent route section are associated with only one route, so route loading and route editing can impact associated events.
If a segment of a concurrent route is retired or realigned, the existing event records on that segment may be assigned to another concurrent route (depending on the event behavior assigned to the event layer). By configuring route dominance rules, we can provide a set of rules to decide which of these routes is the new parent route for an event after an edit has taken place.
The need to have events locate on a dominant route in a concurrent section is managed by applying rules that decide the dominant route in a section. Dominance rules are based on fields in an LRS Event table or feature class, or in the LRS Network itself, that can be compared to order concurrent routes.
In ArcGIS Roads and Highways, concurrent routes share the same centerline feature, but are modeled with different measures that belong to the route.
Route dominance scenario
The following scenario demonstrates the use of route dominance rules to find the dominant routes on concurrent sections.
The above diagram shows a roadway on which multiple concurrent sections (2,3,4,..8) exist. Each route has a functional class and name, whereas some of the routes have a number associated with them.
The following table identifies the concurrent sections in the above diagram:
| Section | Concurrent routes |
|---|---|
| 2 | R1, R2 |
| 3 | R1, R2, R3 |
| 4 | R1, R3 |
| 5 | R1, R3, R4 |
| 6 | R1, R4 |
| 7 | R1, R4, R5 |
| 8 | R4, R5 |
The following table shows the Functional Class values used in this scenario:
| Code | Functional Class |
|---|---|
1 | Interstates |
3 | Principal arterials |
6 | Local roads |
The following table shows the route numbers, their Functional Class, the numeric portion of the route ID, and the route name:
| Route ID | Functional Class | Number | Name |
|---|---|---|---|
R1 | 6 | Stuart Ave | |
R2 | 1 | 15 | I15 |
R3 | 1 | 10 | I10 |
R4 | 3 | 89 | US89 |
R5 | 3 | 110 | US110 |
Note:
- Concurrent routes in a section share a SectionId in each concurrent group.
- The network feature class or any nonspanning line event that is registered to the Network can be used to calculate concurrencies.
- The exceptions can be listed separated by a comma.
- Multiple attribute fields can be used to create a rule.
- Multiple rules can be used to decide the dominance.
Here is the workflow for the application of rules:
In this example, two rules are used to find the dominant route:
| Rule | Fields | Order Method | Order Type | Exceptions |
|---|---|---|---|---|
Rule1 | Functional Class | Lesser | Numeric | |
Rule 2 | Number | Lesser | Numeric | 110 |
The dominant route in a concurrent section gets the Dominant Flag value of 1, the non-dominant routes get a value of 0. The Dominant Error column has the following five potential values.
| Dominant Error | Description |
|---|---|
0 | No error when calculating the dominant route in the concurrent section. |
1 | Two or more routes have the same attribute value for the concurrent section. The dominant route was randomly selected. |
2 | Null or no values were present for the attribute, or attributes, used to calculate the dominant route in the concurrent section. |
3 | Too many values were present for the attribute, or attributes, used to calculate the dominant route in the concurrent section. |
4 | One of two conditions are present in the concurrent section: the route is not calibrated in the concurrent section or the centerline that composes the concurrent section doesn't align with the geometry of the route. |
Here is the result after calculating the route dominance using the rules provided above:
| Section ID | RouteID | Dominance Flag | Dominance Error | Details |
|---|---|---|---|---|
| 2 | R1 | 0 | 0 | |
| 2 | R2 | 1 | 0 | The functional class value of this route is lesser than that of route R1, so this route is the dominant route using Rule1. |
| 3 | R1 | 0 | 0 | |
| 3 | R2 | 0 | 0 | |
| 3 | R3 | 1 | 0 | The functional class value of this route is lesser than that of route R1 and the same as that of route R2. Since there is a tie between R3 and R2 using Rule1, we’ll use Rule 2 where the value of the Number field for R3 is lesser than that of R2. |
| 4 | R1 | 0 | 0 | |
| 4 | R3 | 1 | 0 | The functional class value of this route is lesser than that of route R1, so this route is the dominant route using Rule1. |
| 5 | R1 | 0 | 0 | |
| 5 | R3 | 1 | 0 | The functional class value of this route is lesser than that of route R1 and R4, so this route is the dominant route using Rule1. |
| 5 | R4 | 0 | 0 | |
| 6 | R1 | 0 | 0 | |
| 6 | R4 | 1 | 0 | The functional class value of this route is lesser than that of route R1 and R4, so this route is the dominant route using Rule1. |
| 7 | R1 | 0 | 0 | |
| 7 | R4 | 1 | 0 | The functional class value of this route is lesser than that of route R1 and same as that of R2. Since there is a tie between R3 and R2 using Rule1, we’ll use Rule 2 where the value of the Number field for R3 is lesser than that of R2. |
| 7 | R5 | 0 | 0 | |
| 8 | R4 | 0 | 0 | |
| 8 | R5 | 1 | 0 | The functional class value of this route is the same as that of R4. Since there is a tie between R3 and R2 using Rule1, we’ll use Rule 2 where 110 is listed as an exception, thus making R5 the dominant route. |
Note:
Alternatively, more than one field can be used for creating a rule:
| Rule | Fields | Order Method | Order Type | Exceptions |
|---|---|---|---|---|
Rule1 | Functional Class, Number | Lesser | Numeric | US110 |
In which case, the concatenated value of the two fields in the order they appear in the list is used to calculate the dominance.