Complex sentence: Safety concerns have precipitated many construction projects on the bridge in the 1980s and 1990s due to the narrow width of the roadway and high traffic volume and the bridge deck is prone to severe icing conditions in winter, leading to motor vehicle accidents.
Split into simpler sentences: Safety concerns have precipitated many construction projects on the bridge in the 1980s and 1990s, due in part to the narrow width of the roadway and to high traffic volume. The bridge deck is prone to severe icing conditions in winter, leading to motor vehicle accidents.