?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.aulast=Tay&rft.aufirst=Richard&rft.au=Tay%2C+Richard&rft.issn=0022-5258&rft.title=Journal+of+Transport+Economics+and+Policy&rft.date=2003&rft.issue=3&rft.volume=37&rft.atitle=Marginal+Effects+of+Changing+the+Vehicle+Mix+on+Fatal+Crashes&rft.genre=article