Available with Business Analyst license.
Overview
Trade Areas of equal travel time or travel distance can be created by generating Drive Time polygons within Business Analyst.
Complete and up to date street networks with associated traffic volume by time of day, day of week, and date are used to create Drive Time Polygons.
Drive Times would be the appropriate Trade Area option if travel time or distance outweigh consistent area (simple rings) or equitable share of customers (equal competition) across Trade Areas.
Travel modes
Select your travel mode using the Travel mode drop-down menu. You can choose from:
- Driving time - Models the movement of cars and other similar small automobiles, such as pickup trucks, and finds solutions that optimize travel time. Travel obeys one-way roads, avoids illegal turns, and follows other rules that are specific to cars. Dynamic travel speeds based on traffic are used where it is available when you specify a start time. Driving Distance is an option.
- Rural Driving Time - Models the movement of cars and other similar small automobiles, such as pickup trucks, and finds solutions that optimize travel time. Travel obeys one-way roads, avoids illegal turns, and follows other rules that are specific to cars, but does not discourage travel on unpaved roads. Dynamic travel speeds based on traffic are used where it is available when you specify a start time. Rural Driving Distance is an option.
- Trucking Time - Models basic truck travel by preferring designated truck routes and finds solutions that optimize travel time. Routes must obey one-way roads, avoid illegal turns, and so on. Trucking Distance is an option.
- Walking Time - Follows paths and roads that allow pedestrian traffic and finds solutions that optimize travel time. The walking speed is set to 3 miles per hour. Walking Distance is an option.
Input prerequisites
To run a drive-time trade area, any point location and routing service is required.
To select Travel mode you must be signed in to your ArcGIS Online account
These input layers can be identified and selected in the Trade Area Wizard while creating Drive Times.
The routing service NAVTEQ_NA_ND is provided as part of the Business Analyst installation and is found at C:\ArcGIS\Business Analyst\US_2016\Data\Streets Data\NAVTEQ_2016_Q1_NA.gdb\streets\. Set this service by clicking Preferences > Dataset tab > Street Network.
Preferences
The following Drive Time Trade Area parameters can be customized by navigating to the Business Analyst Menu, selecting Preferences and then the Drive Time tab:
Direction
Distance and time travelled along a road can vary significantly based on direction.
To ensure accurate Drive Time Trade Areas are generated, Direction of travel can be specified as either towards or away from facility (Drive Time starting point).
An example of when direction of travel would be Towards Facility would be customers driving to a store.
Alternatively, if interested in travel time of a mail carrier leaving the facility to deliver to various customers, it would likely be appropriate to select travel Away From Facility.
Time of Day Options
Since traffic volume fluctuates by time, day, and date, these three parameters can (optionally) be specified by clicking the Time of Day button, and checking the Use Time of Day box. Doing so will activate the Time of Day, Day of Week, and Specific Date fields.
Entering this optional information helps to ensure that generated drive times are both accurate and relevant to your analysis.
Restrictions
Travel time is impacted by mode of transportation, types of roads we use or avoid, and preferred routes.
Business Analyst includes over 30 optional restrictions, such as Walking, Avoid Toll Roads and Driving a Bus.
Choosing restrictions mirroring the real world activity being modeled further refines the resulting Drive Time Trade Area(s).
Drive-Time Algorithm
Three drive-time algorithms are provided as part of the Business Analyst installation:
- 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. Expect detailed polygons to take noticeably longer to generate than generalized polygons.
- ArcGIS Online API - This algorithm uses the hierarchy of a network dataset as it solves. Generalized polygons are generated quickly and are fairly accurate, except in the fringes.
Snapping Tolerance Options
Occasionally, a drive time starting point does not fall along a road network. This is often the case in newer commercial developments without streets or when a point is geocoded to a remote rooftop away from a road.
These situations can be resolved through the use of three Snapping Tolerance Options.
Setting the Maximum Snapping Tolerance parameter indicates how far, in the chosen distance units, the system should look for a nearest road, which will be used as the initiation point of the Drive Time.
If the nearest road falls outside of the specified distance then no drive time polygon will be generated.
The Minimum Snapping Tolerance indicates how far from the starting point, in chosen distance units, the system should begin looking for a nearest road. It is common to leave this setting at 0.
Further control and flexibility over the output is provided via the many options to choose from when setting Tolerance Distance units.
Example output
The image below shows drive-time areas that are created around a starting location represented by the red star. The yellow polygon represents the area around a location that one can reach within 3 minutes. The red represents a 5 minute threshold. The area in the 5 minute threshold in the blue box is a hole in the drive time. Drive times can have holes depending on road segment types, one-way streets, natural barriers (mountain with no roads, for example) etc.
Learn more about Drive-time Areas.