The Transbay Joint Powers Authority, after closing its recently dedicated Salesforce Transit Center, is investigating the cause of cracked built-up plate girders supporting the roof garden.

A diminutive bus station on Minnesota’s Highway 61, just southeast of St. Paul, is the first step in a much larger redevelopment project.

An old Chicago station serving 1.8 million subway and bus riders each year is soon to receive a $15 million makeover.

With a billowing, veil-like facade and generous skylights, a large new transportation hub in San Francisco will replace a shabby station from the 1930s.

Nearly 90 years after it was first proposed, a 2-mile stretch of subway connects Manhattan’s Upper East Side to Midtown.

Two of New York City’s most overburdened transportation facilities— Pennsylvania Station and the Port Authority Bus Terminal, which together serve nearly a million passengers a day —could be dramatically upgraded or replaced if proposals developed by architectsand recently made public are adopted.