Boston has the third longest average commute time among major U.S. cities, with only 13 percent of commuters able to reach their destinations by vehicle or mass transit within 30 minutes.

That is according to a new report from connected vehicle company Geotab, which analyzed census data for the largest cities in the nation’s 20 largest metropolitan areas (which, of course, includes the Boston area).

The report comes on the heels of a MassINC poll that showed that more than one-fifth of full-time workers living within Route 128 has considered moving away from the Boston area because of long commutes. The Geotab analysis also follows other reports showing similarly long slogs for regional and local commuters.

Specifically, Boston is tied with New York for second-worst city for commuting via car among the major cities analyzed, with an average of 40 minutes each way. The map immediately below spells that out.

As for mass transit, including the T, the situation is not much easier for commuters (see the map immediately above). The average length is 49 minutes each way, according to the analysis. That makes Boston the fourth-worst nationwide for commuting via mass transit, behind only New York, Chicago, and Washington.

All of this translates into a Boston proper that is not easily “reachable” for commuters, as the Geotab analysis puts it. That is, it takes relatively forever to get to and from the core. Only 13 percent of commuters can reach it within 30 minutes—and just 8 percent can do so by public transit.

As for the most reachable major cities in the U.S., those include San Diego, Phoenix, and Minneapolis. But these towns are particularly easy to get in and out of by car alone, not mass transit, according to the report.