In addition to the reason already given (kids get home before the evening traffic picks up), another reason is that generally driving conditions are worse in the morning than they are in the evening so if there isn't enough light for both the morning and evening drives to be in light it is safer to give the light to the morning drive.

> another reason is that generally driving conditions are worse in the morning than they are in the evening

Wait, why? Where? I've never heard this. Which driving conditions are you talking about? Rain? Snow?

> kids get home before the evening traffic picks up

When we change the general time, this applies to school days as well as office hours, so the kids go home to evening traffic relation will stay constant.