Driving home after work? Please think twice about leaving during the afternoon peak commute hour - 5 to 6 p.m.

Stanford is committed to limiting the number of cars that enter and exit campus during commute hours. While the university has achieved its goal in the morning with a comfortable margin, curbing the number in the afternoon has proved more challenging.

L.A. Cicero Cars on campus

Academic and administrative departments are asked to offer employees work hours that help them avoid driving during peak commute times.

Over the years, Stanford has devised various enticements to get employees who commute to work to leave their cars at home.

There are the tiny stickers: the shiny GO Pass for Caltrain and the crayon-colored ECO Pass for Santa Clara Valley Transportation Authority bus, express bus and light rail trips.

There is the Commute Club, which pays people "clean air cash" and other benefits for belonging to the group.

There is the colorful fleet of Zipcars: the self-service, on-demand, car-sharing program that offers special rates for the Stanford community. Thirty-eight cars are available at 14 campus locations and two off-campus sites on California Avenue and Porter Drive.

"Our program is set up primarily to be carrots," said Brodie Hamilton, director of Parking & Transportation Services at Stanford. "The one stick in the program is the fee for a parking permit," he said, referring to the university's commuter parking program.

Stanford celebrated a major milestone last June when an annual survey showed that 52 percent of employees on the main campus walked, biked, shared rides or used public transportation instead of driving solo in 2010, up from 28 percent in 2002.

Still, with staff turnover and legions of employees yet to be convinced, Hamilton and his staff aren't resting on their laurels.

One of the reasons why is Stanford's General Use Permit, which was approved by the Santa Clara County Board of Supervisors in 2000. The permit placed conditions on the university's land use, growth and development. Stanford agreed to comply with the conditions in order to win approval to develop campus land.

Keeping commute trips below 2001 levels is a university goal 

Under the permit, commonly known as "GUP," Stanford agreed to keep the number of vehicles that entered and exited campus during peak commute hours below the number recorded in 2001.

To help meet that goal, Stanford launched its Transportation Demand Management program, which in turn created dozens of programs to entice commuters to walk, bike, carpool, vanpool or take the bus or train to work.

Stanford could have taken a different approach, paying for traffic mitigation measures rather than investing in employee commute programs. Instead, the university chose to limit the number of commute trips, recognizing that it was better for the environment, better for employees and better for the community. 

"By keeping the number of cars arriving and leaving campus below 2001 levels, we were helping to reduce the carbon dioxide emissions that contribute to global warming, improving air quality and helping to reduce traffic in our surrounding communities," Hamilton said.

"And, in what turned out to be another big benefit, Stanford didn't have to build all the parking spaces we originally thought we would need on campus."

And of course there are the personal health benefits of walking or biking and the stress reduction that comes with not sitting in traffic, he said.

Keeping track of cars coming and going during peak periods

The county does a "cordon count" every fall and spring, recording the number of vehicles that enter and exit campus at 16 locations.

In recent years, Stanford has achieved its goal during morning commute hour of 8 to 9 a.m., staying several hundred cars below the baseline number of 3,400 cars.

Curbing the number of cars leaving campus in the afternoon has proved more challenging. While Stanford has kept the total below the 2001 total – 3,600 – each year, the number has been a little too close for comfort for Hamilton.

Since 2001, the afternoon total has averaged about 100 cars under the baseline. In 2004, the afternoon total was 15 trips below the baseline, which is one reason the program uses "every trip counts" as its tagline.

Hamilton described the 5 to 6 p.m. commute hour as "the most crucial hour" for drivers to be aware of when leaving campus.

If Stanford exceeds the baseline in two out of three consecutive years, the university would have to share the cost of revamping 15 intersections in the area to improve traffic flow, he said.

Ways for everyone to participate

"We acknowledge that everybody can't use alternative transportation, so the next best thing is to do it part time," Hamilton said. "Can you take the train once or twice a week? Even that would help in terms of the traffic count and traffic congestion. It doesn't have to be all or nothing.

"If you can't use alternative transportation at all, please try to plan your commute so you're not driving into campus between 8 and 9 in the morning or leaving between 5 and 6 at night," he said. "Essentially, there's a way for everyone to participate and help Stanford reach its goal."

Hamilton said academic and administrative departments could help by offering employees work hours that help avoid the peak commute times and by scheduling meetings and events so they don't coincide with the morning and afternoon rush hours.

"It's not just, 'hey employees, it's all up to you,'" he said. "We're looking to the deans and the administrative unit heads to actively participate. This is a university effort."

Departments can also help employees by signing up for free Zipcar accounts, which offer discounted hourly rates to Stanford members.

"People who usually take the train or bike to work don't need to bring a car to campus on the days they need to drive for business purposes if their department has a Zipcar account," Hamilton said. "Instead, they can use Zipcars and charge their department directly for the hourly rates. It's very convenient."