At present, there are thirty-four compressed natural gas (CNG) buses operating out of Brooklyn's depot, and 190 CNG buses are scheduled to join them later this year. 250 more are being ordered for delivery in 2001. On top of that, Harlem's 250-bus depot is supposed to be converted for CNG bus operation by 2003.

Based on the approximately 3,300 bus fleet that NYC Transit anticipated prior to the advent of MetroCard fare discounts, these CNG buses would have constituted over 20% of the entire fleet. But the discount-induced rider boom now has Transit talking about a fleet of 4,000, meaning that CNG buses will provide the margin for expansion, but will not displace today's diesels.

The need to expand the clean-fuel bus program is becoming more urgent as diesel impacts are further evaluated. California is now set to classify diesel particulate pollution as a carcinogen.

Although transit agencies around the country have shown that CNG buses work for city transit, the MTA remains intent on producing its diesel-electric hybrid bus. The hybrid is more efficient than today's old diesels but still would contribute to diesel pollution.

Some are concerned that the MTA will renege on its pledge to make Harlem's depot a garage for CNG buses, and instead station the first hybrid-electric buses there. But it's unclear whether the hybrids will be ready for regular service by the time the depot is supposed to become operational with clean fuel buses.