Commuting on the Long Island Expressway changed 20 years ago when the first high-occupancy vehicle lanes opened.

But two decades later, some drivers say the HOV lanes are a failure, in part because of the large number "clean-pass vehicles" that now use the lanes.

These vehicles are low-emission or low-polluting cars, like hybrids and electric cars. They have special stickers on their bumpers allowing them to use the HOV lanes, even with just one person behind the wheel.

But critics say the high volume of clean cars are slowing down the HOV lanes and discouraging people from carpooling.

According to the Department of Transportation, an average of 1,570 cars use the HOV lanes weekdays between 7 a.m. and 8 a.m. Nearly half of those cars are one-passenger, clean pass vehicles.

At the same time, fewer commuters are carpooling. Ride-sharing service 511NY Rideshare says it signed up 10,000 potential car poolers since 2010, but it reports that only 3,000 are still sharing rides.

Former Suffolk County Executive Steve Levy tried to limit the number of clean pass cars using HOV lanes. He believes the rules need to be changed.

Long Island's AAA believes clean-pass drivers should be able to use HOV lanes with or without passengers, because the mileage and pollution benefits that hybrids and high-mileage vehicles offer is considerable.