Drive time tab

Use the Drive time tab to select the speed limits template, speed units to display, drive time algorithm and snap tolerance options.

Steps:

1. To set the speed limit options, click the Speed Limits template drop-down menu to choose the speed limits template and set the speed limit options. You can choose from the predefined Normal, Rush Hour or Light templates or modify the values to create a custom template.

   Modifying any of the values in either Light, Normal, or Rush Hour will automatically create a Custom speed limits table.

2. To set speed unit display options, click the Speed Units to Display drop-down menu to set speed units. Choose between MPH and KPH.
3. Choose the drive-time algorithm. You can choose from Standard Drive Times (Fastest) or Detailed Drive Times. Both are from the ArcGIS Network Analyst extension. This globally sets the type of drive time algorithm in an applicable wizard such as drive time trade areas or threshold area trade area drive time rings. Analyses such as desire lines or the locator report aren't affected by this setting because they don't use the OD-Cost matrix from ArcGIS Network Analyst extension. ArcGIS Network Analyst extension can only be used for certain analyses.
   • Standard Drive Times (Fastest) - This algorithm uses the hierarchy of a network dataset as it solves. This diminishes the number of roads that must be searched in the solve process and therefore makes solving a service area layer much faster. Generalized polygons are generated quickly and are fairly accurate, except in the fringes. The generalizing of polygons may result in islands of unreached elements being covered.
   • Detailed Drive Times - This algorithm uses the network dataset without a hierarchy. Detailed polygons model the service areas more accurately and thus may result in islands of unreached areas. Expect detailed polygons to take noticeably longer to generate than generalized polygons.

   If generating drive time areas in an urban area with a gridlike network, the difference between generalized and detailed polygons would be minimal. However, for mountain and rural roads, the detailed polygons may present significantly more accurate results than generalized polygons.
4. Modify your street network snap tolerances if necessary. Set your minimum and maximum distance where a point snaps to a road segment. For example, if a site prospecting point is placed near a new development without existing roads, the point will snap to the nearest street segment within the selected tolerance to begin an analysis.
5. Click OK to save your preferences or click a different tab to set other preferences.