Against the Time Change

By the time we get to the coldest months of the year, January and February, the days are beginning to lengthen, and the mornings are getting earlier. This means that the risk of early morning frost or ice on the roads is reduced, as it begins to thaw as the sun rises. The extra hour of daylight allows some time for ice to thaw and for fog to clear. This is especially important because there are often drops in temperature immediately before dawn which can create black ice. By the evening, even with early sunset, the road surface has had a day's heat, and the effects of cooling are not immediate.
 
If the hour is changed, we might not only suffer darker mornings, but also icy roads until around 9 o'clock, well past the time that most of the rush hour and school traffic has been out on the roads. Morning traffic is worse than that in the evening already (traffic is more concentrated over a shorter time), so it would be a recipe for disaster.
 
The argument that lighter evenings will mean less accidents is also a little spurious: the reason more people have accidents on dark evenings is precisely because they are dark. Make the morning rush hour dark, and more people will have accidents then.