Spending millions of dollars for bicycle bridges is great, but here’s what would really lure people to leave their cars at home and bike to work:

A shower.

A place to peel off your sweaty gear, grab a bar of soap, rinse off the grime from a long bike ride — and avoid making your co-workers hold their noses and wish you were in a cubicle far, far away.

“Showers are absolutely at the top of the list” of bicycle commuters’ needs, said Jake Olsen, who bikes 12 miles a day to his job as a process engineer manager at Apieron, a medical-device startup in Menlo Park. “We have only one rather bedraggled shower and only two lockers for almost 35 men.”

Thursday is the 15th annual Bike to Work Day, an event for which thousands pedal to their jobs. More than 300,000 bicycle trips are made every weekday by Bay Area residents, and 81,000 are commute trips.

For an increasing number, bicycling has become a daily ritual. But for many, Bike to Work Day is a one-day fun ride, then it’s back into the car the next day.

In a Roadshow survey of cyclists’ biggest needs, showers were by far the No. 1 suggestion, followed by a safe place to store bikes and an alternative way home in case of emergency.

Amy King of San Jose used to bike to work when she taught elementary school in Marin County. She would shower before taking off in the morning, then reach for a box of baby wipes and some antiperspirant after arriving at school. That, she hopes, got the job done.

“No one,” she claims, “ever complained of me being stinky. At least not to my face.”

The Silicon Valley Bicycle Coalition says secure bicycle storage, showers and on-site bicycle maintenance materials and facilities rank 1-2-3 on its priority list.

“It is really the little things that make all the difference,” said Sean Co, a planner with the Metropolitan Transportation Commission. “Lack of parking can be a huge detriment to bringing your bike to work. Bike theft is unfortunately common and people don’t want their bike stolen.”

He has that right, said John Walker, who bicycles 18 miles from Curtner Avenue in San Jose to Google in Mountain View.

“Nobody is going to commute by bike if they feel their bike may not be around at the end of the day,” said Walker, 44, a software engineer. “When I commute, my bike lives in a wide hallway near my desk. Lots of bikes at Google live in unoccupied cubicles or under stairways.”

A growing number of companies and cities are adopting bike-friendly policies. Since 2001, San Jose has required large new commercial development to include showers in building plans. Ditto San Francisco, Berkeley, Oakland, Alameda and San Leandro. Sunnyvale insists on one secured bicycle parking space for every four units in housing developments.

Cupertino, Santa Clara and Campbell all urge developers to add showers and bike storage.

And, as of Jan. 1, bicyclists nationwide can receive up to $20 a month in pretax dollars from their employers if they commute primarily by bike and don’t accept any other transit benefits.

Almost all bicyclists say a relaxed attitude by their employer is a big plus. San Jose City Councilman Sam Liccardo says companies that allow employees to “dress down” boost bicycling.

And Norm Picker of East Palo Alto says bosses who avoid late afternoon meetings in the winter help bicyclists avoid commuting in the dark.

Olsen is just thankful his startup has one shower, even if it needs more. He is one of the few who bikes to work at his company and usually gets first dibs at cleaning up.

“It would be gamy indeed if we have four or five guys biking in,” he said. “You’d probably have some stinky clothes lying around the cube.”

Is a place to shower enough to get you out of your car and onto a bike? Let Gary Richards know at mrroadshow@mercurynews.com or 408-920-5335.