Many 2000 vehicles have seen emission improvements by lowering tailpipe pollution.
(Many 2000 vehicles; have seen; emission improvements) Context(Many 2000 vehicles have seen,List([0, 28))):(Many 2000 vehicles; have seen emission improvements by lowering; tailpipe pollution)
Many 2000 vehicles have seen,List([0, 28))
Many 2000 vehicles Many 2000 vehicles
have seen have seen emission improvements by lowering
emission improvements
tailpipe pollution