Starting on Monday, carpool drivers taking the Golden Gate Bridge into the city not only will have to pay $3, but they will have to flash a FasTrak or pay $5. Up until Monday, carpoolers could use cash to pay the toll. Now it’s electronic or else.

It is part of increased tolls on bridges that went into effect recently. The GGB began charging carpoolers on May 28, and on July 1, the Bay Bridge slapped a $2.50 toll on formerly free carpoolers.

But on the Marin to San Francisco span, carpoolers must go through a staffed toll lane so that an agent can verify that the car contains three or more passengers. If you drive through the FasTrak lane, no matter how many are in the vehicle, you’ll be charged $5. Consider it fair warning, Marin.