Update Costs – Turn Category Settings

The Turn category settings define how long the delay in seconds is to make different types of turn, for example: left, right, U-turn. This will also depend on the nature of the links being turned from and to, for example, a right turn from a local road to a primary road is likely to take longer than a left turn from a primary road into a local road (assuming driving on the left as in the UK).

Turn category costs

Note that the Esri tutorial is US-based so puts a greater delay on turning left than right, whereas it is the opposite for the UK.

Now that a hierarchy has been established, there will be more turn categories available (one for every combination of hierarchy levels).

The Turn Category evaluator (accessed from the 'Turns' section at the bottom of each of the Cost set-up screens) enables the user to define the delay in seconds for each type of turn as well as setting the azimuth angle that defines a turn vs. straight-ahead vs. reverse.

The approach described in the Esri tutorial was followed, except for swapping right for left as per the above. All other turn category settings, such as turn azimuth range and road classes were left at their defaults. These are visualised in the screenshot below.

Updated Turn Category settings following the introduction of a road hierarchy.