Robertson isn't among the legions of newly minted freelance drivers cruising the streets in their own cars for upstart ride services Lyft, Sidecar or UberX.
He's a nine-year veteran of venerable Luxor Cab using a taxi-hailing app called Flywheel from a Redwood City company of the same name.
Flywheel, now in two-thirds of San Francisco cabs, may be the beleaguered taxi industry's best bet to compete against the tech-enabled newcomers.
"Flywheel will help us level the playing field," Robertson said. "It's exactly the same (as the rivals' services) in all the ways that count, but without the issues."
Those issues - insurance coverage, car inspections, driver training - are hammered home by taxi drivers fearful of losing their livelihood to new rivals that operate with fewer regulations.
"In San Francisco the taxi fleets understand that they need to modernize to survive," said Flywheel CEO Steve Humphreys, a Stanford-trained engineer and serial entrepreneur.
Flywheel's secret weapon is centralized dispatch. Instead of passengers calling a specific company and being limited to its available cabs, the app finds the nearest cab among all participating drivers regardless of taxi company.
"An app that orders a cab from (almost) every cab company in the city will fix the problem where riders call multiple cab companies because they're so impatient they can't wait," said Trevor Johnson, a Luxor driver.
Flywheel won't disclose specific numbers except to say the business is generating double-digit growth week over week. In June, the company said it was handling 16,000 San Francisco rides a month.
A few drivers said it provides about 10 to 15 percent of their fares. Yelp has only 10 reviews for Flywheel in San Francisco compared with more than 300 for Uber and more than 130 for Lyft.
But unlike a lot of startups, Flywheel generates revenue from the get-go. It takes 10 percent of the metered fare from drivers plus a $1 surcharge from passengers.
Predated new rivals
Humphreys started the company, then called Cabulous, in 2009 with a simple vision: "to get people around cities quickly and more easily, simply by utilizing the taxis already out there."
Even though it predated what are called transportation network companies, Flywheel failed to find traction or funding in its first go-round.
Now, the company changed its name, lined up $22.8 million in venture backing (from Shasta Ventures, Rockport and Craton Equity Partners), overhauled the app, and launched a big push into three markets: San Francisco, Seattle and Los Angeles.
"A year ago Flywheel was in 400 cabs in San Francisco," Humphreys said. "Now we have 1,200."
Flywheel hopes to sign up cab companies to equip all their vehicles with the app. Luxor, the city's second-largest fleet with 252 cabs, was the most recent addition.
"Flywheel helps with good, quick, efficient services based on today's economy of real time," said Luxor President John Lazar. "People like to be able to push a button (on their phone) and have a car come to them."
San Francisco's biggest taxi company, Yellow Cab with 600 vehicles, isn't on board with Flywheel. General manager Jim Gillespie said Yellow is using a Flywheel rival called Taxi Magic (mainly used in Washington, D.C.) while it develops its own app.
"Some people accuse (the taxi industry) of being the horse and buggy and saying we have to catch up," he said. "This is the era of the app."
Other ways cab industry is battling for its territory
In addition to Flywheel, taxis are trying legislative and investigative tactics to combat the new companies' incursion on their turf.
Jim Gillespie, president of the Taxicab Paratransit Association of California, said it has lined up state lawmakers to introduce a bill this month requiring the transportation network company vehicles to carry more insurance, register cars as commercial vehicles, undergo car inspections and use public-agency background checks for drivers.
"We believe they should be regulated as taxis, with the same requirements taxis have," he said.
Other cabdrivers are adopting a more aggressive approach. Luxor Cab driver Trevor Johnson, a board member of the San Francisco Cab Drivers Association, has marshaled "an army" of 200 or 300 San Francisco cabdrivers to photograph license plates of cars that appear to be driving for UberX, Lyft or Sidecar.
"We've identified over 3,500 individual vehicles operating as (transportation network company) cars," he said. That's more than twice San Francisco's 1,800 cabs.
Johnson is assembling the plate numbers into a database that he shares with law enforcement, legislators, regulators and insurance companies.
"We give access to the data to any insurance investigators that request it," he said.
Personal car insurance policies don't cover accidents that occur during commercial use, according to the state Department of Insurance. Some insurers may cancel policies if they discover that policyholders are using their cars for hire.
The database has already had one effect.
"I don't use the pink mustache anymore," said a Lyft driver who asked not to be identified because he fears being dropped by his insurer. "On our Facebook group, the drivers were all saying to hide it so the cabdrivers can't spot us."