House Minority Leader Nancy Pelosi helped secure $3 million last year for a nonprofit transportation-research organization whose president gave money to her political action committee as the group was paying for a European trip for one of her policy advisers.

Transportation adviser Lara Levison's nine-day, $4,475 trip to Spain and Germany last April to learn about hydrogen-fuel cells for buses was primarily paid for by WestStart-CALSTART.

But just days before the trip, WestStart-CALSTART announced that Mrs. Pelosi had helped the nonprofit group secure $1 million from the Federal Transit Administration for a bus rapid-transit program. A month after the Levison trip, the group sent out a press release thanking her for a $2 million grant for a fuel-cell program...