MANILA, Philippines (AP) — Philippine transport groups launched a nationwide strike Monday to protest a government program drivers fear would phase out traditional jeepneys, which have become a cultural icon, and other aging public transport vehicles.

Officials, however, braced with contingencies, including the deployment of government vehicles to take stranded passengers. Other groups refused to join the weeklong strike that could keep more than 40,000 passenger jeepneys and vans off the streets in the Manila metropolis alone.

Protesting drivers and supporters held a noisy rally in suburban Quezon city in the capital region, then proceeded in a convoy to a government transport regulatory office to press their protest.

“We're calling on the public to support the transport strike in any way possible,” said Renato Reyes of the left-wing political alliance Bayan, which was backing the strike. “The inconvenience of the transport stoppage is temporary, but the loss of livelihood of drivers and operators would be long-term.”

At almost noon, Transport Secretary Jaime Bautista said no major transport disruption had been monitored. Other officials said government vehicles were deployed to carry commuters in some areas but did not immediately provide more details.

Morning rush-hour traffic was heavy as usual in major roads in Manila and nearby cities.

Bautista warned that protesting drivers who would resort to violence and coercion to stop passenger vehicles not joining the strike would face criminal charges.

The government transport modernization program, first launched in 2017, aims to replace dilapidated and dangerous passenger jeepneys and vans with modern vehicles, which have safety features and conform with carbon emissions standards. Vehicle owners have to join transport cooperatives and corporations for better transport management.

Opponents say most poor drivers could not afford to purchase new passenger jeepneys even with promised government financial aid.

Others said the program would mean the demise of the gaudily decorated and brightly colored jeepneys, which have been regarded as Manila's “King of the Road” and a showcase of Philippine culture on wheels.

The diesel-powered jeepneys evolved from U.S. military jeeps that American forces left behind after World War II. The vehicles were modified and then reproduced, many with second-hand truck chassis, and for decades were the most popular form of land transport among the working class, even though they cough out dark fumes that have been blamed for Manila's notoriously polluted air.