MEXICO CITY (AP) - So what if they rage through traffic, cause at least one accident a day and barely stop for passengers. Drivers of Mexico City's rickety old "pesero" buses say they deserve tips for their harrowing rides.

Since the city approved a fare hike only for newer buses, the union representing pesero drivers says passengers will be asked to pay tips of at least 50 Mexican cents ($0.05) on top of their normal fares to cover gasoline, maintenance and driver training.

The green and white peseros are 20 years old on average, causing major pollution and at least one accident a day, officials said.

But drivers say can't afford to replace them: "How can the government demand we give first-class service with third-rate bus fares?" union chief Jose Luis Tenorio said Wednesday.