when my Dh used to ride a lot with my sons he'd make a "Tom Sandwich"
older son in front, younger (Tom) in the middle and DH in the rear.
Of course that also switched when DH had to make a decision about a turn or a stop... but when things got tight every now and then in traffic; that's what they did. And younger son did a double century (Seattle to Portland) when he was 11 so all that riding paid off.