Relative velocities between dust aggregates in a protoplanetary disc computed according to Weidenschilling (1977, panel a)), Andrews & Williams (2007, panel b)), and Desch (2007, panel c)); at 1 AU and a turbulence parameter of α = 10^-5. The velocity profiles are labelled in units of m s^-1. The sticking collisions observed are plotted as single points; circles indicate the M sample, diamonds indicate the CM sample, and triangles indicate the SP sample. The maximum speed at which sticking was observed (5.2 cm s^-1) is shown as a dashed line. In panel c), the dashed contour is outside of the depicted parameter field.