Speed: 1-3
1 - 1d3
Speed: 4-6
1 - 1d4
Speed: 7-10
1 - 1d6
Speed: 11-13
1 - 1d8
Speed: 14-17
1 - 1d10
Speed: 18-20
1 - 1d12
Speed: 21+
1 - 2d8; + 1d3 every 2 additional speed