How to reduce rush hour traffic into DC by as much as 50% (on certain routes)

Virginia HOV restrictions. Image from City of Alexandria website.

A couple months ago I met Patrick Hare, an ex-resident of Brookland, DC, and a planner, and the person who, while working for Montgomery County, came up with the idea for the Metropolitan Branch Trail. (See Geared to Everyone's Interests-A Brookland Bike Trail, Washington Post, Sep 24, 1989; b.08.)

He also told me about another idea he had, that just as Alexandria has instituted HOV-2 restrictions on certain roads during rush hour traffic periods, DC should do the same thing (HOV Lanes: Not Just for Highways, Washington Post; Jan 20, 1991; b.08).

I have been thinking about this quite a bit since. The other day, I pondered after paying attention to in-bound morning traffic on Rhode Island Avenue, Constitution Avenue, and Pennsylvania Avenue.

Since most of the cars have only one occupant, requiring that to use the roads during peak periods, two (or more) people would need to be in each car would likely cut traffic by almost half.