Friday, May 22, 2009
The Google Maps driving and walking directions team has traditionally been in the business of answering the question "what is the best way to get from point A to point B?" When there's a single obvious route, we usually don't have a problem finding it. When there are many good routes to your destination, we suggest one we consider to be the best and let you drag the route around to discover the rest. But what about when there are two or three different routes that all get you to point B effectively? Wouldn't you like to see them all on the map for comparison? Now you can!
When there is more than one good way to get from A to B, we still show you the route we think is best, but in addition we now show one or two additional routes, under the "Suggested Routes" heading. These are other good routes that we think you might be interested in because they are different enough from the best route that personal preferences are likely to affect your choice.
For example, when driving between the two engineering offices in Washington, while we still return the WA-520 bridge as the primary route, we offer the additional suggestion of the I-90 bridge which you might prefer because it has carpool lanes; hover over a suggestion to see both routes on the map, and click on a suggestion to update the step-by-step directions:
For those curious about what's happening behind the scenes, here are some slightly technical details. Deciding which route is "best" involves balancing competing factors: distance, travel time, number of turns, and many more. We boil all these factors down to a "cost" associated with each candidate route and display the route with the lowest "cost." But we don't know about all of your personal preferences, some of which can mean a higher cost route is better for you. Now you can compare and choose!
One final tip: when you're evaluating routes, check to see if the traffic layer is available in your area so you can see either the live conditions or the predicted conditions for when you're traveling, helping you make a smart decision about the best route for you.