An '''alternate route''' is an alternative to a detour or possible detour. It begins immediately after the last segment before the '''possible detour''' and ends immediately before the first segment after the Possible Detour. If it meets the criteria below for '''direct route, '''the alternate route is also a direct route.
ul><li>'''Segments before and after the possible detour:''' The freeway/highway segments immediately before and immediately after the possible detour must share at least one street name among their primary and alternate names. Either segment may have the shared name as either a primary or an alternate name.</li>
<li>'''Confirmed detour:''' A confirmed detour is a a possible detour that meets all of these criteria:
decimal;"><li>'''Name discontinuity - '''The possible detour must have at least one break in name continuity from the last segment before the detour to the first segment after the detour. Specifically, the last segment of the possible detour must not have name continuity with the first segment after the possible detour.</li>
<li>'''Road type discontinuity''' - The freeway/highway segments immediately before and immediately after the possible detour must be from the same '''road type group''' as shown in the table below. The possible detour must include at least one segment not in that same '''road type group'''.</li>
<li>'''Minimum length''' - The possible detour must be more than one segment long.</li>
<li>'''Direct route:''' A direct route is an alternate route that meets the criteria below:
<ol><li>'''Existence''': There must be an alternate route connecting the freeway/highway segments immediately before and immediately after the detour which does not use any of the segments used in the possible detour.</li><li>'''Continuity''' The entire alternate route should have name and road type continuity. In the past, less resource-intensive methods have been used for checking the direct route. Currently, a full continuity check is in use.
<ol style="list-style-type: lower-alpha;"> <li>'''Full continuity''' - All segments of the Alternate route must have both name and type continuity with the segment immediately before and the segment immediately after the possible detour - the most resource-intensive continuity check. </li> </ol></li></ol>