MOUNTAIN VIEW, Calif. — The perks of working at Google are the envy of Silicon Valley. Unlimited amounts of free chef-prepared food at all times of day. A climbing wall, a volleyball court and two lap pools. On-site car washes, oil changes and haircuts, not to mention free doctor checkups.

Not that small, really. The shuttles, which carry up to 37 passengers each and display no sign suggesting they carry Googlers, have become a fixture of local freeways. They run 132 trips every day to some 40 pickup and drop-off locations in more than a dozen cities, crisscrossing six counties in the San Francisco Bay Area and logging some 4,400 miles.

They pick up workers as far away as Concord, 54 miles northeast of the Googleplex, as the company’s sprawling Mountain View headquarters are known, and Santa Cruz, 38 miles to the south. The system’s routes cover in excess of 230 miles of freeways, more than twice the extent of the region’s BART commuter train system, which has 104 miles of tracks.

Morning service starts on some routes at 5:05 a.m. — sometimes carrying those Google chefs — and the last pickup is at 10:40 a.m. Evening service runs from 3:40 p.m. to 10:05 p.m. During peak times, pickups can be as frequent as every 15 minutes.

At Google headquarters, a small team of transportation specialists monitors regional traffic patterns, maps out the residences of new hires and plots new routes — sometimes as many as 10 in a three-month period — to keep up with ever surging demand.

Many employers run programs for commuters, including van pools, shuttles to and from transit hubs and subsidies for public transit and alternative modes of transportation, but several transportation experts say Google appears to have built an unparalleled transit network.