For Maria Eloisa Bantique, weaving through the beelines of smoke-belching cars in Manila to find a driver keen on buying car knick-knacks is a necessary means of making a living.

The mother of seven is one of many street vendors who plough through the Philippine capital's notoriously congested roads and highways every day, turning what is otherwise a drain on the country's economy into their main source of income.

"I am only a simple vendor but I am not ashamed of being a vendor," she said, while holding a collection of feather dusters and a Mickey Mouse-themed car window sunshade.

Metro Manila, a sprawl of 16 cities fused together by outdated infrastructure, is creaking under the weight of millions of vehicles, owing largely to economic growth of more than six percent a year since 2012. Urban rail coverage is limited, trains are prone to breakdowns and queues spill onto streets where exhaust fumes are intoxicating.

Street vendors are technically not allowed to be on the main highways, but traffic police tend to turn a blind eye. Some residents of the capital complain that the vendors contribute to the slow-moving traffic, but they themselves disagree.

"For us, we don't think we're obstructing anyone because when we know it's time to move, we all walk to the side. Why would we still be out there when it's time to move? We could die in the middle of traffic," said Bantique.

Street vendors, selling anything from car accessories to snacks, basketballs, and even bonsai trees, have become an integral part of the scene.

"Here, it is made so easy for us, and it at least allows us to help others who are trying to find a living out here on the road," said one driver, Edwin Manolo, after buying a cable to charge his mobile phone.

Bantique says street vendors in Manila earn an average of $10 a day, which is marginally above minimum wage, though getting that on any given day is never certain. The custom of haggling makes things extra difficult, particularly for those who opt to sell more unique items hoping for higher returns.

"It's important not to have a hot head. When you look at them and they don't seem to be interested, you go away and move on to someone else," said Jojo Tarog, who sells bonsai trees, adding; "Always smile. When the customer sees you smiling, they'll be smiling, too."