“Car of the Future” (8 p.m., PBS): You couldn’t ask for better traveling

“Car of the Future” (8 p.m., PBS): You couldn’t ask for better traveling companions than “Car Talk” radio hosts Tom and Ray Magliozzi when PBS’ “NOVA” goes in search of the “Car of the Future.” The wisecracking, car-wise Magliozzi brothers visit engineers and designers with high-rev concepts for better, more fuel-efficient ways to drive. And they ask the question: Will we get where we need to be, before it’s too late? The brothers make the scene at the souped-up North American International Auto Show in Detroit, and at the AltWheels Festival in Boston, where they squeeze into a tiny three-wheeler that boasts 100 miles per gallon (but zero elbow room). They investigate hydrogen-powered cars and cars you plug into a wall socket every night. This is an entertaining, informative progress report and call to action for a gas-guzzling age.

“Reaper” (9 p.m., CW): Steve and Tony set up a trap for Satan himself, but they have a devil of a time doing it.

“Law & Order: SVU” (10 p.m., NBC): Don’t look now, but Benson has a boyfriend on “Law & Order: SVU.” He’s a newspaper editor played by Bill Pullman. Unfortunately, their jobs have a way of getting in the way of a budding romance.

“The Return of the Cuyahoga” (10 p.m., PBS): It was one of America’s most polluted rivers. It was tarred with an image as “the river that burned,” which it did as far back as 1883. Once marking the edge of a young nation’s frontier, the Cuyahoga River, which flows through Akron and Cleveland, became a modern symbol of nationwide environmental damage. The fire that erupted on June 22, 1969, helped spur widespread reforms, including the Clean Water Act, the Clean Air Act and, beginning in 1970, Earth Day (April 22). A new documentary, “The Return of the Cuyahoga,” tells the story of this river’s life, death and rebirth. It airs in conjunction with Earth Day 2008.

“ESPN Films: Hellfighters” (9 p.m., ESPN2): The network airs the first of four consecutive Tuesdays of sports documentaries with a profile of a high school football team in Harlem, N.Y.