Vector velocity imaging can reveal both the magnitude and direction of the blood velocity. Several techniques have been suggested for estimating the velocity, and this paper compares the performance for directional beam-forming and transverse oscillation (TO) vector flow imaging (VFI). Data have been acquired using the SARUS experimental ultrasound scanner connected to a BK 8820e (BK Medical, Herlev, Denmark) convex array probe with 192 active elements. A duplex sequence with 129 B-mode emissions interleaved with 129 flow emissions has been made. The flow was generated in a recirculating flow rig with a stationary, laminar flow, and the volume flow was measured by a MAG 3000 (Danfos, Sønderbog, Denmark) magnetic flow meter for reference. Data were beamformed with an optimized transverse oscillation scheme for the TO VFI, and standard fourth-order estimators were employed for the velocity estimation. Directional RF lines were beamformed along the flow direction and cross-correlation employed to estimate the velocity magnitude. The velocities were determined for beam-to-flow angles of 60, 75 and 90 degrees. Using 32 emissions the standard deviation relative to the peak velocity for TO estimation was 7.0% at a beam-to-flow angle of 75° . This was 3.8% for directional beamforming and at 60° it was 2.2%. The general improvement, however, comes at an increase by a factor of roughly 11 in the number of calculations for the directional beamformation compared to the TO method.