Consuming the traffic service using ArcMap

After connecting ArcGIS for Desktop to traffic.arcgis.com, which is one of the servers providing ArcGIS Online network analysis services, you can begin viewing traffic and traffic incidents in ArcMap.

Viewing the traffic layer in a map

Steps:

1. Add a basemap or other reference data to ArcMap and zoom in to your area of interest, such as a metropolitan area.
2. Click the Catalog Window button on the Standard toolbar to open the Catalog window.
3. Expand GIS Servers > arcgis on traffic.arcgis.com > World.
4. Drag Traffic from the Catalog window and drop it on the map or the Table of Contents window.

   In most cases, traffic and traffic incidents will draw on the map. If you don't see either one, read the subsequent section of this topic to understand why they may not be drawing.

Traffic drawing behavior

This section describes how the traffic layer's drawing behavior changes as you navigate the map and change settings in ArcMap. This will help you understand what you're seeing and know what drawing behavior to expect so that you can get the traffic information you need.

Map scales

You might not see traffic even when the World/Traffic layer is checked in the table of contents. The following conditions also need to be met:

• The map extent you are viewing covers a region where traffic data is available. See what regions provide traffic data.

  Although most countries with traffic data have extensive data coverage within their borders, some countries have limited coverage. You may need to pan to find an area with traffic data.

• The map scale is zoomed in beyond 1:10,000,000.

  The actual scale at which traffic and traffic incidents begin to draw depends on the region, but all regions with traffic begin drawing when zoomed in beyond 1:10,000,000. Only primary roads draw at this scale, so zooming in closer is required to see traffic on lower-order roads.

As you zoom in closer, traffic data from major roads, then local roads, are revealed. You will also notice as you zoom in beyond a certain scale, traffic for primary highways is offset so you can clearly see traffic conditions for both directions of travel.

Traffic incidents are also divided into groups and revealed at different scales. The more severe incidents are drawn at smaller scales. As you zoom in to larger scales, less-severe incidents are drawn with the severe incidents.

Time

Traffic is dynamic and changes with time. By default, time is disabled on the map, and the traffic layer displays current traffic conditions when time is disabled.

To see historical or predicted traffic conditions, enable time on the map, then use the time slider to set a time and date. The steps below show in detail how to do this.

Steps:

1. Enable time on the World/Traffic layer.
   1. Right-click the layer and choose Properties.
   2. Click the Time tab.
   3. Check Enable time on this layer.
   4. Click OK.
2. Click the Time Slider button , which is on the Tools toolbar, to open the time slider. Time on the map is automatically enabled.
3. Set the time zone property on the Time Slider dialog box to match that of the area you are viewing.
   1. Click the Options button .

      The Time Slider Options dialog box opens.

   2. Click the Time Display tab.
   3. For Time zone, choose the time zone that you want the time and date in the Time Slider dialog box to represent.
   4. Check Adjust for daylight saving changes.
   5. Click OK.
4. Set the time slider to the time and date for which you want to visualize traffic conditions. You can type the time and date into the text box or slide the pointer to the appropriate position.

   Caution:

   The time and date you enter are specific to the time zone set in the Time Slider Options dialog box. This can be misleading if the time slider is set to one time zone and the map is zoomed in to an area that is in a different time zone.

   For example, say the time zone on the Time Slider Options dialog box is set to Eastern Standard Time and you are looking at traffic in Los Angeles (Pacific Standard Time), which is three hours behind EST. If you move the time slider to 8:00 a.m., the map shows traffic conditions in Los Angeles at 5:00 a.m. PST.

   To show traffic at 8:00 a.m. PST, you can either offset the time slider yourself to adjust for the time difference (enter 11:00 a.m.), or you can change the time zone in the Time Slider Options dialog box to match the area you are viewing in ArcMap. In most cases, it makes sense to change the time zone.

5. To show traffic for the current time again, you can set the time slider to the present date and time, such as by clicking the Live Mode button on the Time Slider dialog box, or by disabling time on the map. To disable time, click the Disable time on map button .

   The recommended way to see live traffic is to disable time on the map since time zones are completely ignored in that situation. In live mode, however, the time slider may reference a different time zone than the one you are in, and this can cause confusion.

Live and predictive traffic takes precedence over historical traffic

The traffic service provides three kinds of traffic: historical, live, and predictive.

Historical traffic is based on averages and is good for providing an estimate of what traffic would look like for a given time of the day and day of the week. To create historical traffic data for the service, a week is broken into hundreds of five-minute intervals, travel speeds are collected for each interval over several weeks, then the speeds for each interval are averaged. The result is a potentially different travel speed on a road for each five-minute range in a week.

Live traffic is a measure of current travel speeds, which come from sensors along the roads, cell phones, and other sources. There is a slight lag—sometimes up to 15 minutes—from the time the speeds are collected to the time they are processed and delivered through the traffic service. Once processed, the traffic record of actual speeds are available for 12 hours in the past. Setting the time slider to more than 12 hours prior causes the layer to render historical traffic.

Predictive traffic takes live traffic as well as other information, including weather, events, holidays, and historical traffic, to make travel-speed forecasts. Currently, predictive traffic spans 12 hours into the future, but this is subject to increase as prediction methods improve. After the 12 hours, the traffic reverts back to drawing historical traffic data.

More streets are covered by historical traffic data than live and predicted. When viewing traffic within the time range when live and predictive traffic are available, you can see more traffic by filling in with historical traffic. This is the default drawing behavior. You may want to see live and predicted traffic only, however. To do this for North America, expand the following layers in the Table of Contents window: World/Traffic > North America > North America Traffic. Uncheck Traffic and check Live Traffic.

The process of visualizing only live and predictive traffic for the other regions listed in the World/Traffic layer is similar. Note that the layer won't show any traffic if you set the time slider to a time outside the 12-hour prediction depth or the 12-hour, live-traffic archive.

To view a blend of historical, live, and predictive traffic again, uncheck Live Traffic and check the Traffic layer.