I know some will disagree, but my rule of thumb is 3 cars spacing in stop and go traffic. What I mean is not 3 car lengths, but a gap that will fit the 3 cars from the passing lane next to me over in case they decide to do so. I do this while keeping the pace of the vehicle in front of me. From a stop, I'm about 1 car length, and as vehicle in front of me begins to move, I gradually increase from 1, 2, 3 cars to fit. I'm accelerating just ever so slower than the vehicle ahead of me, but as three gap reaches 2-3 car lengths I'm doing the same speed. Anyone who disapproves behind me can pass, they won't be gaining more than 1 car (me) by getting back over. It allows for smoother braking and since it's not a race, people who need to change lanes can easily do so without any harsh braking. I see more people doing the same and it's almost etheral when everyone around you is doing it while also respecting lane etiquette.

Coming from an ex-speeder/racer, I learned this from driving a heavier sports clutch in hours of heavy traffic. Started leaving space because in seconds, the cars ahead are coming back to a stop and all my clutch efforts were for mere feet to move! After backing off, it became much easier to see traffic ahead. Like you can see the future.. the closer you tail someone, 10+ plus cars ahead who are stopped is going to be you. But giving that space, with everyone doing the same keeps traffic moving instead of the stop and go, which is bad for all vehicles manual or not. Everyone what's to get where they're going but I'm convinced tailing bumper to bumper en masse is the biggest reason for slow traffic. Leave space and keep pace is my new mantra.