(S (S (BASENP (DT An) (NN investigation)) (VP (VBZ has) (VP (VBN begun) (S (VP (TO to) (VP (VB try) (S (VP (TO to) (VP (VB establish) (SBAR (IN whether) (S (BASENP (DT the) (ADJP (JJ icy) (CC and) (JJ snowy)) (NN weather) (NNS conditions)) (VP (VBD were) (NP (BASENP (DT a) (NN factor)) (PP (IN in) (BASENP (DT this) (NN collision)))))))))))))))) (PERIOD .))