"I've never had a problem -- never, ever had a problem," Randy Frost told ABCNews.com.
At 500 pounds, Frost has used Fresno's Handy Ride bus for nearly three years to get groceries, go shopping and visit his doctors.
The procedure has always been the same -- he uses a cane to board the bus first, using the handicap-accessible ramp. Then the driver loads his motorized chair behind him.
But Frost said he's now being refused a renewal of his Handy Ride pass, told by the city that that his girth and the weight of his motorized chair combined exceed the 600-pound weight limit on the bus' handicap ramp.
Frost estimates the chair -- which he uses because of his severely arthritic hips, not his weight -- weighs about 200 pounds.
As what he sees an added insult, Frost said he was asked to come down to a city office and get weighed and measured by the Department of Transportation and told it was just like on a carnival ride where the operator has to check to make sure the rider fits. He refused.
"This is not a carnival ride," Frost said. "This is something I need to live."
Frost, who was once bedridden for three years before losing more than 200 pounds, said he was told he never should have been allowed on the bus in the first place.
And the 49-year-old former construction worker said he was surprised to hear Fresno Transportation Director Ken Hamm tell ABC's Fresno affiliate KFSN that the city was cracking down on who was allowed on the handicap bus to cut down on costs.
"It just supports my theory that they're grasping at straws to save a buck," he said. "It's humiliating."
Hamm could not immediately be reached for comment, but he told KFSN that the procedure Frost had been going through to board the bus was dangerous.
"It's really a safety factor for the customer and a safety factor for us," he told the station. "We are following the requirement of the Americans with Disabilities Act to the letter on this one."
Frost's not buying it. He said he was never asked to be weighed and measured when he first got the pass nearly three years ago. At the time he had left a nursing home after bringing his weight down from a high of 732 pounds.
Obesity and Transportation: Time for a Truce?
The plight of the obese on public transportation has made headlines this week after movie director and actor Kevin Smith tweeted that he was kicked off a Southwest Airlines flight because he was too big to fit into a seat.
His ensuing Twitter war with the airline thrust the increasingly public debate over weight into spotlight again, with no shortage of opinion on either side.
"The public transportation stuff has been coming up more and more frequently," Rebecca Puhl, director of research for the Rudd Center on Food Policy and Obesity at Yale University, told ABCNews.com. "People regardless of their body size have the right to be treated fairly, with dignity."
The high percentage of obese Americans -- 34 percent -- is a population that's not going to be changing anytime soon, Puhl said, recommending the transportation industry find ways to accommodate the one-third of their passengers they alienate when cases like Smith's or Frost's make news.
"If we were talking about a different type of physical disability ... we probably wouldn't be having this conversation," she said.
In Frost's case, she said, denying him a pass for a service he's been using for years seems unfair. And she called the request for him to be weighed and measured "appalling."
Frost, whose weight continues to drop through diet and walking as much as he can, said he'd consider a lawsuit just to be allowed back on the bus. He's been taking his motorized chair to the local markets and found a doctor that will come to him.
But he doesn't want to be confined to a mile radius around his apartment complex and said he already missed an appointment with the housing authority earlier this month because he was not allowed on the Handy Ride bus.
"I'm not out for monetary gain," he said. "But I need transportation."