11.   Greyhound screeches its bus fleet to a halt.

12.   Ricardo Yudice said the new measure would allow a gradual renovation of the bus fleets.

13.   The plan calls for the entire MTA bus fleet to be retrofitted within three years.

14.   The trial will be a major factor determining whether the devices are deployed in the rest of the bus fleet.

15.   Yet even the Moscow city government has so far failed to clean up the municipal bus fleet, which is also a major cause of the smoggy skies.