The emergency lane of the expressway is not the place to stop and check your route. The key word here is distraction. Kids get bored easily so plan your trip accordingly. Plan a stop every two hours. Drivers should break at this point anyway to avoid driver fatigue.
Seatbelts Make sure the kids are in proper seats and belted up.
Accidents on the freeway are much less frequent than normal roads but when they do happen they do so at much higher speeds. If you haven't trained your kids to accept the seatbelt yet you should start now. Singaporean authorities have been quite tolerant in the past but I am told this is about to change. Under no circumstances should a child ride on a parent's lap in the front. That is tantamount to using an infant as a living airbag.