San Diego-area transit officials on Friday will step up bus and trolley service on the coast to help Fourth of July celebrants get around.

It is also staging a special promotion for the holiday – riders who pay a regular fare or use a pass can bring along a friend at no extra charge.

Five bus routes operated by the Metropolitan Transit System – 8, 9, 27, 30 and 901 – will include more frequent runs as they pass through Mission Beach, Pacific Beach, La Jolla and Coronado.

Other bus routes will operate Friday on a Sunday schedule.

The San Diego Trolley will also run on a less-frequent Sunday schedule, although MTS will add extra trips late in the evening for those watching fireworks.

More information is available at www.sdmts.com.